Increase version number to 0.3.7

Signed-off-by: Antonio Niño Díaz <antonio_nd@outlook.com>

.checkpatch.conf

@@ -16,6 +16,9 @@
 # Show file line, not input line
 --showfile
 
+# Don't expect SPDX tag in the first line of a file
+--ignore SPDX_LICENSE_TAG
+
 # List of ignored rules
 # ---------------------
 
@@ -53,6 +56,9 @@
 # Prefer stdint.h types over kernel types
 --ignore PREFER_KERNEL_TYPES
 
+# Don't ask to replace sscanf by kstrto
+--ignore SSCANF_TO_KSTRTO
+
 # Parentheses can make the code clearer
 --ignore UNNECESSARY_PARENTHESES
 

.travis-checkpatch.sh

@@ -0,0 +1,48 @@
+#!/bin/bash
+
+echo "Checking code style..."
+
+# Return failure as soon as a command fails to execute
+
+set -e
+
+# Download checkpatch.pl and related files
+
+echo "Getting checkpatch.pl..."
+
+mkdir checkpatchdir
+
+wget https://raw.githubusercontent.com/torvalds/linux/master/scripts/checkpatch.pl
+mv checkpatch.pl checkpatchdir/checkpatch.pl
+chmod +x checkpatchdir/checkpatch.pl
+
+touch checkpatchdir/const_structs.checkpatch
+touch checkpatchdir/spelling.txt
+
+# Run checkpatch.pl on the new commits
+
+echo "Running checkpatch.pl..."
+
+fname=$(mktemp)
+rc=0
+
+git remote set-branches --add origin develop
+git fetch
+
+make CHECKPATCH=checkpatchdir/checkpatch.pl checkpatch > $fname
+
+cat $fname
+
+if grep "ERROR" $fname; then
+    # At least one error found
+    echo "Code style errors have been found!"
+    rc=1
+else
+    echo "No code style errors found, your patches are ready!"
+fi
+
+# Cleanup
+
+rm -rf checkpatchdir
+
+exit $rc

.travis.yml

@@ -10,5 +10,6 @@ compiler:
   - clang
   - gcc
 script:
+  - ./.travis-checkpatch.sh
   - cd test
   - ./run-tests.sh

CONTRIBUTING.rst

@@ -70,24 +70,29 @@ copyright and the reference to the MIT License.
 3. Create a new branch to work on. You could still work on ``develop``, but it's
    easier that way.
 
-4. Sign off your commits: ``git commit -s``
+4. Compile your changes with ``make develop`` instead of just ``make``. This
+   target checks for additional warnings. Your patches shouldn't introduce any
+   new warning (but it may be possible to remove some warning checks if it makes
+   the code much easier).
 
-5. Follow the Linux kernel coding style, which can be found in the file
+5. Sign off your commits: ``git commit -s``
+
+6. Follow the Linux kernel coding style, which can be found in the file
    ``Documentation/process/coding-style.rst`` in the Linux kernel repository.
    Note that the coding style isn't writen on stone, if there is a good reason
    to deviate from it, it should be fine.
 
-6. Download the files ``checkpatch.pl``, ``const_structs.checkpatch`` and
+7. Download the files ``checkpatch.pl``, ``const_structs.checkpatch`` and
    ``spelling.txt`` from the folder ``scripts`` in the Linux kernel repository.
 
-7. To use ``checkpatch.pl`` you can use ``make checkpatch``, which will check
+8. To use ``checkpatch.pl`` you can use ``make checkpatch``, which will check
    the coding style of all patches between the current one and the upstream
    code. By default, the Makefile expects the script (and associate files) to be
    located in ``../linux/scripts/``, but you can place them anywhere you like as
    long as you specify it when executing the command:
    ``CHECKPATCH=../path/to/folder make checkpatch``.
 
-8. Create a pull request against the branch ``develop``.
+9. Create a pull request against the branch ``develop``.
 
-9. Be prepared to get some comments about your code and to modify it. Tip: Use
+10. Be prepared to get some comments about your code and to modify it. Tip: Use
-   ``git rebase -i origin/develop`` to modify chains of commits.
+    ``git rebase -i origin/develop`` to modify chains of commits.

CONTRIBUTORS.rst

@@ -30,6 +30,8 @@ Other contributors
 
 - The Musl C library <http://www.musl-libc.org>
 
+- obskyr <powpowd@gmail.com>
+
 - The OpenBSD Project <http://www.openbsd.org>
 
 - Sanqui <gsanky@gmail.com>

Makefile

@@ -26,7 +26,7 @@ PNGLDLIBS	:= `${PKG_CONFIG} --static --libs-only-l libpng`
 
 VERSION_STRING	:= `git describe --tags --dirty --always 2>/dev/null`
 
-WARNFLAGS	:= -Wall -Werror
+WARNFLAGS	:= -Wall
 
 # Overridable CFLAGS
 CFLAGS		:= -g
@@ -160,6 +160,7 @@ install: all
 
 # Target used to check the coding style of the whole codebase. '.y' and '.l'
 # files aren't checked, unfortunately...
+
 checkcodebase:
 	$Qfor file in `git ls-files | grep -E '\.c|\.h' | grep -v '\.html'`; do	\
 		${CHECKPATCH} -f "$$file";					\
@@ -169,6 +170,7 @@ checkcodebase:
 # to the HEAD. Runs checkpatch once for each commit between the current HEAD and
 # the first common commit between the HEAD and origin/develop. '.y' and '.l'
 # files aren't checked, unfortunately...
+
 checkpatch:
 	$Qeval COMMON_COMMIT=$$(git merge-base HEAD origin/develop);	\
 	for commit in `git rev-list $$COMMON_COMMIT..HEAD`; do		\
@@ -180,7 +182,7 @@ checkpatch:
 # Target for the project maintainer to easily create web manuals.
 # It relies on mandoc: http://mdocml.bsd.lv
 
-MANDOC	:= -Thtml -Ios=General -Oman=%N.%S.html -Ostyle=manual.css
+MANDOC	:= -Thtml -Ios=General -Oman=%N.%S.html -Ostyle=mandoc.css
 
 wwwman:
 	$Qmandoc ${MANDOC} src/rgbds.7 > docs/rgbds.7.html
@@ -193,6 +195,25 @@ wwwman:
 	$Qmandoc ${MANDOC} src/link/rgblink.5 > docs/rgblink.5.html
 	$Qmandoc ${MANDOC} src/gfx/rgbgfx.1 > docs/rgbgfx.1.html
 
+# This target is used during development in order to prevent adding new issues
+# to the source code. All warnings are treated as errors in order to block the
+# compilation and make the continous integration infrastructure return failure.
+
+develop:
+	$Qenv make -j WARNFLAGS="-Werror -Wall -Wextra -Wpedantic \
+		-Wno-sign-compare -Wchkp -Wformat=2 -Wformat-overflow=2 \
+		-Wformat-truncation=1 -Wformat-y2k -Wswitch-enum -Wunused \
+		-Wuninitialized -Wunknown-pragmas -Wstrict-overflow=5 \
+		-Wstringop-overflow=4 -Walloc-zero -Wduplicated-cond \
+		-Wfloat-equal -Wshadow -Wcast-qual -Wcast-align -Wlogical-op \
+		-Wnested-externs -Wno-aggressive-loop-optimizations -Winline \
+		-Wundef -Wstrict-prototypes -Wold-style-definition \
+		-fsanitize=shift -fsanitize=integer-divide-by-zero \
+		-fsanitize=unreachable -fsanitize=vla-bound \
+		-fsanitize=signed-integer-overflow -fsanitize=bounds \
+		-fsanitize=object-size -fsanitize=bool -fsanitize=enum \
+		-fsanitize=alignment -fsanitize=null"
+
 # Targets for the project maintainer to easily create Windows exes.
 # This is not for Windows users!
 # If you're building on Windows with Cygwin or Mingw, just follow the Unix
@@ -200,7 +221,7 @@ wwwman:
 
 mingw32:
 	$Qenv PKG_CONFIG_PATH=/usr/i686-w64-mingw32/sys-root/mingw/lib/pkgconfig/ \
-		make CC=i686-w64-mingw32-gcc YACC=bison WARNFLAGS= -j
+		make CC=i686-w64-mingw32-gcc YACC=bison -j
 	$Qmv rgbasm rgbasm.exe
 	$Qmv rgblink rgblink.exe
 	$Qmv rgbfix rgbfix.exe
@@ -208,7 +229,7 @@ mingw32:
 
 mingw64:
 	$Qenv PKG_CONFIG_PATH=/usr/x86_64-w64-mingw32/sys-root/mingw/lib/pkgconfig/ \
-		make CC=x86_64-w64-mingw32-gcc YACC=bison WARNFLAGS= -j
+		make CC=x86_64-w64-mingw32-gcc YACC=bison -j
 	$Qmv rgbasm rgbasm.exe
 	$Qmv rgblink rgblink.exe
 	$Qmv rgbfix rgbfix.exe

docs/gbz80.7.html

@@ -8,7 +8,7 @@
     td.head-vol { text-align: center; }
     div.Pp { margin: 1ex 0ex; }
   </style>
-  <link rel="stylesheet" href="manual.css" type="text/css" media="all"/>
+  <link rel="stylesheet" href="mandoc.css" type="text/css" media="all"/>
   <title>GBZ80(7)</title>
 </head>
 <body>
@@ -34,8 +34,12 @@ Note: All arithmetic/logic operations that use register
   is assumed it's register <b class="Sy" title="Sy">A</b>. The following two
   lines have the same effect:
 <div class="Pp"></div>
-<div class="D1"><code class="Li">OR A,B</code></div>
+<div class="Bd" style="margin-left: 5.00ex;">
-<div class="D1"><code class="Li">OR B</code></div>
+<pre class="Li">
+OR A,B 
+OR B
+</pre>
+</div>
 <h1 class="Sh" title="Sh" id="LEGEND"><a class="selflink" href="#LEGEND">LEGEND</a></h1>
 List of abbreviations used in this document.
 <dl class="Bl-tag">
@@ -1689,7 +1693,7 @@ Flags: See <a class="Sx" title="Sx" href="#XOR_A,r8">XOR A,r8</a>
   <a class="Lk" title="Lk" href="https://github.com/rednex/rgbds">https://github.com/rednex/rgbds</a>.</div>
 <table class="foot">
   <tr>
-    <td class="foot-date">January 26, 2018</td>
+    <td class="foot-date">February 23, 2018</td>
     <td class="foot-os">RGBDS Manual</td>
   </tr>
 </table>

docs/index.html

@@ -1,32 +1,36 @@
-<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
+<!DOCTYPE html>
 <html>
 <head>
-	<meta http-equiv="Content-Type" content="text/html;charset=UTF-8">
+  <meta charset="utf-8"/>
-	<title>General Information</title>
+  <meta http-equiv="Content-Type" content="text/html;charset=UTF-8">
-	<link rel="stylesheet" type="text/css" href="./style.css">
+  <title>General Information</title>
+  <link rel="stylesheet" type="text/css" href="mandoc.css">
 </head>
 <body>
 <h1>RGBDS — Rednex Game Boy Development System</h1>
 <h2>Table of Contents</h2>
+<ol>
+  <li>General information
+    <ul>
+      <li><a href="rgbds.7.html">RGBDS general information</a></li>
+      <li><a href="rgbds.5.html">RGBDS object file format</a></li>
+    </ul>
+  <li>Language description
+    <ul>
+      <li><a href="rgbasm.5.html">RGBASM language description</a></li>
+      <li><a href="rgblink.5.html">RGBLINK linkerscript language description</a></li>
+      <li><a href="gbz80.7.html">GBZ80 CPU instruction set description</a></li>
+    </ul>
+  <li>Command line usage
+    <ul>
+      <li><a href="rgbasm.1.html">RGBASM command-line usage</a></li>
+      <li><a href="rgblink.1.html">RGBLINK command-line usage</a></li>
+      <li><a href="rgbfix.1.html">RGBFIX command-line usage</a></li>
+      <li><a href="rgbgfx.1.html">RGBGFX command-line usage</a></li>
+    </ul>
+</ol>
+<h2 id="GitHub Repository">GitHub Repository:</h2>
 <ul>
-	<li><a href="rgbds.7.html">RGBDS general information</a>
+  <li><a href="https://github.com/rednex/rgbds">https://github.com/rednex/rgbds</a></li>
-</ul>
-<ul>
-	<li><a href="rgbasm.5.html">RGBASM language description</a>
-	<li><a href="rgblink.5.html">RGBLINK linkerscript language description</a>
-	<li><a href="gbz80.7.html">GBZ80 CPU instruction set description</a>
-</ul>
-<ul>
-	<li><a href="rgbasm.1.html">RGBASM command-line usage</a>
-	<li><a href="rgblink.1.html">RGBLINK command-line usage</a>
-	<li><a href="rgbfix.1.html">RGBFIX command-line usage</a>
-	<li><a href="rgbgfx.1.html">RGBGFX command-line usage</a>
-</ul>
-<ul>
-	<li><a href="rgbds.5.html">RGBDS object file format</a>
-</ul>
-<h3 id="GitHub Repository">GitHub Repository:</h3>
-<ul>
-	<li><a href="https://github.com/rednex/rgbds">https://github.com/rednex/rgbds</a>
 </ul>
 </body>

docs/mandoc.css

@@ -0,0 +1,203 @@
+/* $Id: mandoc.css,v 1.22 2017/07/16 18:45:00 schwarze Exp $ */
+/*
+ * Standard style sheet for mandoc(1) -Thtml and man.cgi(8).
+ */
+
+/* Global defaults. */
+
+html {		max-width: 100ex; }
+body {		font-family: Helvetica,Arial,sans-serif; }
+table {		margin-top: 0em;
+		margin-bottom: 0em; }
+td {		vertical-align: top; }
+ul, ol, dl {	margin-top: 0em;
+		margin-bottom: 0em; }
+li, dt {	margin-top: 1em; }
+
+a.selflink {	border-bottom: thin dotted;
+		color: inherit;
+		font: inherit;
+		text-decoration: inherit; }
+* {		clear: both }
+
+/* Search form and search results. */
+
+fieldset {	border: thin solid silver;
+		border-radius: 1em;
+		text-align: center; }
+input[name=expr] {
+		width: 25%; }
+
+table.results {	margin-top: 1em;
+		margin-left: 2em;
+		font-size: smaller; }
+
+/* Header and footer lines. */
+
+table.head {	width: 100%;
+		border-bottom: 1px dotted #808080;
+		margin-bottom: 1em;
+		font-size: smaller; }
+td.head-vol {	text-align: center; }
+td.head-rtitle {
+		text-align: right; }
+span.Nd { }
+
+table.foot {	width: 100%;
+		border-top: 1px dotted #808080;
+		margin-top: 1em;
+		font-size: smaller; }
+td.foot-os {	text-align: right; }
+
+/* Sections and paragraphs. */
+
+div.manual-text {
+		margin-left: 5ex; }
+h1.Sh {		margin-top: 2ex;
+		margin-bottom: 1ex;
+		margin-left: -4ex;
+		font-size: 110%; }
+h2.Ss {		margin-top: 2ex;
+		margin-bottom: 1ex;
+		margin-left: -2ex;
+		font-size: 105%; }
+div.Pp {	margin: 1ex 0ex; }
+a.Sx { }
+a.Xr { }
+
+/* Displays and lists. */
+
+div.Bd { }
+div.D1 {	margin-left: 5ex; }
+
+ul.Bl-bullet {	list-style-type: disc;
+		padding-left: 1em; }
+li.It-bullet { }
+ul.Bl-dash {	list-style-type: none;
+		padding-left: 0em; }
+li.It-dash:before {
+		content: "\2014  "; }
+ul.Bl-item {	list-style-type: none;
+		padding-left: 0em; }
+li.It-item { }
+ul.Bl-compact > li {
+		margin-top: 0ex; }
+
+ol.Bl-enum {	padding-left: 2em; }
+li.It-enum { }
+ol.Bl-compact > li {
+		margin-top: 0ex; }
+
+dl.Bl-diag { }
+dt.It-diag { }
+dd.It-diag {	margin-left: 0ex; }
+b.It-diag {	font-style: normal; }
+dl.Bl-hang { }
+dt.It-hang { }
+dd.It-hang {	margin-left: 10.2ex; }
+dl.Bl-inset { }
+dt.It-inset { }
+dd.It-inset {	margin-left: 0ex; }
+dl.Bl-ohang { }
+dt.It-ohang { }
+dd.It-ohang {	margin-left: 0ex; }
+dl.Bl-tag {	margin-left: 10.2ex; }
+dt.It-tag {	float: left;
+		margin-top: 0ex;
+		margin-left: -10.2ex;
+		padding-right: 2ex;
+		vertical-align: top; }
+dd.It-tag {	clear: right;
+		width: 100%;
+		margin-top: 0ex;
+		margin-left: 0ex;
+		vertical-align: top;
+		overflow: auto; }
+dl.Bl-compact > dt {
+		margin-top: 0ex; }
+
+table.Bl-column { }
+tr.It-column { }
+td.It-column {	margin-top: 1em; }
+table.Bl-compact > tbody > tr > td {
+		margin-top: 0ex; }
+
+cite.Rs {	font-style: normal;
+		font-weight: normal; }
+span.RsA { }
+i.RsB {		font-weight: normal; }
+span.RsC { }
+span.RsD { }
+i.RsI {		font-weight: normal; }
+i.RsJ {		font-weight: normal; }
+span.RsN { }
+span.RsO { }
+span.RsP { }
+span.RsQ { }
+span.RsR { }
+span.RsT {	text-decoration: underline; }
+a.RsU { }
+span.RsV { }
+
+span.eqn { }
+table.tbl { }
+
+/* Semantic markup for command line utilities. */
+
+table.Nm { }
+b.Nm {		font-style: normal; }
+b.Fl {		font-style: normal; }
+b.Cm {		font-style: normal; }
+var.Ar {	font-style: italic;
+		font-weight: normal; }
+span.Op { }
+b.Ic {		font-style: normal; }
+code.Ev {	font-style: normal;
+		font-weight: normal;
+		font-family: monospace; }
+i.Pa {		font-weight: normal; }
+
+/* Semantic markup for function libraries. */
+
+span.Lb { }
+b.In {		font-style: normal; }
+a.In { }
+b.Fd {		font-style: normal; }
+var.Ft {	font-style: italic;
+		font-weight: normal; }
+b.Fn {		font-style: normal; }
+var.Fa {	font-style: italic;
+		font-weight: normal; }
+var.Vt {	font-style: italic;
+		font-weight: normal; }
+var.Va {	font-style: italic;
+		font-weight: normal; }
+code.Dv {	font-style: normal;
+		font-weight: normal;
+		font-family: monospace; }
+code.Er {	font-style: normal;
+		font-weight: normal;
+		font-family: monospace; }
+
+/* Various semantic markup. */
+
+span.An { }
+a.Lk { }
+a.Mt { }
+b.Cd {		font-style: normal; }
+i.Ad {		font-weight: normal; }
+b.Ms {		font-style: normal; }
+span.St { }
+a.Ux { }
+
+/* Physical markup. */
+
+.No {		font-style: normal;
+		font-weight: normal; }
+.Em {		font-style: italic;
+		font-weight: normal; }
+.Sy {		font-style: normal;
+		font-weight: bold; }
+.Li {		font-style: normal;
+		font-weight: normal;
+		font-family: monospace; }

docs/rgbasm.1.html

@@ -8,7 +8,7 @@
     td.head-vol { text-align: center; }
     div.Pp { margin: 1ex 0ex; }
   </style>
-  <link rel="stylesheet" href="manual.css" type="text/css" media="all"/>
+  <link rel="stylesheet" href="mandoc.css" type="text/css" media="all"/>
   <title>RGBASM(1)</title>
 </head>
 <body>
@@ -27,7 +27,7 @@
 <table class="Nm">
   <tr>
     <td><b class="Nm" title="Nm">rgbasm</b></td>
-    <td>[<span class="Op"><b class="Fl" title="Fl">-EhVvw</b></span>]
+    <td>[<span class="Op"><b class="Fl" title="Fl">-EhLVvw</b></span>]
       [<span class="Op"><b class="Fl" title="Fl">-b</b>
       <var class="Ar" title="Ar">chars</var></span>]
       [<span class="Op"><b class="Fl" title="Fl">-D</b>
@@ -89,6 +89,13 @@ The <b class="Nm" title="Nm">rgbasm</b> program creates an object file from an
   <dd class="It-tag">Add an include path.</dd>
   <dt class="It-tag">&#x00A0;</dt>
   <dd class="It-tag">&#x00A0;</dd>
+  <dt class="It-tag"><a class="selflink" href="#L"><b class="Fl" title="Fl" id="L">-L</b></a></dt>
+  <dd class="It-tag">Disable the optimization that turns loads of the form
+      <b class="Sy" title="Sy">LD [$FF00+n8],A</b> into the opcode
+      <b class="Sy" title="Sy">LDH [$FF00+n8],A</b> in order to have full
+      control of the result in the final ROM.</dd>
+  <dt class="It-tag">&#x00A0;</dt>
+  <dd class="It-tag">&#x00A0;</dd>
   <dt class="It-tag"><a class="selflink" href="#M"><b class="Fl" title="Fl" id="M">-M</b></a>
     <var class="Ar" title="Ar">dependfile</var></dt>
   <dd class="It-tag">Print <a class="Xr" title="Xr">make(1)</a> dependencies to
@@ -120,7 +127,11 @@ The <b class="Nm" title="Nm">rgbasm</b> program creates an object file from an
 <h1 class="Sh" title="Sh" id="EXAMPLES"><a class="selflink" href="#EXAMPLES">EXAMPLES</a></h1>
 Assembling a basic source file is simple:
 <div class="Pp"></div>
-<div class="D1">$ rgbasm -o bar.o foo.asm</div>
+<div class="Bd" style="margin-left: 5.00ex;">
+<pre class="Li">
+$ rgbasm -o bar.o foo.asm
+</pre>
+</div>
 <div class="Pp"></div>
 The resulting object file is not yet a usable ROM image &#x2014; it must first
   be run through <a class="Xr" title="Xr">rgblink(1)</a> and
@@ -138,7 +149,7 @@ The resulting object file is not yet a usable ROM image &#x2014; it must first
   <a class="Lk" title="Lk" href="https://github.com/rednex/rgbds">https://github.com/rednex/rgbds</a>.</div>
 <table class="foot">
   <tr>
-    <td class="foot-date">January 26, 2018</td>
+    <td class="foot-date">February 24, 2018</td>
     <td class="foot-os">RGBDS Manual</td>
   </tr>
 </table>

docs/rgbasm.5.html

@@ -8,7 +8,7 @@
     td.head-vol { text-align: center; }
     div.Pp { margin: 1ex 0ex; }
   </style>
-  <link rel="stylesheet" href="manual.css" type="text/css" media="all"/>
+  <link rel="stylesheet" href="mandoc.css" type="text/css" media="all"/>
   <title>RGBASM(5)</title>
 </head>
 <body>
@@ -38,16 +38,51 @@ The syntax is line&#x2010;based, just as in any other assembler, meaning that
 <div class="Pp"></div>
 Example:
 <div class="Pp"></div>
-<div class="D1"><code class="Li">John: ld a,87 ;Weee</code></div>
+<div class="Bd" style="margin-left: 5.00ex;">
+<pre class="Li">
+John: ld a,87 ;Weee
+</pre>
+</div>
 <div class="Pp"></div>
 All pseudo&#x2010;ops, mnemonics and registers (reserved keywords) are
   case&#x2010;insensitive and all labels are case&#x2010;sensitive.
+<div class="Pp"></div>
+There are two syntaxes for comments. In both cases, a comment ends at the end of
+  the line. The most common one is: anything that follows a semicolon
+  &quot;;&quot; (that isn't inside a string) is a comment. There is another
+  format: anything that follows a &quot;*&quot; that is placed right at the
+  start of a line is a comment. The assembler removes all comments from the code
+  before doing anything else.
+<div class="Pp"></div>
+Sometimes lines can be too long and it may be necessary to split them. The
+  syntax to do so is the following one:
+<div class="Pp"></div>
+<div class="Bd" style="margin-left: 5.00ex;">
+<pre class="Li">
+    DB 1, 2, 3, 4 \ 
+       5, 6, 7, 8
+</pre>
+</div>
+<div class="Pp"></div>
+This works anywhere in the code except inside of strings. To split strings it is
+  needed to use <b class="Sy" title="Sy">STRCAT</b> like this:
+<div class="Pp"></div>
+<div class="Bd" style="margin-left: 5.00ex;">
+<pre class="Li">
+    DB STRCAT(&quot;Hello &quot;, \ 
+              &quot;world!&quot;)
+</pre>
+</div>
 <h2 class="Ss" title="Ss" id="Sections"><a class="selflink" href="#Sections">Sections</a></h2>
 Before you can start writing code, you must define a section. This tells the
   assembler what kind of information follows and, if it is code, where to put
   it.
 <div class="Pp"></div>
-<div class="D1"><code class="Li">SECTION &quot;CoolStuff&quot;,ROMX</code></div>
+<div class="Bd" style="margin-left: 5.00ex;">
+<pre class="Li">
+    SECTION &quot;CoolStuff&quot;,ROMX
+</pre>
+</div>
 <div class="Pp"></div>
 This switches to the section called &quot;CoolStuff&quot; (or creates it if it
   doesn't already exist) and it defines it as a code section. All sections
@@ -119,7 +154,10 @@ Possible section types are as follows:
       <b class="Sy" title="Sy">LDH [$FF00+n8],A</b> and
       <b class="Sy" title="Sy">LDH A,[$FF00+n8]</b> syntax instead. This forces
       the assembler to emit the correct instruction and the linker to check if
-      the value is in the correct range.</dd>
+      the value is in the correct range. This optimization can be disabled by
+      passing the <b class="Fl" title="Fl">-L</b> flag to
+      <b class="Sy" title="Sy">rgbasm</b> as explained in
+      <a class="Xr" title="Xr">rgbasm(1)</a>.</dd>
 </dl>
 <div class="Pp"></div>
 A section is usually defined as a floating one, but the code can restrict where
@@ -130,25 +168,38 @@ If a section is defined with no indications, it is a floating section. The
   obligation to follow any specific rules. The following example defines a
   section that can be placed anywhere in any ROMX bank:
 <div class="Pp"></div>
-<div class="D1"><code class="Li">SECTION &quot;CoolStuff&quot;,ROMX</code></div>
+<div class="Bd" style="margin-left: 5.00ex;">
+<pre class="Li">
+    SECTION &quot;CoolStuff&quot;,ROMX
+</pre>
+</div>
 <div class="Pp"></div>
 If it is needed, the following syntax can be used to fix the base address of the
   section:
 <div class="Pp"></div>
-<div class="D1"><code class="Li">SECTION
+<div class="Bd" style="margin-left: 5.00ex;">
-  &quot;CoolStuff&quot;,ROMX[$4567]</code></div>
+<pre class="Li">
+    SECTION &quot;CoolStuff&quot;,ROMX[$4567]
+</pre>
+</div>
 <div class="Pp"></div>
 It won't, however, fix the bank number, which is left to the linker. If you also
   want to specify the bank you can do:
 <div class="Pp"></div>
-<div class="D1"><code class="Li">SECTION
+<div class="Bd" style="margin-left: 5.00ex;">
-  &quot;CoolStuff&quot;,ROMX[$4567],BANK[3]</code></div>
+<pre class="Li">
+    SECTION &quot;CoolStuff&quot;,ROMX[$4567],BANK[3]
+</pre>
+</div>
 <div class="Pp"></div>
 And if you only want to force the section into a certain bank, and not it's
   position within the bank, that's also possible:
 <div class="Pp"></div>
-<div class="D1"><code class="Li">SECTION
+<div class="Bd" style="margin-left: 5.00ex;">
-  &quot;CoolStuff&quot;,ROMX,BANK[7]</code></div>
+<pre class="Li">
+    SECTION &quot;CoolStuff&quot;,ROMX,BANK[7]
+</pre>
+</div>
 <div class="Pp"></div>
 In addition, you can specify byte alignment for a section. This ensures that the
   section starts at a memory address where the given number of least-significant
@@ -158,11 +209,13 @@ In addition, you can specify byte alignment for a section. This ensures that the
   needed to align the start of an array to 256 bytes to optimize the code that
   accesses it.
 <div class="Pp"></div>
-<div class="D1"><code class="Li">SECTION &quot;OAM Data&quot;,WRAM0,ALIGN[8];
+<div class="Bd" style="margin-left: 5.00ex;">
-  align to 256 bytes</code></div>
+<pre class="Li">
-<div class="Pp"></div>
+    SECTION &quot;OAM Data&quot;,WRAM0,ALIGN[8] ; align to 256 bytes 
-<div class="D1"><code class="Li">SECTION &quot;VRAM
+ 
-  Data&quot;,ROMX,BANK[2],ALIGN[4]; align to 16 bytes</code></div>
+    SECTION &quot;VRAM Data&quot;,ROMX,BANK[2],ALIGN[4] ; align to 16 bytes
+</pre>
+</div>
 <div class="Pp"></div>
 HINT: If you think this is a lot of typing for doing a simple
   <b class="Ic" title="Ic">ORG</b> type thing you can quite easily write an
@@ -251,8 +304,12 @@ ThisWillBeExported.too::
     EQUates are constant symbols. They can, for example, be used for things such
       as bit-definitions of hardware registers.
     <div class="Pp"></div>
-    <div class="D1"><code class="Li">EXIT_OK EQU $00</code></div>
+    <div class="Bd" style="margin-left: 5.00ex;">
-    <div class="D1"><code class="Li">EXIT_FAILURE EQU $01</code></div>
+    <pre class="Li">
+EXIT_OK      EQU $00 
+EXIT_FAILURE EQU $01
+    </pre>
+    </div>
     <div class="Pp"></div>
     Note that a colon (:) following the label-name is not allowed. EQUates
       cannot be exported and imported. They don't change their value during the
@@ -276,7 +333,11 @@ COUNT      SET ARRAY_SIZE+COUNT
       be exported and imported. Alternatively you can use = as a synonym for
       SET.
     <div class="Pp"></div>
-    <div class="D1"><code class="Li">COUNT = 2</code></div>
+    <div class="Bd" style="margin-left: 5.00ex;">
+    <pre class="Li">
+COUNT = 2
+    </pre>
+    </div>
   </dd>
   <dt class="It-hang"><b class="Sy" title="Sy">RSSET</b>,
     <b class="Sy" title="Sy">RSRESET</b>, <b class="Sy" title="Sy">RB</b>,
@@ -369,10 +430,10 @@ str_SIZEOF = 259
     <div class="Bd" style="margin-left: 5.00ex;">
     <pre class="Li">
 COUNTREG EQUS &quot;[hl+]&quot; 
-ld a,COUNTREG 
+    ld a,COUNTREG 
  
 PLAYER_NAME EQUS &quot;\&quot;John\&quot;&quot; 
-db PLAYER_NAME
+    db PLAYER_NAME
     </pre>
     </div>
     <div class="Pp"></div>
@@ -381,13 +442,20 @@ db PLAYER_NAME
     <div class="Pp"></div>
     This will be interpreted as:
     <div class="Pp"></div>
-    <div class="D1"><code class="Li">ld a,[hl+]</code></div>
+    <div class="Bd" style="margin-left: 5.00ex;">
-    <div class="D1"><code class="Li">db &quot;John&quot;</code></div>
+    <pre class="Li">
+    ld a,[hl+] 
+    db &quot;John&quot;
+    </pre>
+    </div>
     <div class="Pp"></div>
     String-symbols can also be used to define small one-line macros:
     <div class="Pp"></div>
-    <div class="D1"><code class="Li">PUSHA EQUS &quot;push af\npush bc\npush
+    <div class="Bd" style="margin-left: 5.00ex;">
-      de\npush hl\n&quot;</code></div>
+    <pre class="Li">
+PUSHA EQUS &quot;push af\npush bc\npush de\npush hl\n&quot;
+    </pre>
+    </div>
     <div class="Pp"></div>
     Note that a colon (:) following the label-name is not allowed. String
       equates can't be exported or imported.
@@ -501,7 +569,11 @@ LoopyMacro: MACRO
       address and the second being a bytecount. The macro will then reset all
       bytes in this range.
     <div class="Pp"></div>
-    <div class="D1"><code class="Li">LoopyMacro MyVars,54</code></div>
+    <div class="Bd" style="margin-left: 5.00ex;">
+    <pre class="Li">
+LoopyMacro MyVars,54
+    </pre>
+    </div>
     <div class="Pp"></div>
     Arguments are passed as string equates. There's no need to enclose them in
       quotes. An expression will not be evaluated first but passed directly.
@@ -516,6 +588,21 @@ LoopyMacro: MACRO
       use the first 9 like this. If you want to use the rest, you need to use
       the keyword <b class="Ic" title="Ic">SHIFT</b>.
     <div class="Pp"></div>
+    Line continuations work as usual inside macros or lists of arguments of
+      macros. Strings, however, are a bit trickier. The following example shows
+      how to use strings as arguments for a macro:
+    <div class="Pp"></div>
+    <div class="Bd" style="margin-left: 5.00ex;">
+    <pre class="Li">
+PrintMacro : MACRO 
+    PRINTT \1 
+ENDM 
+ 
+    PrintMacro STRCAT(\&quot;Hello\&quot;\,  \ 
+                      \&quot; world\\n\&quot;)
+    </pre>
+    </div>
+    <div class="Pp"></div>
     <b class="Ic" title="Ic">SHIFT</b> is a special command only available in
       macros. Very useful in REPT-blocks. It will &quot;shift&quot; the
       arguments by one &quot;to the left&quot;. <b class="Ic" title="Ic">\1</b>
@@ -701,8 +788,11 @@ The following symbols are defined by the assembler:
 <b class="Ic" title="Ic">DB</b> defines a list of bytes that will be stored in
   the final image. Ideal for tables and text (which is not zero-terminated).
 <div class="Pp"></div>
-<div class="D1"><code class="Li">DB 1,2,3,4,&quot;This is a
+<div class="Bd" style="margin-left: 5.00ex;">
-  string&quot;</code></div>
+<pre class="Li">
+DB 1,2,3,4,&quot;This is a string&quot;
+</pre>
+</div>
 <div class="Pp"></div>
 Alternatively, you can use <b class="Ic" title="Ic">DW</b> to store a list of
   words (16-bits) or <b class="Ic" title="Ic">DL</b> to store a list of
@@ -729,8 +819,11 @@ You can also use <b class="Ic" title="Ic">DB</b>,
   <b class="Ic" title="Ic">DW</b> and <b class="Ic" title="Ic">DL</b> without
   any arguments instead.
 <div class="Pp"></div>
-<div class="D1"><code class="Li">DS str_SIZEOF ;allocate str_SIZEOF
+<div class="Bd" style="margin-left: 5.00ex;">
-  bytes</code></div>
+<pre class="Li">
+DS str_SIZEOF ;allocate str_SIZEOF bytes
+</pre>
+</div>
 <h2 class="Ss" title="Ss" id="Including_binary_files"><a class="selflink" href="#Including_binary_files">Including
   binary files</a></h2>
 You probably have some graphics you'd like to include. Use
@@ -738,17 +831,23 @@ You probably have some graphics you'd like to include. Use
   the file isn't found in the current directory, the include-path list passed to
   the linker on the command line will be searched.
 <div class="Pp"></div>
-<div class="D1"><code class="Li">INCBIN &quot;titlepic.bin&quot;</code></div>
+<div class="Bd" style="margin-left: 5.00ex;">
-<div class="D1"><code class="Li">INCBIN &quot;sprites/hero.bin&quot;&#x00A0;;
+<pre class="Li">
-  UNIX</code></div>
+INCBIN &quot;titlepic.bin&quot; 
-<div class="D1"><code class="Li">INCBIN &quot;sprites\\hero.bin&quot;&#x00A0;;
+INCBIN &quot;sprites/hero.bin&quot;&#x00A0;; UNIX 
-  Windows</code></div>
+INCBIN &quot;sprites\\hero.bin&quot;&#x00A0;; Windows
+</pre>
+</div>
 <div class="Pp"></div>
 You can also include only part of a file with
   <b class="Ic" title="Ic">INCBIN</b>. The example below includes 256 bytes from
   data.bin starting from byte 78.
 <div class="Pp"></div>
-<div class="D1"><code class="Li">INCBIN &quot;data.bin&quot;,78,256</code></div>
+<div class="Bd" style="margin-left: 5.00ex;">
+<pre class="Li">
+INCBIN &quot;data.bin&quot;,78,256
+</pre>
+</div>
 <h2 class="Ss" title="Ss" id="Unions"><a class="selflink" href="#Unions">Unions</a></h2>
 Unions allow multiple memory allocations to share the same space in memory, like
   unions in C. This allows you to easily reuse memory for different purposes,
@@ -791,17 +890,20 @@ These three instructions type text and values to stdout. Useful for debugging
 <div class="Bd" style="margin-left: 5.00ex;">
 <pre class="Li">
 PRINTT &quot;I'm the greatest programmer in the whole wide world\n&quot; 
-PRINTV (2+3)/5 
+PRINTI (2 + 3) / 5 
-PRINTF MUL(3.14,3987.0)
+PRINTV $FF00 + $F0 
+PRINTF MUL(3.14, 3987.0)
 </pre>
 </div>
 <dl class="Bl-inset">
   <dt class="It-inset"><a class="selflink" href="#PRINTT"><b class="Ic" title="Ic" id="PRINTT">PRINTT</b></a></dt>
   <dd class="It-inset">prints out a string.</dd>
   <dt class="It-inset"><a class="selflink" href="#PRINTV"><b class="Ic" title="Ic" id="PRINTV">PRINTV</b></a></dt>
-  <dd class="It-inset">prints out an integer value or, as in the example, the
+  <dd class="It-inset">prints out an integer value in hexadecimal or, as in the
-      result of a calculation. Unsurprisingly, you can also print out a constant
+      example, the result of a calculation. Unsurprisingly, you can also print
-      symbols value.</dd>
+      out a constant symbols value.</dd>
+  <dt class="It-inset"><a class="selflink" href="#PRINTI"><b class="Ic" title="Ic" id="PRINTI">PRINTI</b></a></dt>
+  <dd class="It-inset">prints out a signed integer value.</dd>
   <dt class="It-inset"><a class="selflink" href="#PRINTF"><b class="Ic" title="Ic" id="PRINTF">PRINTF</b></a></dt>
   <dd class="It-inset">prints out a fixed point value.</dd>
 </dl>
@@ -860,7 +962,11 @@ Use <b class="Ic" title="Ic">INCLUDE</b> to process another assembler-file and
   <b class="Ic" title="Ic">INCLUDE</b> calls infinitely (or until you run out of
   memory, whichever comes first).
 <div class="Pp"></div>
-<div class="D1"><code class="Li">INCLUDE &quot;irq.inc&quot;</code></div>
+<div class="Bd" style="margin-left: 5.00ex;">
+<pre class="Li">
+    INCLUDE &quot;irq.inc&quot;
+</pre>
+</div>
 <h2 class="Ss" title="Ss" id="Conditional_assembling"><a class="selflink" href="#Conditional_assembling">Conditional
   assembling</a></h2>
 The four commands <b class="Ic" title="Ic">IF</b>,
@@ -917,7 +1023,11 @@ The last one, Gameboy graphics, is quite interesting and useful. The values are
   actually pixel values and it converts the &#x201C;chunky&#x201D; data to
   &#x201C;planar&#x201D; data as used in the Gameboy.
 <div class="Pp"></div>
-<div class="D1"><code class="Li">DW `01012323</code></div>
+<div class="Bd" style="margin-left: 5.00ex;">
+<pre class="Li">
+    DW `01012323
+</pre>
+</div>
 <div class="Pp"></div>
 Admittedly, an expression with just a single number is quite boring. To spice
   things up a bit there are a few operators you can use to perform calculations
@@ -1199,6 +1309,32 @@ Whenever the macro-language expects a string you can actually use a string
       returns the new string.</td>
   </tr>
 </table>
+<h2 class="Ss" title="Ss" id="Character_maps"><a class="selflink" href="#Character_maps">Character
+  maps</a></h2>
+When writing text that is meant to be displayed in the Game Boy, the ASCII
+  characters used in the source code may not be the same ones used in the
+  tileset used in the ROM. For example, the tiles used for uppercase letters may
+  be placed starting at tile index 128, which makes it difficult to add text
+  strings to the ROM.
+<div class="Pp"></div>
+Character maps allow the code to map strings up to 16 characters long to an
+  abitrary 8-bit value:
+<div class="Pp"></div>
+<div class="Bd" style="margin-left: 5.00ex;">
+<pre class="Li">
+CHARMAP &quot;&lt;LF&gt;&quot;, 10 
+CHARMAP &quot;&amp;iacute&quot;, 20 
+CHARMAP &quot;A&quot;, 128
+</pre>
+</div>
+<div class="Pp"></div>
+<b class="Sy" title="Sy">Note:</b> Character maps affect all strings in the file
+  from the point in which they are defined. This means that any string that the
+  code may want to print as debug information will also be affected by it.
+<div class="Pp"></div>
+<b class="Sy" title="Sy">Note:</b> The output value of a mapping can be 0. If
+  this happens, the assembler will treat this as the end of the string and the
+  rest of it will be trimmed.
 <h2 class="Ss" title="Ss" id="Other_functions"><a class="selflink" href="#Other_functions">Other
   functions</a></h2>
 There are a few other functions that do various useful things:
@@ -1319,6 +1455,8 @@ The options that OPT can modify are currently: <b class="Sy" title="Sy">b</b>,
   <dd class="It-inset"></dd>
   <dt class="It-inset"><a class="Sx" title="Sx" href="#BANK">BANK</a></dt>
   <dd class="It-inset"></dd>
+  <dt class="It-inset"><a class="Sx" title="Sx" href="#CHARMAP">CHARMAP</a></dt>
+  <dd class="It-inset"></dd>
   <dt class="It-inset"><a class="Sx" title="Sx" href="#COS">COS</a></dt>
   <dd class="It-inset"></dd>
   <dt class="It-inset"><a class="Sx" title="Sx" href="#DB">DB</a></dt>
@@ -1377,6 +1515,8 @@ The options that OPT can modify are currently: <b class="Sy" title="Sy">b</b>,
   <dd class="It-inset"></dd>
   <dt class="It-inset"><a class="Sx" title="Sx" href="#PRINTF">PRINTF</a></dt>
   <dd class="It-inset"></dd>
+  <dt class="It-inset"><a class="Sx" title="Sx" href="#PRINTI">PRINTI</a></dt>
+  <dd class="It-inset"></dd>
   <dt class="It-inset"><a class="Sx" title="Sx" href="#PRINTT">PRINTT</a></dt>
   <dd class="It-inset"></dd>
   <dt class="It-inset"><a class="Sx" title="Sx" href="#PRINTV">PRINTV</a></dt>
@@ -1451,7 +1591,7 @@ The options that OPT can modify are currently: <b class="Sy" title="Sy">b</b>,
   <a class="Lk" title="Lk" href="https://github.com/rednex/rgbds">https://github.com/rednex/rgbds</a>.</div>
 <table class="foot">
   <tr>
-    <td class="foot-date">January 27, 2018</td>
+    <td class="foot-date">March 13, 2018</td>
     <td class="foot-os">RGBDS Manual</td>
   </tr>
 </table>

docs/rgbds.5.html

@@ -8,7 +8,7 @@
     td.head-vol { text-align: center; }
     div.Pp { margin: 1ex 0ex; }
   </style>
-  <link rel="stylesheet" href="manual.css" type="text/css" media="all"/>
+  <link rel="stylesheet" href="mandoc.css" type="text/css" media="all"/>
   <title>RGBDS(5)</title>
 </head>
 <body>
@@ -65,7 +65,9 @@ REPT    NumberOfSymbols   ; Number of symbols defined in this object file.
         LONG    LineNum   ; Line number in the file where the symbol is defined. 
  
         LONG    SectionID ; The section number (of this object file) in which 
-                          ; this symbol is defined. 
+                          ; this symbol is defined. If it doesn't belong to any 
+                          ; specific section (like a constant), this field has 
+                          ; the value -1. 
  
         LONG    Value     ; The symbols value. It's the offset into that 
                           ; symbol's section. 
@@ -121,6 +123,7 @@ REPT NumberOfSections
             BYTE    Type         ; 0 = BYTE patch. 
                                  ; 1 = little endian WORD patch. 
                                  ; 2 = little endian LONG patch. 
+                                 ; 3 = JR offset value BYTE patch. 
  
             LONG    RPNSize      ; Size of the buffer with the RPN. 
                                  ; expression. 

docs/rgbds.7.html

@@ -8,7 +8,7 @@
     td.head-vol { text-align: center; }
     div.Pp { margin: 1ex 0ex; }
   </style>
-  <link rel="stylesheet" href="manual.css" type="text/css" media="all"/>
+  <link rel="stylesheet" href="mandoc.css" type="text/css" media="all"/>
   <title>RGBDS(7)</title>
 </head>
 <body>
@@ -26,9 +26,13 @@
 <h1 class="Sh" title="Sh" id="EXAMPLES"><a class="selflink" href="#EXAMPLES">EXAMPLES</a></h1>
 To get a working ROM image from a single assembly source file:
 <div class="Pp"></div>
-<div class="D1">$ rgbasm -o bar.o foo.asm</div>
+<div class="Bd" style="margin-left: 5.00ex;">
-<div class="D1">$ rgblink -o baz.gb bar.o</div>
+<pre class="Li">
-<div class="D1">$ rgbfix -v -p 0 baz.gb</div>
+$ rgbasm -o bar.o foo.asm 
+$ rgblink -o baz.gb bar.o 
+$ rgbfix -v -p 0 baz.gb
+</pre>
+</div>
 <h1 class="Sh" title="Sh" id="SEE_ALSO"><a class="selflink" href="#SEE_ALSO">SEE
   ALSO</a></h1>
 <a class="Xr" title="Xr">rgbasm(1)</a>, <a class="Xr" title="Xr">rgbfix(1)</a>,
@@ -52,13 +56,14 @@ To get a working ROM image from a single assembly source file:
   <dt class="It-ohang"></dt>
   <dd class="It-ohang">2017, Bentley's repository is moved to a neutral name. It
       is now maintained by a number of contributors at
-      <a class="Lk" title="Lk" href="https://github.com/rednex/rgbds">https://github.com/rednex/rgbds</a>.
+      <a class="Lk" title="Lk" href="https://github.com/rednex/rgbds">https://github.com/rednex/rgbds</a>.</dd>
-      2018, codebase relicensed under the MIT license.</dd>
+  <dt class="It-ohang"></dt>
+  <dd class="It-ohang">2018, codebase relicensed under the MIT license.</dd>
 </dl>
 </div>
 <table class="foot">
   <tr>
-    <td class="foot-date">January 26, 2018</td>
+    <td class="foot-date">March 7, 2018</td>
     <td class="foot-os">RGBDS Manual</td>
   </tr>
 </table>

docs/rgbfix.1.html

@@ -8,7 +8,7 @@
     td.head-vol { text-align: center; }
     div.Pp { margin: 1ex 0ex; }
   </style>
-  <link rel="stylesheet" href="manual.css" type="text/css" media="all"/>
+  <link rel="stylesheet" href="mandoc.css" type="text/css" media="all"/>
   <title>RGBFIX(1)</title>
 </head>
 <body>
@@ -28,6 +28,8 @@
   <tr>
     <td><b class="Nm" title="Nm">rgbfix</b></td>
     <td>[<span class="Op"><b class="Fl" title="Fl">-CcjsVv</b></span>]
+      [<span class="Op"><b class="Fl" title="Fl">-f</b>
+      <var class="Ar" title="Ar">fix_spec</var></span>]
       [<span class="Op"><b class="Fl" title="Fl">-i</b>
       <var class="Ar" title="Ar">game_id</var></span>]
       [<span class="Op"><b class="Fl" title="Fl">-k</b>
@@ -67,6 +69,32 @@ The <b class="Nm" title="Nm">rgbfix</b> program changes headers of Game Boy ROM
       <b class="Fl" title="Fl">-C</b> takes precedence.</dd>
   <dt class="It-tag">&#x00A0;</dt>
   <dd class="It-tag">&#x00A0;</dd>
+  <dt class="It-tag"><a class="selflink" href="#f"><b class="Fl" title="Fl" id="f">-f</b></a>
+    <var class="Ar" title="Ar">fix_spec</var></dt>
+  <dd class="It-tag">Fix certain header values that the Game Boy checks for
+      correctness. Alternatively, intentionally trash these values by writing
+      their binary inverse instead. <var class="Ar" title="Ar">fix_spec</var> is
+      a string containing any combination of the following characters:
+    <div class="Pp"></div>
+    <dl class="Bl-tag Bl-compact" style="margin-left: 5.40ex;">
+      <dt class="It-tag" style="margin-left: -5.40ex;"><a class="selflink" href="#l"><b class="Cm" title="Cm" id="l">l</b></a></dt>
+      <dd class="It-tag">Fix the Nintendo logo
+          (<i class="Ad">0x104</i>&#x2013;<i class="Ad">0x133</i>).</dd>
+      <dt class="It-tag" style="margin-left: -5.40ex;"><a class="selflink" href="#L"><b class="Cm" title="Cm" id="L">L</b></a></dt>
+      <dd class="It-tag">Trash the Nintendo logo.</dd>
+      <dt class="It-tag" style="margin-left: -5.40ex;"><a class="selflink" href="#h"><b class="Cm" title="Cm" id="h">h</b></a></dt>
+      <dd class="It-tag">Fix the header checksum (<i class="Ad">0x14D</i>).</dd>
+      <dt class="It-tag" style="margin-left: -5.40ex;"><a class="selflink" href="#H"><b class="Cm" title="Cm" id="H">H</b></a></dt>
+      <dd class="It-tag">Trash the header checksum.</dd>
+      <dt class="It-tag" style="margin-left: -5.40ex;"><a class="selflink" href="#g"><b class="Cm" title="Cm" id="g">g</b></a></dt>
+      <dd class="It-tag">Fix the global checksum
+          (<i class="Ad">0x14E</i>&#x2013;<i class="Ad">0x14F</i>).</dd>
+      <dt class="It-tag" style="margin-left: -5.40ex;"><a class="selflink" href="#G"><b class="Cm" title="Cm" id="G">G</b></a></dt>
+      <dd class="It-tag">Trash the global checksum.</dd>
+    </dl>
+  </dd>
+  <dt class="It-tag">&#x00A0;</dt>
+  <dd class="It-tag">&#x00A0;</dd>
   <dt class="It-tag"><a class="selflink" href="#i"><b class="Fl" title="Fl" id="i">-i</b></a>
     <var class="Ar" title="Ar">game_id</var></dt>
   <dd class="It-tag">Set the game ID string
@@ -141,10 +169,8 @@ The <b class="Nm" title="Nm">rgbfix</b> program changes headers of Game Boy ROM
   <dt class="It-tag">&#x00A0;</dt>
   <dd class="It-tag">&#x00A0;</dd>
   <dt class="It-tag"><a class="selflink" href="#v"><b class="Fl" title="Fl" id="v">-v</b></a></dt>
-  <dd class="It-tag">Validate the header and fix checksums: the Nintendo
+  <dd class="It-tag">Equivalent to <b class="Fl" title="Fl">-f</b>
-      character area (<i class="Ad">0x104</i>&#x2013;<i class="Ad">0x133</i>),
+      <b class="Cm" title="Cm">lhg</b>.</dd>
-      the header checksum (<i class="Ad">0x14D</i>), and the global checksum
-      (<i class="Ad">0x14E</i>&#x2013;<i class="Ad">0x14F</i>).</dd>
 </dl>
 <h1 class="Sh" title="Sh" id="EXAMPLES"><a class="selflink" href="#EXAMPLES">EXAMPLES</a></h1>
 Most values in the ROM header are only cosmetic. The bare minimum requirements
@@ -179,7 +205,7 @@ The following will duplicate the header (sans global checksum) of the game
   <a class="Lk" title="Lk" href="https://github.com/rednex/rgbds">https://github.com/rednex/rgbds</a>.</div>
 <table class="foot">
   <tr>
-    <td class="foot-date">January 26, 2018</td>
+    <td class="foot-date">March 11, 2018</td>
     <td class="foot-os">RGBDS Manual</td>
   </tr>
 </table>

docs/rgbgfx.1.html

@@ -8,7 +8,7 @@
     td.head-vol { text-align: center; }
     div.Pp { margin: 1ex 0ex; }
   </style>
-  <link rel="stylesheet" href="manual.css" type="text/css" media="all"/>
+  <link rel="stylesheet" href="mandoc.css" type="text/css" media="all"/>
   <title>RGBGFX(1)</title>
 </head>
 <body>
@@ -43,7 +43,28 @@
 </table>
 <h1 class="Sh" title="Sh" id="DESCRIPTION"><a class="selflink" href="#DESCRIPTION">DESCRIPTION</a></h1>
 The <b class="Nm" title="Nm">rgbgfx</b> program converts PNG images into the
-  Nintendo Game Boy's planar tile format. The arguments are as follows:
+  Nintendo Game Boy's planar tile format.
+<div style="height: 1.00em;">&#x00A0;</div>
+The resulting colors and their palette indices are determined differently
+  depending on the input PNG file:
+<ul class="Bl-dash">
+  <li class="It-dash">If the file has an embedded palette, that palette's color
+      and order are used.</li>
+  <li class="It-dash">If not, and the image only contains shades of gray, rgbgfx
+      maps them to the indices appropriate for each shade. Any undetermined
+      indices are set to respective default shades of gray. For example: if the
+      bit depth is 2 and the image contains light gray and black, they become
+      the second and fourth colors - and the first and third colors get set to
+      default white and dark gray. If the image has multiple shades that map to
+      the same index, the palette is instead determined as if the image had
+      color.</li>
+  <li class="It-dash">If the image has color (or the grayscale method failed),
+      the colors are sorted from lightest to darkest.</li>
+</ul>
+<div style="height: 1.00em;">&#x00A0;</div>
+The input image may not contain more colors than the selected bit depth allows.
+  Transparent pixels are set to palette index 0.
+<h1 class="Sh" title="Sh" id="ARGUMENTS"><a class="selflink" href="#ARGUMENTS">ARGUMENTS</a></h1>
 <dl class="Bl-tag">
   <dt class="It-tag">&#x00A0;</dt>
   <dd class="It-tag">&#x00A0;</dd>
@@ -58,14 +79,14 @@ The <b class="Nm" title="Nm">rgbgfx</b> program converts PNG images into the
   <dd class="It-tag">&#x00A0;</dd>
   <dt class="It-tag"><a class="selflink" href="#F"><b class="Fl" title="Fl" id="F">-F</b></a></dt>
   <dd class="It-tag">Same as <b class="Fl" title="Fl">-f</b>, but additionally,
-      the input PNG file is fixed to have its parameters match the command
+      the supplied command line parameters are saved within the PNG and will be
-      line's parameters.</dd>
+      loaded and automatically used next time.</dd>
   <dt class="It-tag">&#x00A0;</dt>
   <dd class="It-tag">&#x00A0;</dd>
   <dt class="It-tag"><a class="selflink" href="#d"><b class="Fl" title="Fl" id="d">-d</b></a>
     <var class="Ar" title="Ar">depth</var></dt>
-  <dd class="It-tag">The bitdepth of the output image (either 1 or 2). By
+  <dd class="It-tag">The bit depth of the output image (either 1 or 2). By
-      default, the bitdepth is 2 (two bits per pixel).</dd>
+      default, the bit depth is 2 (two bits per pixel).</dd>
   <dt class="It-tag">&#x00A0;</dt>
   <dd class="It-tag">&#x00A0;</dd>
   <dt class="It-tag"><a class="selflink" href="#h"><b class="Fl" title="Fl" id="h">-h</b></a></dt>
@@ -79,15 +100,16 @@ The <b class="Nm" title="Nm">rgbgfx</b> program converts PNG images into the
   <dd class="It-tag">&#x00A0;</dd>
   <dt class="It-tag"><a class="selflink" href="#p"><b class="Fl" title="Fl" id="p">-p</b></a>
     <var class="Ar" title="Ar">palfile</var></dt>
-  <dd class="It-tag">Raw bytes (8 bytes for two bits per pixel, 4 bytes for one
+  <dd class="It-tag">Output the image's palette in standard GBC palette format -
-      bit per pixel) containing the RGB15 values in the little-endian byte order
+      bytes (8 bytes for two bits per pixel, 4 bytes for one bit per pixel)
-      and then ordered from lightest to darkest.</dd>
+      containing the RGB15 values in little-endian byte order. If the palette
+      contains too few colors, the remaining entries are set to black.</dd>
   <dt class="It-tag">&#x00A0;</dt>
   <dd class="It-tag">&#x00A0;</dd>
   <dt class="It-tag"><a class="selflink" href="#P"><b class="Fl" title="Fl" id="P">-P</b></a></dt>
-  <dd class="It-tag">Same as <b class="Fl" title="Fl">-p</b>, but the pallete
+  <dd class="It-tag">Same as <b class="Fl" title="Fl">-p</b>, but the palette
-      file output name is made by taking the input filename, removing the file
+      file output name is made by taking the input PNG file's filename, removing
-      extension, and appending <i class="Pa" title="Pa">.pal</i>.</dd>
+      the file extension, and appending <i class="Pa" title="Pa">.pal</i>.</dd>
   <dt class="It-tag">&#x00A0;</dt>
   <dd class="It-tag">&#x00A0;</dd>
   <dt class="It-tag"><a class="selflink" href="#t"><b class="Fl" title="Fl" id="t">-t</b></a>
@@ -120,7 +142,7 @@ The <b class="Nm" title="Nm">rgbgfx</b> program converts PNG images into the
   <dd class="It-tag">Trim the end of the output file by this many tiles.</dd>
 </dl>
 <h1 class="Sh" title="Sh" id="EXAMPLES"><a class="selflink" href="#EXAMPLES">EXAMPLES</a></h1>
-The following will take a PNG file with a bitdepth of 1, 2, or 8, and output
+The following will take a PNG file with a bit depth of 1, 2, or 8, and output
   planar 2bpp data:
 <div class="Pp"></div>
 <div class="D1">$ rgbgfx -o out.2bpp in.png</div>

docs/rgblink.1.html

@@ -8,7 +8,7 @@
     td.head-vol { text-align: center; }
     div.Pp { margin: 1ex 0ex; }
   </style>
-  <link rel="stylesheet" href="manual.css" type="text/css" media="all"/>
+  <link rel="stylesheet" href="mandoc.css" type="text/css" media="all"/>
   <title>RGBLINK(1)</title>
 </head>
 <body>
@@ -82,7 +82,7 @@ The arguments are as follows:
     <var class="Ar" title="Ar">overlayfile</var></dt>
   <dd class="It-tag">The ROM image to overlay sections over. When an overlay ROM
       is provided, all sections must be fixed. This may be used to patch an
-      existing binray.</dd>
+      existing binary.</dd>
   <dt class="It-tag">&#x00A0;</dt>
   <dd class="It-tag">&#x00A0;</dd>
   <dt class="It-tag"><a class="selflink" href="#o"><b class="Fl" title="Fl" id="o">-o</b></a>

docs/rgblink.5.html

@@ -8,7 +8,7 @@
     td.head-vol { text-align: center; }
     div.Pp { margin: 1ex 0ex; }
   </style>
-  <link rel="stylesheet" href="manual.css" type="text/css" media="all"/>
+  <link rel="stylesheet" href="mandoc.css" type="text/css" media="all"/>
   <title>RGBLINK(5)</title>
 </head>
 <body>

include/asm/main.h

@@ -12,15 +12,16 @@
 #include <stdbool.h>
 #include <stdint.h>
 
-#include "extern/stdnoreturn.h"
+#include "helpers.h"
 
 struct sOptions {
-	char gbgfx[4];
 	char binary[2];
-	int32_t fillchar;
+	char gbgfx[4];
-	bool verbose;
-	bool haltnop;
 	bool exportall;
+	int32_t fillchar;
+	bool haltnop;
+	bool optimizeloads;
+	bool verbose;
 	bool warnings; /* True to enable warnings, false to disable them. */
 };
 
@@ -45,7 +46,7 @@ void opt_Parse(char *s);
  * It is also used when the assembler goes into an invalid state (for example,
  * when it fails to allocate memory).
  */
-noreturn void fatalerror(const char *fmt, ...);
+noreturn_ void fatalerror(const char *fmt, ...);
 
 /*
  * Used for errors that make it impossible to assemble correctly, but don't

include/extern/err.h

@@ -17,7 +17,7 @@
 
 #include <stdarg.h>
 
-#include "extern/stdnoreturn.h"
+#include "helpers.h"
 
 #define warn rgbds_warn
 #define vwarn rgbds_vwarn
@@ -34,10 +34,10 @@ void vwarn(const char *fmt, va_list ap);
 void warnx(const char *fmt, ...);
 void vwarnx(const char *fmt, va_list ap);
 
-noreturn void err(int status, const char *fmt, ...);
+noreturn_ void err(int status, const char *fmt, ...);
-noreturn void verr(int status, const char *fmt, va_list ap);
+noreturn_ void verr(int status, const char *fmt, va_list ap);
-noreturn void errx(int status, const char *fmt, ...);
+noreturn_ void errx(int status, const char *fmt, ...);
-noreturn void verrx(int status, const char *fmt, va_list ap);
+noreturn_ void verrx(int status, const char *fmt, va_list ap);
 
 #endif /* ERR_IN_LIBC */
 

include/extern/stdnoreturn.h

@@ -1,29 +0,0 @@
-/*
- * This file is part of RGBDS.
- *
- * Copyright (c) 2014-2018, RGBDS contributors.
- *
- * SPDX-License-Identifier: MIT
- */
-
-#ifndef EXTERN_STDNORETURN_H
-#define EXTERN_STDNORETURN_H
-
-#if __STDC_VERSION__ >= 201112L
-	/* C11 or newer */
-	#define noreturn _Noreturn
-#elif __cplusplus >= 201103L
-	/* C++11 or newer */
-	#define noreturn [[noreturn]]
-#elif __GNUC__ > 2 || (__GNUC__ == 2 && (__GNUC_MINOR__ >= 5))
-	/* GCC 2.5 or newer */
-	#define noreturn __attribute__ ((noreturn))
-#elif _MSC_VER >= 1310
-	/* MS Visual Studio 2003/.NET Framework 1.1 or newer */
-	#define noreturn _declspec(noreturn)
-#else
-	/* Unsupported, but no need to throw a fit */
-	#define noreturn
-#endif
-
-#endif /* EXTERN_STDNORETURN_H */

include/gfx/gb.h

@@ -12,14 +12,15 @@
 #include <stdint.h>
 #include "gfx/main.h"
 
-void png_to_gb(const struct PNGImage png, struct GBImage *gb);
+void raw_to_gb(const struct RawIndexedImage *raw_image, struct GBImage *gb);
-void output_file(const struct Options opts, const struct GBImage gb);
+void output_file(const struct Options *opts, const struct GBImage *gb);
 int get_tile_index(uint8_t *tile, uint8_t **tiles, int num_tiles,
 		   int tile_size);
-void create_tilemap(const struct Options opts, struct GBImage *gb,
+void create_tilemap(const struct Options *opts, struct GBImage *gb,
 		    struct Tilemap *tilemap);
-void output_tilemap_file(const struct Options opts,
+void output_tilemap_file(const struct Options *opts,
-			 const struct Tilemap tilemap);
+			 const struct Tilemap *tilemap);
-void output_palette_file(const struct Options opts, const struct PNGImage png);
+void output_palette_file(const struct Options *opts,
+			 const struct RawIndexedImage *raw_image);
 
 #endif

include/gfx/main.h

@@ -31,6 +31,21 @@ struct Options {
 	char *infile;
 };
 
+struct RGBColor {
+	uint8_t red;
+	uint8_t green;
+	uint8_t blue;
+};
+
+struct ImageOptions {
+	bool horizontal;
+	int trim;
+	char *mapfile;
+	bool mapout;
+	char *palfile;
+	bool palout;
+};
+
 struct PNGImage {
 	png_struct *png;
 	png_info *info;
@@ -39,12 +54,14 @@ struct PNGImage {
 	int height;
 	png_byte depth;
 	png_byte type;
-	bool horizontal;
+};
-	int trim;
+
-	char *mapfile;
+struct RawIndexedImage {
-	bool mapout;
+	uint8_t **data;
-	char *palfile;
+	struct RGBColor *palette;
-	bool palout;
+	int num_colors;
+	int width;
+	int height;
 };
 
 struct GBImage {

include/gfx/makepng.h

@@ -11,10 +11,11 @@
 
 #include "gfx/main.h"
 
-void input_png_file(const struct Options opts, struct PNGImage *img);
+struct RawIndexedImage *input_png_file(const struct Options *opts,
-void get_text(struct PNGImage *png);
+				       struct ImageOptions *png_options);
-void set_text(const struct PNGImage *png);
+void output_png_file(const struct Options *opts,
-void output_png_file(const struct Options opts, const struct PNGImage *png);
+		     const struct ImageOptions *png_options,
-void free_png_data(const struct PNGImage *png);
+		     const struct RawIndexedImage *raw_image);
+void destroy_raw_image(struct RawIndexedImage **raw_image_ptr_ptr);
 
 #endif /* RGBDS_GFX_PNG_H */

include/helpers.h

@@ -0,0 +1,22 @@
+/*
+ * This file is part of RGBDS.
+ *
+ * Copyright (c) 2014-2018, RGBDS contributors.
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#ifndef HELPERS_H
+#define HELPERS_H
+
+#ifdef __GNUC__
+	/* GCC or compatible */
+	#define noreturn_	__attribute__ ((noreturn))
+	#define unused_		__attribute__ ((unused))
+#else
+	/* Unsupported, but no need to throw a fit */
+	#define noreturn_
+	#define unused_
+#endif
+
+#endif /* HELPERS_H */

include/link/script.h

@@ -11,9 +11,9 @@
 
 #include <stdint.h>
 
-#include "extern/stdnoreturn.h"
+#include "helpers.h"
 
-noreturn void script_fatalerror(const char *fmt, ...);
+noreturn_ void script_fatalerror(const char *fmt, ...);
 
 void script_Parse(const char *path);
 

include/linkdefs.h

@@ -66,7 +66,8 @@ enum eSymbolType {
 enum ePatchType {
 	PATCH_BYTE	= 0x00,
 	PATCH_WORD_L	= 0x01,
-	PATCH_LONG_L	= 0x02
+	PATCH_LONG_L	= 0x02,
+	PATCH_BYTE_JR	= 0x03
 };
 
 #endif /* RGBDS_LINKDEFS_H */

include/version.h

@@ -11,7 +11,7 @@
 
 #define PACKAGE_VERSION_MAJOR (0)
 #define PACKAGE_VERSION_MINOR (3)
-#define PACKAGE_VERSION_PATCH (5)
+#define PACKAGE_VERSION_PATCH (7)
 
 const char *get_package_version_string(void);
 

src/asm/asmy.y

@@ -28,8 +28,10 @@
 #include "common.h"
 #include "linkdefs.h"
 
+uint32_t nListCountEmpty;
 char *tzNewMacro;
 uint32_t ulNewMacroSize;
+int32_t nPCOffset;
 
 static void bankrangecheck(char *name, uint32_t secttype, int32_t org,
 			   int32_t bank)
@@ -339,8 +341,9 @@ static void if_skip_to_else(void)
 				break;
 
 			case '\"':
-				src++;
+				src += 2;
 				inString = false;
+				break;
 
 			default:
 				src++;
@@ -455,7 +458,6 @@ static void updateUnion(void)
 %type	<nConstValue>	const_3bit
 %type	<sVal>		const_8bit
 %type	<sVal>		const_16bit
-%type	<sVal>		const_PCrel
 %type	<nConstValue>	sectiontype
 
 %type	<tzString>	string
@@ -504,7 +506,7 @@ static void updateUnion(void)
 %token	<tzSym> T_POP_SET
 %token	<tzSym> T_POP_EQUS
 
-%token	T_POP_INCLUDE T_POP_PRINTF T_POP_PRINTT T_POP_PRINTV
+%token	T_POP_INCLUDE T_POP_PRINTF T_POP_PRINTT T_POP_PRINTV T_POP_PRINTI
 %token	T_POP_IF T_POP_ELIF T_POP_ELSE T_POP_ENDC
 %token	T_POP_IMPORT T_POP_EXPORT T_POP_GLOBAL
 %token	T_POP_DB T_POP_DS T_POP_DW T_POP_DL
@@ -580,10 +582,13 @@ asmfile		: lines;
 
 /* Note: The lexer adds '\n' at the end of the input */
 lines		: /* empty */
-		| lines line '\n' {
+		| lines {
-			nLineNo += 1;
+				nListCountEmpty = 0;
-			nTotalLines += 1;
+				nPCOffset = 1;
-		}
+			} line '\n' {
+				nLineNo += 1;
+				nTotalLines += 1;
+			}
 ;
 
 line		: label
@@ -648,6 +653,7 @@ simple_pseudoop : include
 		| printf
 		| printt
 		| printv
+		| printi
 		| if
 		| elif
 		| else
@@ -655,9 +661,9 @@ simple_pseudoop : include
 		| import
 		| export
 		| global
-		| db
+		| { nPCOffset = 0; } db
-		| dw
+		| { nPCOffset = 0; } dw
-		| dl
+		| { nPCOffset = 0; } dl
 		| ds
 		| section
 		| rsreset
@@ -802,16 +808,28 @@ ds		: T_POP_DS uconst
 		}
 ;
 
-db		: T_POP_DB constlist_8bit_entry comma constlist_8bit
+db		: T_POP_DB constlist_8bit_entry comma constlist_8bit {
-		| T_POP_DB constlist_8bit_entry_single
+			if ((nPass == 1) && (nListCountEmpty > 0)) {
+				warning("Empty entry in list of 8-bit elements (treated as 0).");
+			}
+		}
+		| T_POP_DB constlist_8bit_entry
 ;
 
-dw		: T_POP_DW constlist_16bit_entry comma constlist_16bit
+dw		: T_POP_DW constlist_16bit_entry comma constlist_16bit {
-		| T_POP_DW constlist_16bit_entry_single
+			if ((nPass == 1) && (nListCountEmpty > 0)) {
+				warning("Empty entry in list of 16-bit elements (treated as 0).");
+			}
+		}
+		| T_POP_DW constlist_16bit_entry
 ;
 
-dl		: T_POP_DL constlist_32bit_entry comma constlist_32bit
+dl		: T_POP_DL constlist_32bit_entry comma constlist_32bit {
-		| T_POP_DL constlist_32bit_entry_single
+			if ((nPass == 1) && (nListCountEmpty > 0)) {
+				warning("Empty entry in list of 32-bit elements (treated as 0).");
+			}
+		}
+		| T_POP_DL constlist_32bit_entry
 ;
 
 purge		: T_POP_PURGE {
@@ -933,6 +951,13 @@ printv		: T_POP_PRINTV const
 		}
 ;
 
+printi		: T_POP_PRINTI const
+		{
+			if (nPass == 1)
+				printf("%d", $2);
+		}
+;
+
 printf		: T_POP_PRINTF const
 		{
 			if (nPass == 1)
@@ -1021,26 +1046,7 @@ constlist_8bit	: constlist_8bit_entry
 constlist_8bit_entry : /* empty */
 		{
 			out_Skip(1);
-			if (nPass == 1)
+			nListCountEmpty++;
-				warning("Empty entry in list of 8-bit elements (treated as 0).");
-		}
-		| const_8bit
-		{
-			out_RelByte(&$1);
-		}
-		| string
-		{
-			char *s = $1;
-			int32_t length = charmap_Convert(&s);
-
-			out_AbsByteGroup(s, length);
-			free(s);
-		}
-;
-
-constlist_8bit_entry_single : /* empty */
-		{
-			out_Skip(1);
 		}
 		| const_8bit
 		{
@@ -1063,18 +1069,7 @@ constlist_16bit : constlist_16bit_entry
 constlist_16bit_entry : /* empty */
 		{
 			out_Skip(2);
-			if (nPass == 1)
+			nListCountEmpty++;
-				warning("Empty entry in list of 16-bit elements (treated as 0).");
-		}
-		| const_16bit
-		{
-			out_RelWord(&$1);
-		}
-;
-
-constlist_16bit_entry_single : /* empty */
-		{
-			out_Skip(2);
 		}
 		| const_16bit
 		{
@@ -1089,8 +1084,7 @@ constlist_32bit : constlist_32bit_entry
 constlist_32bit_entry : /* empty */
 		{
 			out_Skip(4);
-			if (nPass == 1)
+			nListCountEmpty++;
-				warning("Empty entry in list of 32-bit elements (treated as 0).");
 		}
 		| relocconst
 		{
@@ -1098,24 +1092,6 @@ constlist_32bit_entry : /* empty */
 		}
 ;
 
-constlist_32bit_entry_single : /* empty */
-		{
-			out_Skip(4);
-		}
-		| relocconst
-		{
-			out_RelLong(&$1);
-		}
-;
-
-const_PCrel	: relocconst
-		{
-			if (!rpn_isPCRelative(&$1))
-				yyerror("Expression must be PC-relative");
-			$$ = $1;
-		}
-;
-
 const_8bit	: relocconst
 		{
 			if( (!rpn_isReloc(&$1)) && (($1.nVal < -128) || ($1.nVal > 255)) )
@@ -1135,8 +1111,39 @@ const_16bit	: relocconst
 
 relocconst	: T_ID
 		{
-			rpn_Symbol(&$$, $1);
+			/*
-			$$.nVal = sym_GetValue($1);
+			 * The value of @ needs to be evaluated by the linker,
+			 * it can only be calculated by the assembler in very
+			 * few cases (when the base address of a section is
+			 * known).
+			 *
+			 * '@' is a bit special in that it means different
+			 * things depending on when it is used:
+			 *
+			 * - JR/LD/ADD/etc: It refers to the first byte of the
+			 *   instruction (1 byte offset relative to the value
+			 *   stored in the ROM).
+			 * - DB/DW/DL: It refers to the address of the value
+			 *   that is being saved (0 byte offset relative to the
+			 *   value stored in the ROM.
+			 *
+			 * This offset must be added whenever '@' is added to a
+			 * RPN expression so that the linker can calculate the
+			 * correct result of any expression that uses '@'.
+			 */
+			if ((strcmp($1, "@") == 0) && (nPCOffset != 0)) {
+				struct Expression sTemp, sOffset;
+
+				rpn_Symbol(&sTemp, $1);
+				sTemp.nVal = sym_GetValue($1);
+
+				rpn_Number(&sOffset, nPCOffset);
+
+				rpn_SUB(&$$, &sTemp, &sOffset);
+			} else {
+				rpn_Symbol(&$$, $1);
+				$$.nVal = sym_GetValue($1);
+			}
 		}
 		| T_NUMBER
 		{
@@ -1234,6 +1241,8 @@ uconst		: const
 
 const		: T_ID					{ $$ = sym_GetConstantValue($1); }
 		| T_NUMBER				{ $$ = $1; }
+		| T_OP_HIGH '(' const ')'		{ $$ = ($3 >> 8) & 0xFF; }
+		| T_OP_LOW '(' const ')'		{ $$ = $3 & 0xFF; }
 		| string				{ $$ = str2int($1); }
 		| T_OP_LOGICNOT const %prec NEG		{ $$ = !$2; }
 		| const T_OP_LOGICOR const		{ $$ = $1 || $3; }
@@ -1255,19 +1264,38 @@ const		: T_ID					{ $$ = sym_GetConstantValue($1); }
 		| const T_OP_XOR const			{ $$ = $1 ^ $3; }
 		| const T_OP_OR const			{ $$ = $1 | $3; }
 		| const T_OP_AND const			{ $$ = $1 & $3; }
-		| const T_OP_SHL const			{ $$ = $1 << $3; }
+		| const T_OP_SHL const
-		| const T_OP_SHR const			{ $$ = $1 >> $3; }
+		{
+			if ($1 < 0)
+				warning("Left shift of negative value: %d", $1);
+
+			if ($3 < 0)
+				fatalerror("Shift by negative value: %d", $3);
+			else if ($3 >= 32)
+				fatalerror("Shift by too big value: %d", $3);
+
+			$$ = $1 << $3;
+		}
+		| const T_OP_SHR const
+		{
+			if ($3 < 0)
+				fatalerror("Shift by negative value: %d", $3);
+			else if ($3 >= 32)
+				fatalerror("Shift by too big value: %d", $3);
+
+			$$ = $1 >> $3;
+		}
 		| const T_OP_MUL const			{ $$ = $1 * $3; }
 		| const T_OP_DIV const
 		{
 			if ($3 == 0)
-				fatalerror("division by zero");
+				fatalerror("Division by zero");
 			$$ = $1 / $3;
 		}
 		| const T_OP_MOD const
 		{
 			if ($3 == 0)
-				fatalerror("division by zero");
+				fatalerror("Division by zero");
 			$$ = $1 % $3;
 		}
 		| T_OP_ADD const %prec NEG		{ $$ = +$2; }
@@ -1311,26 +1339,37 @@ const		: T_ID					{ $$ = sym_GetConstantValue($1); }
 
 string		: T_STRING
 		{
-			strcpy($$, $1);
+			if (snprintf($$, MAXSTRLEN + 1, "%s", $1) > MAXSTRLEN)
+				warning("String is too long '%s'", $1);
 		}
 		| T_OP_STRSUB '(' string comma uconst comma uconst ')'
 		{
-			strncpy($$, $3 + $5 - 1, $7);
+			uint32_t len = $7;
-			$$[$7] = 0;
+			if (len > MAXSTRLEN) {
+				warning("STRSUB: Length too big: %u", len);
+				len = MAXSTRLEN;
+			}
+
+			if (snprintf($$, len + 1, "%s", $3 + $5 - 1) > MAXSTRLEN)
+				warning("STRSUB: String too long '%s'", $$);
 		}
 		| T_OP_STRCAT '(' string comma string ')'
 		{
-			strcpy($$, $3);
+			if (snprintf($$, MAXSTRLEN + 1, "%s%s", $3, $5) > MAXSTRLEN)
-			strcat($$, $5);
+				warning("STRCAT: String too long '%s%s'", $3, $5);
 		}
 		| T_OP_STRUPR '(' string ')'
 		{
-			strcpy($$, $3);
+			if (snprintf($$, MAXSTRLEN + 1, "%s", $3) > MAXSTRLEN)
+				warning("STRUPR: String too long '%s'", $3);
+
 			upperstring($$);
 		}
 		| T_OP_STRLWR '(' string ')'
 		{
-			strcpy($$, $3);
+			if (snprintf($$, MAXSTRLEN + 1, "%s", $3) > MAXSTRLEN)
+				warning("STRUPR: String too long '%s'", $3);
+
 			lowerstring($$);
 		}
 ;
@@ -1602,12 +1641,12 @@ z80_jp		: T_Z80_JP const_16bit
 		}
 ;
 
-z80_jr		: T_Z80_JR const_PCrel
+z80_jr		: T_Z80_JR const_16bit
 		{
 			out_AbsByte(0x18);
 			out_PCRelByte(&$2);
 		}
-		| T_Z80_JR ccode comma const_PCrel
+		| T_Z80_JR ccode comma const_16bit
 		{
 			out_AbsByte(0x20 | ($2 << 3));
 			out_PCRelByte(&$4);
@@ -1716,7 +1755,8 @@ z80_ld_mem	: T_Z80_LD op_mem_ind comma T_MODE_SP
 		}
 		| T_Z80_LD op_mem_ind comma T_MODE_A
 		{
-			if ((!rpn_isReloc(&$2)) && ($2.nVal >= 0xFF00)) {
+			if (CurrentOptions.optimizeloads &&
+			    (!rpn_isReloc(&$2)) && ($2.nVal >= 0xFF00)) {
 				out_AbsByte(0xE0);
 				out_AbsByte($2.nVal & 0xFF);
 			} else {
@@ -1769,7 +1809,8 @@ z80_ld_a	: T_Z80_LD reg_r comma T_MODE_C_IND
 		| T_Z80_LD reg_r comma op_mem_ind
 		{
 			if ($2 == REG_A) {
-				if ((!rpn_isReloc(&$4)) && ($4.nVal >= 0xFF00)) {
+				if (CurrentOptions.optimizeloads &&
+				    (!rpn_isReloc(&$4)) && ($4.nVal >= 0xFF00)) {
 					out_AbsByte(0xF0);
 					out_AbsByte($4.nVal & 0xFF);
 				} else {

src/asm/fstack.c

@@ -87,6 +87,8 @@ static void pushcontext(void)
 		(*ppFileStack)->nREPTBlockSize = nCurrentREPTBlockSize;
 		(*ppFileStack)->nREPTBlockCount = nCurrentREPTBlockCount;
 		break;
+	default:
+		fatalerror("%s: Internal error.", __func__);
 	}
 
 	nLineNo = 0;
@@ -152,6 +154,8 @@ static int32_t popcontext(void)
 		nCurrentREPTBlockSize = pLastFile->nREPTBlockSize;
 		nCurrentREPTBlockCount = pLastFile->nREPTBlockCount;
 		break;
+	default:
+		fatalerror("%s: Internal error.", __func__);
 	}
 
 	free(*ppLastFile);
@@ -174,6 +178,8 @@ int32_t fstk_GetLine(void)
 		return nLineNo; /* ??? */
 	case STAT_isREPTBlock:
 		break; /* Peek top file of the stack */
+	default:
+		fatalerror("%s: Internal error.", __func__);
 	}
 
 	pLastFile = pFileStack;
@@ -257,8 +263,10 @@ FILE *fstk_FindFile(char *fname)
 		 * space had been available. Thus, a return value of `size` or
 		 * more means that the output was truncated.
 		 */
-		if (snprintf(path, sizeof(path), "%s%s", IncludePaths[i], fname)
+		int fullpathlen = snprintf(path, sizeof(path), "%s%s",
-		    >= sizeof(path))
+					   IncludePaths[i], fname);
+
+		if (fullpathlen >= (int)sizeof(path))
 			continue;
 
 		f = fopen(path, "rb");
@@ -347,7 +355,7 @@ void fstk_RunMacroArg(int32_t s)
 
 	pushcontext();
 	nCurrentStatus = STAT_isMacroArg;
-	sprintf(tzCurrentFileName, "%c", (uint8_t)s);
+	snprintf(tzCurrentFileName, _MAX_PATH + 1, "%c", (uint8_t)s);
 	CurrentFlexHandle = yy_scan_bytes(sym, strlen(sym));
 	yy_switch_to_buffer(CurrentFlexHandle);
 }
@@ -410,7 +418,7 @@ void fstk_Init(char *s)
 
 	nMacroCount = 0;
 	nCurrentStatus = STAT_isInclude;
-	strcpy(tzCurrentFileName, tzFileName);
+	snprintf(tzCurrentFileName, _MAX_PATH + 1, "%s", tzFileName);
 	CurrentFlexHandle = yy_create_buffer(pCurrentFile);
 	yy_switch_to_buffer(CurrentFlexHandle);
 	nLineNo = 1;

src/asm/globlex.c

@@ -20,6 +20,8 @@
 #include "asm/symbol.h"
 #include "asm/symbol.h"
 
+#include "helpers.h"
+
 #include "asmy.h"
 
 bool oDontExpandStrings;
@@ -93,6 +95,9 @@ static int32_t ascii2bin(char *s)
 		s += 1;
 		convertfunc = binary2bin;
 		break;
+	default:
+		/* Handle below */
+		break;
 	}
 
 	if (radix == 4) {
@@ -216,7 +221,7 @@ uint32_t PutMacroArg(char *src, uint32_t size)
 	return 0;
 }
 
-uint32_t PutUniqueArg(char *src, uint32_t size)
+uint32_t PutUniqueArg(unused_ char *src, uint32_t size)
 {
 	char *s;
 
@@ -368,6 +373,7 @@ const struct sLexInitString lexer_strings[] = {
 
 	{"include", T_POP_INCLUDE},
 	{"printt", T_POP_PRINTT},
+	{"printi", T_POP_PRINTI},
 	{"printv", T_POP_PRINTV},
 	{"printf", T_POP_PRINTF},
 	{"export", T_POP_EXPORT},
@@ -578,7 +584,7 @@ void setup_lexer(void)
 	lex_FloatAddRange(id, '@', '@');
 	lex_FloatAddRange(id, '#', '#');
 
-	//@ID
+	// "@"
 
 	id = lex_FloatAlloc(&tIDToken);
 	lex_FloatAddFirstRange(id, '@', '@');

src/asm/lexer.c

@@ -159,6 +159,8 @@ YY_BUFFER_STATE yy_create_buffer(FILE *f)
 	pBuffer->pBuffer[size + 1] = 0;
 	pBuffer->nBufferSize = size + 1;
 
+	/* Convert all line endings to LF and spaces */
+
 	char *mem = pBuffer->pBuffer;
 	uint32_t instring = 0;
 
@@ -171,20 +173,44 @@ YY_BUFFER_STATE yy_create_buffer(FILE *f)
 		} else if (instring) {
 			mem += 1;
 		} else {
-			if ((mem[0] == 10 && mem[1] == 13)
+			/* LF CR and CR LF */
-				|| (mem[0] == 13 && mem[1] == 10)) {
+			if (((mem[0] == 10) && (mem[1] == 13))
+			 || ((mem[0] == 13) && (mem[1] == 10))) {
 				mem[0] = ' ';
 				mem[1] = '\n';
 				mem += 2;
-			} else if (mem[0] == 10 || mem[0] == 13) {
+			/* LF and CR */
+			} else if ((mem[0] == 10) || (mem[0] == 13)) {
 				mem[0] = '\n';
 				mem += 1;
-			} else if (mem[0] == '\n' && mem[1] == '*') {
+			} else {
 				mem += 1;
-				while (!(*mem == '\n' || *mem == '\0'))
+			}
+		}
+	}
+
+	/* Remove comments */
+
+	mem = pBuffer->pBuffer;
+	instring = 0;
+
+	while (*mem) {
+		if (*mem == '\"')
+			instring = 1 - instring;
+
+		if ((mem[0] == '\\') && (mem[1] == '\"' || mem[1] == '\\')) {
+			mem += 2;
+		} else if (instring) {
+			mem += 1;
+		} else {
+			/* Comments that start with ; anywhere in a line */
+			if (*mem == ';') {
+				while (!((*mem == '\n') || (*mem == '\0')))
 					*mem++ = ' ';
-			} else if (*mem == ';') {
+			/* Comments that start with * at the start of a line */
-				while (!(*mem == '\n' || *mem == '\0'))
+			} else if ((mem[0] == '\n') && (mem[1] == '*')) {
+				mem += 1;
+				while (!((*mem == '\n') || (*mem == '\0')))
 					*mem++ = ' ';
 			} else {
 				mem += 1;
@@ -388,7 +414,7 @@ void yylex_GetFloatMaskAndFloatLen(uint32_t *pnFloatMask, uint32_t *pnFloatLen)
 /*
  * Gets the longest keyword/operator from the current position in the buffer.
  */
-struct sLexString *yylex_GetLongestFixed()
+struct sLexString *yylex_GetLongestFixed(void)
 {
 	struct sLexString *pLongestFixed = NULL;
 	char *s = pLexBuffer;
@@ -612,6 +638,43 @@ scanagain:
 		}
 	}
 
+	/* Check for line continuation character */
+	if (*pLexBuffer == '\\') {
+		/*
+		 * Look for line continuation character after a series of
+		 * spaces. This is also useful for files that use Windows line
+		 * endings: "\r\n" is replaced by " \n" before the lexer has the
+		 * opportunity to see it.
+		 */
+		if (pLexBuffer[1] == ' ') {
+			pLexBuffer += 2;
+			while (1) {
+				if (*pLexBuffer == ' ') {
+					pLexBuffer++;
+				} else if (*pLexBuffer == '\n') {
+					pLexBuffer++;
+					nLineNo += 1;
+					goto scanagain;
+				} else {
+					errx(1, "Expected a new line after the continuation character.");
+				}
+			}
+		}
+
+		/* Line continuation character */
+		if (pLexBuffer[1] == '\n') {
+			pLexBuffer += 2;
+			nLineNo += 1;
+			goto scanagain;
+		}
+
+		/*
+		 * If there isn't a newline character or a space, ignore the
+		 * character '\'. It will eventually be handled by other
+		 * functions like PutMacroArg().
+		 */
+	}
+
 	/*
 	 * Try to match an identifier, macro argument (e.g. \1),
 	 * or numeric literal.
@@ -699,6 +762,9 @@ static uint32_t yylex_MACROARGS(void)
 			case '\\':
 				ch = '\\';
 				break;
+			case '"':
+				ch = '\"';
+				break;
 			case ',':
 				ch = ',';
 				break;
@@ -708,6 +774,32 @@ static uint32_t yylex_MACROARGS(void)
 			case '}':
 				ch = '}';
 				break;
+			case ' ':
+				/*
+				 * Look for line continuation character after a
+				 * series of spaces. This is also useful for
+				 * files that use Windows line endings: "\r\n"
+				 * is replaced by " \n" before the lexer has the
+				 * opportunity to see it.
+				 */
+				while (1) {
+					if (*pLexBuffer == ' ') {
+						pLexBuffer++;
+					} else if (*pLexBuffer == '\n') {
+						pLexBuffer++;
+						nLineNo += 1;
+						ch = 0;
+						break;
+					} else {
+						errx(1, "Expected a new line after the continuation character.");
+					}
+				}
+				break;
+			case '\n':
+				/* Line continuation character */
+				nLineNo += 1;
+				ch = 0;
+				break;
 			default:
 				maxLength = MAXSTRLEN - index;
 				length = CopyMacroArg(&yylval.tzString[index],
@@ -758,7 +850,7 @@ uint32_t yylex(void)
 		return yylex_NORMAL();
 	case LEX_STATE_MACROARGS:
 		return yylex_MACROARGS();
+	default:
+		fatalerror("%s: Internal error.", __func__);
 	}
-
-	fatalerror("Internal error in %s", __func__);
 }

src/asm/main.c

@@ -6,6 +6,7 @@
  * SPDX-License-Identifier: MIT
  */
 
+#include <float.h>
 #include <math.h>
 #include <stdarg.h>
 #include <stdio.h>
@@ -23,6 +24,7 @@
 
 #include "extern/err.h"
 
+#include "helpers.h"
 #include "version.h"
 
 extern int yyparse(void);
@@ -147,10 +149,13 @@ void opt_Parse(char *s)
 	case 'z':
 		if (strlen(&s[1]) <= 2) {
 			int32_t result;
+			unsigned int fillchar;
 
-			result = sscanf(&s[1], "%x", &newopt.fillchar);
+			result = sscanf(&s[1], "%x", &fillchar);
 			if (!((result == EOF) || (result == 1)))
 				errx(1, "Invalid argument for option 'z'");
+
+			newopt.fillchar = fillchar;
 		} else {
 			errx(1, "Invalid argument for option 'z'");
 		}
@@ -222,7 +227,7 @@ void opt_AddDefine(char *s)
 
 static void opt_ParseDefines(void)
 {
-	int32_t i;
+	uint32_t i;
 
 	for (i = 0; i < cldefines_index; i += 2)
 		sym_AddString(cldefines[i], cldefines[i + 1]);
@@ -235,7 +240,7 @@ void verror(const char *fmt, va_list args)
 {
 	fprintf(stderr, "ERROR: ");
 	fstk_Dump();
-	fprintf(stderr, ":\n\t");
+	fprintf(stderr, ":\n    ");
 	vfprintf(stderr, fmt, args);
 	fprintf(stderr, "\n");
 	nErrors += 1;
@@ -250,7 +255,7 @@ void yyerror(const char *fmt, ...)
 	va_end(args);
 }
 
-void fatalerror(const char *fmt, ...)
+noreturn_ void fatalerror(const char *fmt, ...)
 {
 	va_list args;
 
@@ -272,7 +277,7 @@ void warning(const char *fmt, ...)
 
 	fprintf(stderr, "warning: ");
 	fstk_Dump();
-	fprintf(stderr, ":\n\t");
+	fprintf(stderr, ":\n    ");
 	vfprintf(stderr, fmt, args);
 	fprintf(stderr, "\n");
 
@@ -282,7 +287,7 @@ void warning(const char *fmt, ...)
 static void print_usage(void)
 {
 	printf(
-"usage: rgbasm [-EhVvw] [-b chars] [-Dname[=value]] [-g chars] [-i path]\n"
+"usage: rgbasm [-EhLVvw] [-b chars] [-Dname[=value]] [-g chars] [-i path]\n"
 "              [-M dependfile] [-o outfile] [-p pad_value] file.asm\n");
 	exit(1);
 }
@@ -316,17 +321,18 @@ int main(int argc, char *argv[])
 	DefaultOptions.gbgfx[3] = '3';
 	DefaultOptions.binary[0] = '0';
 	DefaultOptions.binary[1] = '1';
-	DefaultOptions.fillchar = 0;
-	DefaultOptions.verbose = false;
-	DefaultOptions.haltnop = true;
 	DefaultOptions.exportall = false;
+	DefaultOptions.fillchar = 0;
+	DefaultOptions.optimizeloads = true;
+	DefaultOptions.haltnop = true;
+	DefaultOptions.verbose = false;
 	DefaultOptions.warnings = true;
 
 	opt_SetCurrentOptions(&DefaultOptions);
 
 	newopt = CurrentOptions;
 
-	while ((ch = getopt(argc, argv, "b:D:g:hi:M:o:p:EVvw")) != -1) {
+	while ((ch = getopt(argc, argv, "b:D:Eg:hi:LM:o:p:Vvw")) != -1) {
 		switch (ch) {
 		case 'b':
 			if (strlen(optarg) == 2) {
@@ -358,6 +364,9 @@ int main(int argc, char *argv[])
 		case 'i':
 			fstk_AddIncludePath(optarg);
 			break;
+		case 'L':
+			newopt.optimizeloads = false;
+			break;
 		case 'M':
 			dependfile = fopen(optarg, "w");
 			if (dependfile == NULL)
@@ -476,7 +485,7 @@ int main(int argc, char *argv[])
 	if (CurrentOptions.verbose) {
 		printf("Success! %u lines in %d.%02d seconds ", nTotalLines,
 		       (int)timespent, ((int)(timespent * 100.0)) % 100);
-		if (timespent == 0)
+		if (timespent < FLT_MIN_EXP)
 			printf("(INFINITY lines/minute)\n");
 		else
 			printf("(%d lines/minute)\n",

src/asm/output.c

@@ -593,7 +593,7 @@ void out_SetFileName(char *s)
 }
 
 /*
- * Find a section by name and type.  If it doesn't exist, create it
+ * Find a section by name and type. If it doesn't exist, create it
  */
 struct Section *out_FindSection(char *pzName, uint32_t secttype, int32_t org,
 				int32_t bank, int32_t alignment)
@@ -764,7 +764,7 @@ void out_String(char *s)
 }
 
 /*
- * Output a relocatable byte.  Checking will be done to see if it
+ * Output a relocatable byte. Checking will be done to see if it
  * is an absolute value in disguise.
  */
 void out_RelByte(struct Expression *expr)
@@ -803,7 +803,7 @@ void out_AbsWord(int32_t b)
 }
 
 /*
- * Output a relocatable word.  Checking will be done to see if
+ * Output a relocatable word. Checking will be done to see if
  * it's an absolute value in disguise.
  */
 void out_RelWord(struct Expression *expr)
@@ -847,7 +847,7 @@ void out_AbsLong(int32_t b)
 }
 
 /*
- * Output a relocatable longword.  Checking will be done to see if
+ * Output a relocatable longword. Checking will be done to see if
  * is an absolute value in disguise.
  */
 void out_RelLong(struct Expression *expr)
@@ -875,19 +875,23 @@ void out_RelLong(struct Expression *expr)
 }
 
 /*
- * Output a PC-relative byte
+ * Output a PC-relative relocatable byte. Checking will be done to see if it
+ * is an absolute value in disguise.
  */
 void out_PCRelByte(struct Expression *expr)
 {
-	int32_t b = expr->nVal;
-
 	checkcodesection();
 	checksectionoverflow(1);
-	b = (b & 0xFFFF) - (nPC + 1);
-	if (nPass == 2 && (b < -128 || b > 127))
-		yyerror("PC-relative value must be 8-bit");
 
-	out_AbsByte(b);
+	/* Always let the linker calculate the offset. */
+	if (nPass == 2) {
+		pCurrentSection->tData[nPC] = 0;
+		createpatch(PATCH_BYTE_JR, expr);
+	}
+	pCurrentSection->nPC += 1;
+	nPC += 1;
+	pPCSymbol->nValue += 1;
+
 	rpn_Reset(expr);
 }
 

src/asm/rgbasm.1

@@ -5,7 +5,7 @@
 .\"
 .\" SPDX-License-Identifier: MIT
 .\"
-.Dd January 26, 2018
+.Dd February 24, 2018
 .Dt RGBASM 1
 .Os RGBDS Manual
 .Sh NAME
@@ -13,7 +13,7 @@
 .Nd Game Boy assembler
 .Sh SYNOPSIS
 .Nm rgbasm
-.Op Fl EhVvw
+.Op Fl EhLVvw
 .Op Fl b Ar chars
 .Op Fl D Ar name Ns Op = Ns Ar value
 .Op Fl g Ar chars
@@ -55,6 +55,12 @@ The
 option disables this behavior.
 .It Fl i Ar path
 Add an include path.
+.It Fl L
+Disable the optimization that turns loads of the form
+.Sy LD [$FF00+n8],A
+into the opcode
+.Sy LDH [$FF00+n8],A
+in order to have full control of the result in the final ROM.
 .It Fl M Ar dependfile
 Print
 .Xr make 1
@@ -75,7 +81,9 @@ Disable warning output.
 .Sh EXAMPLES
 Assembling a basic source file is simple:
 .Pp
-.D1 $ rgbasm -o bar.o foo.asm
+.Bd -literal -offset indent
+$ rgbasm -o bar.o foo.asm
+.Ed
 .Pp
 The resulting object file is not yet a usable ROM image \(em it must first be
 run through

src/asm/rgbasm.5

@@ -5,7 +5,7 @@
 .\"
 .\" SPDX-License-Identifier: MIT
 .\"
-.Dd January 27, 2018
+.Dd March 13, 2018
 .Dt RGBASM 5
 .Os RGBDS Manual
 .Sh NAME
@@ -26,16 +26,46 @@ one instruction or pseudo‐op per line:
 .Pp
 Example:
 .Pp
-.Dl John: ld a,87 ;Weee
+.Bd -literal -offset indent
+John: ld a,87 ;Weee
+.Ed
 .Pp
 All pseudo‐ops, mnemonics and registers (reserved keywords) are case‐insensitive
 and all labels are case‐sensitive.
+.Pp
+There are two syntaxes for comments. In both cases, a comment ends at the end of
+the line. The most common one is: anything that follows a semicolon
+\[dq]\&;\[dq] (that isn't inside a string) is a comment. There is another
+format: anything that follows a \[dq]*\[dq] that is placed right at the start of
+a line is a comment. The assembler removes all comments from the code before
+doing anything else.
+.Pp
+Sometimes lines can be too long and it may be necessary to split them. The
+syntax to do so is the following one:
+.Pp
+.Bd -literal -offset indent
+    DB 1, 2, 3, 4 \[rs]
+       5, 6, 7, 8
+.Ed
+.Pp
+This works anywhere in the code except inside of strings. To split strings it is
+needed to use
+.Sy STRCAT
+like this:
+.Pp
+.Bd -literal -offset indent
+    DB STRCAT("Hello ", \[rs]
+              "world!")
+.Ed
+.Pp
 .Ss Sections
 Before you can start writing code, you must define a section.
 This tells the assembler what kind of information follows and, if it is code,
 where to put it.
 .Pp
-.Dl SECTION \[dq]CoolStuff\[dq],ROMX
+.Bd -literal -offset indent
+    SECTION \[dq]CoolStuff\[dq],ROMX
+.Ed
 .Pp
 This switches to the section called "CoolStuff" (or creates it if it doesn't
 already exist) and it defines it as a code section.
@@ -104,7 +134,13 @@ and
 .Sy LDH A,[$FF00+n8]
 syntax instead.
 This forces the assembler to emit the correct instruction and the linker to
-check if the value is in the correct range.
+check if the value is in the correct range. This optimization can be disabled
+by passing the
+.Fl L
+flag to
+.Sy rgbasm
+as explained in
+.Xr rgbasm 1 .
 .El
 .Pp
 A section is usually defined as a floating one, but the code can restrict where
@@ -116,22 +152,30 @@ obligation to follow any specific rules.
 The following example defines a section that can be placed anywhere in any ROMX
 bank:
 .Pp
-.Dl SECTION \[dq]CoolStuff\[dq],ROMX
+.Bd -literal -offset indent
+    SECTION \[dq]CoolStuff\[dq],ROMX
+.Ed
 .Pp
 If it is needed, the following syntax can be used to fix the base address of the
 section:
 .Pp
-.Dl SECTION \[dq]CoolStuff\[dq],ROMX[$4567]
+.Bd -literal -offset indent
+    SECTION \[dq]CoolStuff\[dq],ROMX[$4567]
+.Ed
 .Pp
 It won't, however, fix the bank number, which is left to the linker.
 If you also want to specify the bank you can do:
 .Pp
-.Dl SECTION \[dq]CoolStuff\[dq],ROMX[$4567],BANK[3]
+.Bd -literal -offset indent
+    SECTION \[dq]CoolStuff\[dq],ROMX[$4567],BANK[3]
+.Ed
 .Pp
 And if you only want to force the section into a certain bank, and not it's
 position within the bank, that's also possible:
 .Pp
-.Dl SECTION \[dq]CoolStuff\[dq],ROMX,BANK[7]
+.Bd -literal -offset indent
+    SECTION \[dq]CoolStuff\[dq],ROMX,BANK[7]
+.Ed
 .Pp
 In addition, you can specify byte alignment for a section.
 This ensures that the section starts at a memory address where the given number
@@ -143,9 +187,11 @@ However, if an alignment is specified, the base address must be left unassigned.
 This can be useful when using DMA to copy data or when it is needed to align the
 start of an array to 256 bytes to optimize the code that accesses it.
 .Pp
-.Dl SECTION \[dq]OAM Data\[dq],WRAM0,ALIGN[8] ; align to 256 bytes
+.Bd -literal -offset indent
-.Pp
+    SECTION \[dq]OAM Data\[dq],WRAM0,ALIGN[8] ; align to 256 bytes
-.Dl SECTION \[dq]VRAM Data\[dq],ROMX,BANK[2],ALIGN[4] ; align to 16 bytes
+
+    SECTION \[dq]VRAM Data\[dq],ROMX,BANK[2],ALIGN[4] ; align to 16 bytes
+.Ed
 .Pp
 HINT: If you think this is a lot of typing for doing a simple
 .Ic ORG
@@ -243,8 +289,10 @@ EQUates are constant symbols.
 They can, for example, be used for things such as bit-definitions of hardware
 registers.
 .Pp
-.Dl EXIT_OK      EQU $00
+.Bd -literal -offset indent
-.Dl EXIT_FAILURE EQU $01
+EXIT_OK      EQU $00
+EXIT_FAILURE EQU $01
+.Ed
 .Pp
 Note that a colon (:) following the label-name is not allowed.
 EQUates cannot be exported and imported.
@@ -266,7 +314,9 @@ Note that a colon (:) following the label-name is not allowed.
 SETs cannot be exported and imported.
 Alternatively you can use = as a synonym for SET.
 .Pp
-.Dl COUNT = 2
+.Bd -literal -offset indent
+COUNT = 2
+.Ed
 .Pp
 .It Sy RSSET , RSRESET , RB , RW
 .Pp
@@ -318,10 +368,10 @@ If you are familiar with C you can think of it as the same as #define.
 .Pp
 .Bd -literal -offset indent
 COUNTREG EQUS "[hl+]"
-ld a,COUNTREG
+    ld a,COUNTREG
 
 PLAYER_NAME EQUS \[dq]\[rs]\[dq]John\[rs]\[dq]\[dq]
-db PLAYER_NAME
+    db PLAYER_NAME
 .Ed
 .Pp
 Note that : following the label-name is not allowed, and that strings must be
@@ -329,12 +379,16 @@ quoted to be useful.
 .Pp
 This will be interpreted as:
 .Pp
-.Dl ld a,[hl+]
+.Bd -literal -offset indent
-.Dl db \[dq]John\[dq]
+    ld a,[hl+]
+    db \[dq]John\[dq]
+.Ed
 .Pp
 String-symbols can also be used to define small one-line macros:
 .Pp
-.Dl PUSHA EQUS \[dq]push af\[rs]npush bc\[rs]npush de\[rs]npush hl\[rs]n\[dq]
+.Bd -literal -offset indent
+PUSHA EQUS \[dq]push af\[rs]npush bc\[rs]npush de\[rs]npush hl\[rs]n\[dq]
+.Ed
 .Pp
 Note that a colon (:) following the label-name is not allowed.
 String equates can't be exported or imported.
@@ -447,7 +501,9 @@ Now I can call the macro specifying two arguments.
 The first being the address and the second being a bytecount.
 The macro will then reset all bytes in this range.
 .Pp
-.Dl LoopyMacro MyVars,54
+.Bd -literal -offset indent
+LoopyMacro MyVars,54
+.Ed
 .Pp
 Arguments are passed as string equates.
 There's no need to enclose them in quotes.
@@ -467,6 +523,19 @@ In reality, up to 256 arguments can be passed to a macro, but you can only use
 the first 9 like this. If you want to use the rest, you need to use the keyword
 .Ic SHIFT .
 .Pp
+Line continuations work as usual inside macros or lists of arguments of macros.
+Strings, however, are a bit trickier. The following example shows how to use
+strings as arguments for a macro:
+.Pp
+.Bd -literal -offset indent
+PrintMacro : MACRO
+    PRINTT \[rs]1
+ENDM
+
+    PrintMacro STRCAT(\[rs]\[dq]Hello\[rs]\[dq]\[rs],  \[rs]
+                      \[rs]\[dq] world\[rs]\[rs]n\[rs]\[dq])
+.Ed
+.Pp
 .Ic SHIFT
 is a special command only available in macros.
 Very useful in REPT-blocks.
@@ -553,7 +622,9 @@ The following symbols are defined by the assembler:
 defines a list of bytes that will be stored in the final image.
 Ideal for tables and text (which is not zero-terminated).
 .Pp
-.Dl DB 1,2,3,4,\[dq]This is a string\[dq]
+.Bd -literal -offset indent
+DB 1,2,3,4,\[dq]This is a string\[dq]
+.Ed
 .Pp
 Alternatively, you can use
 .Ic DW
@@ -597,7 +668,9 @@ and
 .Ic DL
 without any arguments instead.
 .Pp
-.Dl DS str_SIZEOF ;allocate str_SIZEOF bytes
+.Bd -literal -offset indent
+DS str_SIZEOF ;allocate str_SIZEOF bytes
+.Ed
 .Pp
 .Ss Including binary files
 You probably have some graphics you'd like to include.
@@ -607,15 +680,19 @@ to include a raw binary file as it is.
 If the file isn't found in the current directory, the include-path list passed
 to the linker on the command line will be searched.
 .Pp
-.Dl INCBIN \[dq]titlepic.bin\[dq]
+.Bd -literal -offset indent
-.Dl INCBIN \[dq]sprites/hero.bin\[dq]\ ; UNIX
+INCBIN \[dq]titlepic.bin\[dq]
-.Dl INCBIN \[dq]sprites\[rs]\[rs]hero.bin\[dq]\ ; Windows
+INCBIN \[dq]sprites/hero.bin\[dq]\ ; UNIX
+INCBIN \[dq]sprites\[rs]\[rs]hero.bin\[dq]\ ; Windows
+.Ed
 .Pp
 You can also include only part of a file with
 .Ic INCBIN .
 The example below includes 256 bytes from data.bin starting from byte 78.
 .Pp
-.Dl INCBIN \[dq]data.bin\[dq],78,256
+.Bd -literal -offset indent
+INCBIN \[dq]data.bin\[dq],78,256
+.Ed
 .Ss Unions
 Unions allow multiple memory allocations to share the same space in memory,
 like unions in C.
@@ -660,16 +737,19 @@ some important information.
 .Pp
 .Bd -literal -offset indent
 PRINTT \[dq]I'm the greatest programmer in the whole wide world\[rs]n\[dq]
-PRINTV (2+3)/5
+PRINTI (2 + 3) / 5
-PRINTF MUL(3.14,3987.0)
+PRINTV $FF00 + $F0
+PRINTF MUL(3.14, 3987.0)
 .Ed
 .Pp
 .Bl -inset
 .It Ic PRINTT
 prints out a string.
 .It Ic PRINTV
-prints out an integer value or, as in the example, the result of a calculation.
+prints out an integer value in hexadecimal or, as in the example, the result of
-Unsurprisingly, you can also print out a constant symbols value.
+a calculation. Unsurprisingly, you can also print out a constant symbols value.
+.It Ic PRINTI
+prints out a signed integer value.
 .It Ic PRINTF
 prints out a fixed point value.
 .El
@@ -740,7 +820,9 @@ You may nest
 .Ic INCLUDE
 calls infinitely (or until you run out of memory, whichever comes first).
 .Pp
-.Dl INCLUDE \[dq]irq.inc\[dq]
+.Bd -literal -offset indent
+    INCLUDE \[dq]irq.inc\[dq]
+.Ed
 .Pp
 .Ss Conditional assembling
 The four commands
@@ -816,7 +898,9 @@ The last one, Gameboy graphics, is quite interesting and useful.
 The values are actually pixel values and it converts the
 .Do chunky Dc data to Do planar Dc data as used in the Gameboy.
 .Pp
-.Dl DW \`01012323
+.Bd -literal -offset indent
+    DW \`01012323
+.Ed
 .Pp
 Admittedly, an expression with just a single number is quite boring.
 To spice things up a bit there are a few operators you can use to perform
@@ -957,6 +1041,34 @@ new string.
 the new string.
 .El
 .Pp
+.Ss Character maps
+.Pp
+When writing text that is meant to be displayed in the Game Boy, the ASCII
+characters used in the source code may not be the same ones used in the tileset
+used in the ROM.
+For example, the tiles used for uppercase letters may be placed starting at tile
+index 128, which makes it difficult to add text strings to the ROM.
+.Pp
+Character maps allow the code to map strings up to 16 characters long to an
+abitrary 8-bit value:
+.Pp
+.Bd -literal -offset indent
+CHARMAP "<LF>", 10
+CHARMAP "&iacute", 20
+CHARMAP "A", 128
+.Ed
+.Pp
+.Sy Note:
+Character maps affect all strings in the file from the point in which they are
+defined.
+This means that any string that the code may want to print as debug information
+will also be affected by it.
+.Pp
+.Sy Note:
+The output value of a mapping can be 0.
+If this happens, the assembler will treat this as the end of the string and the
+rest of it will be trimmed.
+.Pp
 .Ss Other functions
 There are a few other functions that do various useful things:
 .Pp
@@ -1039,6 +1151,7 @@ machine.
 .It Sx ATAN
 .It Sx ATAN2
 .It Sx BANK
+.It Sx CHARMAP
 .It Sx COS
 .It Sx DB
 .It Sx DEF
@@ -1068,6 +1181,7 @@ machine.
 .It Sx POPO
 .It Sx POPS
 .It Sx PRINTF
+.It Sx PRINTI
 .It Sx PRINTT
 .It Sx PRINTV
 .It Sx PURGE

src/asm/rpn.c

@@ -330,6 +330,15 @@ void rpn_SHL(struct Expression *expr, const struct Expression *src1,
 	     const struct Expression *src2)
 {
 	joinexpr();
+
+	if (src1->nVal < 0)
+		warning("Left shift of negative value: %d", src1->nVal);
+
+	if (src2->nVal < 0)
+		fatalerror("Shift by negative value: %d", src2->nVal);
+	else if (src2->nVal >= 32)
+		fatalerror("Shift by too big value: %d", src2->nVal);
+
 	expr->nVal = (expr->nVal << src2->nVal);
 	pushbyte(expr, RPN_SHL);
 }
@@ -338,6 +347,11 @@ void rpn_SHR(struct Expression *expr, const struct Expression *src1,
 	     const struct Expression *src2)
 {
 	joinexpr();
+	if (src2->nVal < 0)
+		fatalerror("Shift by negative value: %d", src2->nVal);
+	else if (src2->nVal >= 32)
+		fatalerror("Shift by too big value: %d", src2->nVal);
+
 	expr->nVal = (expr->nVal >> src2->nVal);
 	pushbyte(expr, RPN_SHR);
 }
@@ -355,7 +369,7 @@ void rpn_DIV(struct Expression *expr, const struct Expression *src1,
 {
 	joinexpr();
 	if (src2->nVal == 0)
-		fatalerror("division by zero");
+		fatalerror("Division by zero");
 
 	expr->nVal = (expr->nVal / src2->nVal);
 	pushbyte(expr, RPN_DIV);
@@ -366,7 +380,7 @@ void rpn_MOD(struct Expression *expr, const struct Expression *src1,
 {
 	joinexpr();
 	if (src2->nVal == 0)
-		fatalerror("division by zero");
+		fatalerror("Division by zero");
 
 	expr->nVal = (expr->nVal % src2->nVal);
 	pushbyte(expr, RPN_MOD);

src/asm/symbol.c

@@ -25,6 +25,7 @@
 
 #include "extern/err.h"
 
+#include "helpers.h"
 #include "version.h"
 
 struct sSymbol *tHashedSymbols[HASHSIZE];
@@ -40,7 +41,7 @@ static char SavedTIMESTAMP_ISO8601_LOCAL[256];
 static char SavedTIMESTAMP_ISO8601_UTC[256];
 static char SavedDAY[3];
 static char SavedMONTH[3];
-static char SavedYEAR[5];
+static char SavedYEAR[20];
 static char SavedHOUR[3];
 static char SavedMINUTE[3];
 static char SavedSECOND[3];
@@ -62,7 +63,7 @@ void helper_RemoveLeadingZeros(char *string)
 	memmove(string, new_beginning, strlen(new_beginning) + 1);
 }
 
-int32_t Callback_NARG(struct sSymbol *sym)
+int32_t Callback_NARG(unused_ struct sSymbol *sym)
 {
 	uint32_t i = 0;
 
@@ -72,7 +73,7 @@ int32_t Callback_NARG(struct sSymbol *sym)
 	return i;
 }
 
-int32_t Callback__LINE__(struct sSymbol __attribute__((unused)) *sym)
+int32_t Callback__LINE__(unused_ struct sSymbol *sym)
 {
 	return nLineNo;
 }
@@ -122,7 +123,9 @@ struct sSymbol *createsymbol(char *s)
 		return NULL;
 	}
 
-	strcpy((*ppsym)->tzName, s);
+	if (snprintf((*ppsym)->tzName, MAXSYMLEN + 1, "%s", s) > MAXSYMLEN)
+		warning("Symbol name is too long: '%s'", s);
+
 	(*ppsym)->nValue = 0;
 	(*ppsym)->nType = 0;
 	(*ppsym)->pScope = NULL;
@@ -130,7 +133,13 @@ struct sSymbol *createsymbol(char *s)
 	(*ppsym)->pMacro = NULL;
 	(*ppsym)->pSection = NULL;
 	(*ppsym)->Callback = NULL;
-	strcpy((*ppsym)->tzFileName, tzCurrentFileName);
+
+	if (snprintf((*ppsym)->tzFileName, _MAX_PATH + 1, "%s",
+		     tzCurrentFileName) > _MAX_PATH) {
+		fatalerror("%s: File name is too long: '%s'", __func__,
+			   tzCurrentFileName);
+	}
+
 	(*ppsym)->nFileLine = fstk_GetLine();
 	return *ppsym;
 }
@@ -509,7 +518,7 @@ void sym_SetMacroArgID(uint32_t nMacroCount)
 {
 	char s[256];
 
-	sprintf(s, "_%u", nMacroCount);
+	snprintf(s, sizeof(s), "_%u", nMacroCount);
 	newmacroargs[MAXMACROARGS] = strdup(s);
 }
 
@@ -560,7 +569,7 @@ void sym_AddEqu(char *tzSym, int32_t value)
  *
  * If the desired symbol is a string it needs to be passed to this function with
  * quotes inside the string, like sym_AddString("name", "\"test\"), or the
- * assembler won't be able to use it with DB and similar. This is equivalent as
+ * assembler won't be able to use it with DB and similar. This is equivalent to
  * ``` name EQUS "\"test\"" ```
  *
  * If the desired symbol is a register or a number, just the terminator quotes
@@ -665,7 +674,7 @@ void sym_AddReloc(char *tzSym)
 
 			struct sSymbol *parent = pScope->pScope ?
 						 pScope->pScope : pScope;
-			int32_t parentLen = localPtr - tzSym;
+			uint32_t parentLen = localPtr - tzSym;
 
 			if (strchr(localPtr + 1, '.') != NULL) {
 				fatalerror("'%s' is a nonsensical reference to a nested local symbol",
@@ -965,16 +974,22 @@ void sym_Init(void)
 		 * The '?' have to be escaped or they will be treated as
 		 * trigraphs...
 		 */
-		strcpy(SavedTIME, "\"\?\?:\?\?:\?\?\"");
+		snprintf(SavedTIME, sizeof(SavedTIME),
-		strcpy(SavedDATE, "\"\?\? \?\?\? \?\?\?\?\"");
+			 "\"\?\?:\?\?:\?\?\"");
-		strcpy(SavedTIMESTAMP_ISO8601_LOCAL, "\"\?\?\?\?-\?\?-\?\?T\?\?:\?\?:\?\?+\?\?\?\?\"");
+		snprintf(SavedDATE, sizeof(SavedDATE),
-		strcpy(SavedTIMESTAMP_ISO8601_UTC, "\"\?\?\?\?-\?\?-\?\?T\?\?:\?\?:\?\?Z\"");
+			 "\"\?\? \?\?\? \?\?\?\?\"");
-		strcpy(SavedDAY, "1");
+		snprintf(SavedTIMESTAMP_ISO8601_LOCAL,
-		strcpy(SavedMONTH, "1");
+			 sizeof(SavedTIMESTAMP_ISO8601_LOCAL),
-		strcpy(SavedYEAR, "1900");
+			 "\"\?\?\?\?-\?\?-\?\?T\?\?:\?\?:\?\?+\?\?\?\?\"");
-		strcpy(SavedHOUR, "0");
+		snprintf(SavedTIMESTAMP_ISO8601_UTC,
-		strcpy(SavedMINUTE, "0");
+			 sizeof(SavedTIMESTAMP_ISO8601_UTC),
-		strcpy(SavedSECOND, "0");
+			 "\"\?\?\?\?-\?\?-\?\?T\?\?:\?\?:\?\?Z\"");
+		snprintf(SavedDAY, sizeof(SavedDAY), "1");
+		snprintf(SavedMONTH, sizeof(SavedMONTH), "1");
+		snprintf(SavedYEAR, sizeof(SavedYEAR), "1900");
+		snprintf(SavedHOUR, sizeof(SavedHOUR), "0");
+		snprintf(SavedMINUTE, sizeof(SavedMINUTE), "0");
+		snprintf(SavedSECOND, sizeof(SavedSECOND), "0");
 	}
 
 	sym_AddString("__TIME__", SavedTIME);

src/extern/err.c

@@ -33,7 +33,7 @@ void rgbds_vwarnx(const char *fmt, va_list ap)
 	putc('\n', stderr);
 }
 
-noreturn void rgbds_verr(int status, const char *fmt, va_list ap)
+noreturn_ void rgbds_verr(int status, const char *fmt, va_list ap)
 {
 	fprintf(stderr, "error");
 	if (fmt) {
@@ -44,7 +44,7 @@ noreturn void rgbds_verr(int status, const char *fmt, va_list ap)
 	exit(status);
 }
 
-noreturn void rgbds_verrx(int status, const char *fmt, va_list ap)
+noreturn_ void rgbds_verrx(int status, const char *fmt, va_list ap)
 {
 	fprintf(stderr, "error");
 	if (fmt) {
@@ -73,7 +73,7 @@ void rgbds_warnx(const char *fmt, ...)
 	va_end(ap);
 }
 
-noreturn void rgbds_err(int status, const char *fmt, ...)
+noreturn_ void rgbds_err(int status, const char *fmt, ...)
 {
 	va_list ap;
 
@@ -82,7 +82,7 @@ noreturn void rgbds_err(int status, const char *fmt, ...)
 	va_end(ap);
 }
 
-noreturn void rgbds_errx(int status, const char *fmt, ...)
+noreturn_ void rgbds_errx(int status, const char *fmt, ...)
 {
 	va_list ap;
 

src/fix/main.c

@@ -20,9 +20,9 @@
 static void print_usage(void)
 {
 	printf(
-"usage: rgbfix [-CcjsVv] [-i game_id] [-k licensee_str] [-l licensee_id]\n"
+"usage: rgbfix [-CcjsVv] [-f fix_spec] [-i game_id] [-k licensee_str]\n"
-"              [-m mbc_type] [-n rom_version] [-p pad_value] [-r ram_size]\n"
+"              [-l licensee_id] [-m mbc_type] [-n rom_version] [-p pad_value]\n"
-"              [-t title_str] file\n");
+"              [-r ram_size] [-t title_str] file\n");
 	exit(1);
 }
 
@@ -37,7 +37,12 @@ int main(int argc, char *argv[])
 	 */
 
 	/* all flags default to false unless options specify otherwise */
-	bool validate = false;
+	bool fixlogo = false;
+	bool fixheadsum = false;
+	bool fixglobalsum = false;
+	bool trashlogo = false;
+	bool trashheadsum = false;
+	bool trashglobalsum = false;
 	bool settitle = false;
 	bool setid = false;
 	bool colorcompatible = false;
@@ -61,7 +66,7 @@ int main(int argc, char *argv[])
 	int version = 0;   /* mask ROM version number */
 	int padvalue = 0;  /* to pad the rom with if it changes size */
 
-	while ((ch = getopt(argc, argv, "Cci:jk:l:m:n:p:sr:t:Vv")) != -1) {
+	while ((ch = getopt(argc, argv, "Ccf:i:jk:l:m:n:p:sr:t:Vv")) != -1) {
 		switch (ch) {
 		case 'C':
 			coloronly = true;
@@ -69,6 +74,14 @@ int main(int argc, char *argv[])
 		case 'c':
 			colorcompatible = true;
 			break;
+		case 'f':
+			fixlogo = strchr(optarg, 'l');
+			fixheadsum = strchr(optarg, 'h');
+			fixglobalsum = strchr(optarg, 'g');
+			trashlogo = strchr(optarg, 'L');
+			trashheadsum = strchr(optarg, 'H');
+			trashglobalsum = strchr(optarg, 'G');
+			break;
 		case 'i':
 			setid = true;
 
@@ -168,7 +181,9 @@ int main(int argc, char *argv[])
 			printf("rgbfix %s\n", get_package_version_string());
 			exit(0);
 		case 'v':
-			validate = true;
+			fixlogo = true;
+			fixheadsum = true;
+			fixglobalsum = true;
 			break;
 		default:
 			print_usage();
@@ -192,10 +207,20 @@ int main(int argc, char *argv[])
 		err(1, "Error opening file %s", argv[argc - 1]);
 
 	/*
-	 * Write changes to ROM
+	 * Read ROM header
+	 *
+	 * Offsets in the buffer are 0x100 less than the equivalent in ROM.
 	 */
 
-	if (validate) {
+	uint8_t header[0x50];
+
+	if (fseek(rom, 0x100, SEEK_SET) != 0)
+		err(1, "Could not locate ROM header");
+	if (fread(header, sizeof(uint8_t), sizeof(header), rom)
+	    != sizeof(header))
+		err(1, "Could not read ROM header");
+
+	if (fixlogo || trashlogo) {
 		/*
 		 * Offset 0x104–0x133: Nintendo Logo
 		 * This is a bitmap image that displays when the Game Boy is
@@ -205,7 +230,7 @@ int main(int argc, char *argv[])
 		/*
 		 * See also: global checksums at 0x14D–0x14F, They must
 		 * also be correct for the game to boot, so we fix them
-		 * as well when the -v flag is set.
+		 * as well when requested with the -f flag.
 		 */
 
 		uint8_t ninlogo[48] = {
@@ -217,8 +242,12 @@ int main(int argc, char *argv[])
 			0xDD, 0xDC, 0x99, 0x9F, 0xBB, 0xB9, 0x33, 0x3E
 		};
 
-		fseek(rom, 0x104, SEEK_SET);
+		if (trashlogo) {
-		fwrite(ninlogo, 1, 48, rom);
+			for (int i = 0; i < sizeof(ninlogo); i++)
+				ninlogo[i] = ~ninlogo[i];
+		}
+
+		memcpy(header + 0x04, ninlogo, sizeof(ninlogo));
 	}
 
 	if (settitle) {
@@ -239,11 +268,10 @@ int main(int argc, char *argv[])
 		 * characters may conflict with the title.
 		 */
 
-		fseek(rom, 0x134, SEEK_SET);
+		int n = snprintf((char *)header + 0x34, 16, "%s", title);
-		fwrite(title, 1, strlen(title) + 1, rom);
 
-		while (ftell(rom) < 0x143)
+		for (int i = 16; i > n; i--)
-			fputc(0, rom);
+			header[0x34 + i] = '\0';
 	}
 
 	if (setid) {
@@ -253,8 +281,7 @@ int main(int argc, char *argv[])
 		 * characters).
 		 */
 
-		fseek(rom, 0x13F, SEEK_SET);
+		memcpy(header + 0x3F, id, 4);
-		fwrite(id, 1, 4, rom);
 	}
 
 	if (colorcompatible) {
@@ -272,20 +299,12 @@ int main(int argc, char *argv[])
 		 * may conflict.
 		 */
 
-		uint8_t byte;
+		header[0x43] |= 1 << 7;
-
-		fseek(rom, 0x143, SEEK_SET);
-		byte = fgetc(rom);
-
-		byte |= 1 << 7;
 		if (coloronly)
-			byte |= 1 << 6;
+			header[0x43] |= 1 << 6;
 
-		if (byte & 0x3F)
+		if (header[0x43] & 0x3F)
 			warnx("Color flag conflicts with game title");
-
-		fseek(rom, 0x143, SEEK_SET);
-		fputc(byte, rom);
 	}
 
 	if (setnewlicensee) {
@@ -301,8 +320,8 @@ int main(int argc, char *argv[])
 		 * as a Super Game Boy flag.
 		 */
 
-		fseek(rom, 0x144, SEEK_SET);
+		header[0x44] = newlicensee[0];
-		fwrite(newlicensee, 1, 2, rom);
+		header[0x45] = newlicensee[1];
 	}
 
 	if (super) {
@@ -321,8 +340,7 @@ int main(int argc, char *argv[])
 		if (!setlicensee)
 			warnx("You should probably set both '-s' and '-l 0x33'");
 
-		fseek(rom, 0x146, SEEK_SET);
+		header[0x46] = 3;
-		fputc(3, rom);
 	}
 
 	if (setcartridge) {
@@ -332,8 +350,7 @@ int main(int argc, char *argv[])
 		 * external RAM, timer, rumble, or battery.
 		 */
 
-		fseek(rom, 0x147, SEEK_SET);
+		header[0x47] = cartridge;
-		fputc(cartridge, rom);
 	}
 
 	if (resize) {
@@ -347,8 +364,13 @@ int main(int argc, char *argv[])
 		int headbyte;
 		uint8_t *buf;
 
-		fseek(rom, 0, SEEK_END);
+		if (fseek(rom, 0, SEEK_END) != 0)
+			err(1, "Could not pad ROM file");
+
 		romsize = ftell(rom);
+		if (romsize == -1)
+			err(1, "Could not pad ROM file");
+
 		newsize = 0x8000;
 
 		headbyte = 0;
@@ -361,11 +383,14 @@ int main(int argc, char *argv[])
 			warnx("ROM size is bigger than 8MiB");
 
 		buf = malloc(newsize - romsize);
-		memset(buf, padvalue, newsize - romsize);
+		if (buf == NULL)
-		fwrite(buf, 1, newsize - romsize, rom);
+			errx(1, "Couldn't allocate memory for padded ROM.");
 
-		fseek(rom, 0x148, SEEK_SET);
+		memset(buf, padvalue, newsize - romsize);
-		fputc(headbyte, rom);
+		if (fwrite(buf, 1, newsize - romsize, rom) != newsize - romsize)
+			err(1, "Could not pad ROM file");
+
+		header[0x48] = headbyte;
 
 		free(buf);
 	}
@@ -375,8 +400,7 @@ int main(int argc, char *argv[])
 		 * Offset 0x149: RAM Size
 		 */
 
-		fseek(rom, 0x149, SEEK_SET);
+		header[0x49] = ramsize;
-		fputc(ramsize, rom);
 	}
 
 	if (nonjapan) {
@@ -384,8 +408,7 @@ int main(int argc, char *argv[])
 		 * Offset 0x14A: Non-Japanese Region Flag
 		 */
 
-		fseek(rom, 0x14A, SEEK_SET);
+		header[0x4A] = 1;
-		fputc(1, rom);
 	}
 
 	if (setlicensee) {
@@ -401,8 +424,7 @@ int main(int argc, char *argv[])
 		 * See also: the New Licensee ID at 0x144–0x145.
 		 */
 
-		fseek(rom, 0x14B, SEEK_SET);
+		header[0x4B] = licensee;
-		fputc(licensee, rom);
 	}
 
 	if (setversion) {
@@ -411,46 +433,71 @@ int main(int argc, char *argv[])
 		 * Which version of the ROM this is.
 		 */
 
-		fseek(rom, 0x14C, SEEK_SET);
+		header[0x4C] = version;
-		fputc(version, rom);
 	}
 
-	if (validate) {
+	if (fixheadsum || trashheadsum) {
 		/*
 		 * Offset 0x14D: Header Checksum
 		 */
 
 		uint8_t headcksum = 0;
 
-		fseek(rom, 0x134, SEEK_SET);
+		for (int i = 0x34; i < 0x4D; ++i)
-		for (int i = 0; i < (0x14D - 0x134); ++i)
+			headcksum = headcksum - header[i] - 1;
-			headcksum = headcksum - fgetc(rom) - 1;
 
-		fseek(rom, 0x14D, SEEK_SET);
+		if (trashheadsum)
-		fputc(headcksum, rom);
+			headcksum = ~headcksum;
 
+		header[0x4D] = headcksum;
+	}
+
+	/*
+	 * Before calculating the global checksum, we must write the modified
+	 * header to the ROM.
+	 */
+
+	if (fseek(rom, 0x100, SEEK_SET) != 0)
+		err(1, "Could not locate header for writing");
+
+	if (fwrite(header, sizeof(uint8_t), sizeof(header), rom)
+	    != sizeof(header))
+		err(1, "Could not write modified ROM header");
+
+	if (fixglobalsum || trashglobalsum) {
 		/*
 		 * Offset 0x14E–0x14F: Global Checksum
 		 */
 
 		uint16_t globalcksum = 0;
 
-		rewind(rom);
+		if (fseek(rom, 0, SEEK_SET) != 0)
-		for (int i = 0; i < 0x14E; ++i)
+			err(1, "Could not start calculating global checksum");
-			globalcksum += fgetc(rom);
 
+		int i = 0;
 		int byte;
 
-		fseek(rom, 0x150, SEEK_SET);
+		while ((byte = fgetc(rom)) != EOF) {
-		while ((byte = fgetc(rom)) != EOF)
+			i++;
-			globalcksum += byte;
+			if (i != 0x150)
+				globalcksum += byte;
+		}
+
+		if (ferror(rom))
+			err(1, "Could not calculate global checksum");
+
+		if (trashglobalsum)
+			globalcksum = ~globalcksum;
 
 		fseek(rom, 0x14E, SEEK_SET);
 		fputc(globalcksum >> 8, rom);
 		fputc(globalcksum & 0xFF, rom);
+		if (ferror(rom))
+			err(1, "Could not write global checksum");
 	}
 
-	fclose(rom);
+	if (fclose(rom) != 0)
+		err(1, "Could not complete ROM write");
 
 	return 0;
 }

src/fix/rgbfix.1

@@ -5,7 +5,7 @@
 .\"
 .\" SPDX-License-Identifier: MIT
 .\"
-.Dd January 26, 2018
+.Dd March 11, 2018
 .Dt RGBFIX 1
 .Os RGBDS Manual
 .Sh NAME
@@ -14,6 +14,7 @@
 .Sh SYNOPSIS
 .Nm rgbfix
 .Op Fl CcjsVv
+.Op Fl f Ar fix_spec
 .Op Fl i Ar game_id
 .Op Fl k Ar licensee_str
 .Op Fl l Ar licensee_id
@@ -46,6 +47,30 @@ If both this and the
 flag are set,
 .Fl C
 takes precedence.
+.It Fl f Ar fix_spec
+Fix certain header values that the Game Boy checks for correctness.
+Alternatively, intentionally trash these values by writing their binary inverse
+instead.
+.Ar fix_spec
+is a string containing any combination of the following characters:
+.Pp
+.Bl -tag -compact -width xx
+.It Cm l
+Fix the Nintendo logo
+.Pq Ad 0x104 Ns \(en Ns Ad 0x133 .
+.It Cm L
+Trash the Nintendo logo.
+.It Cm h
+Fix the header checksum
+.Pq Ad 0x14D .
+.It Cm H
+Trash the header checksum.
+.It Cm g
+Fix the global checksum
+.Pq Ad 0x14E Ns \(en Ns Ad 0x14F .
+.It Cm G
+Trash the global checksum.
+.El
 .It Fl i Ar game_id
 Set the game ID string
 .Pq Ad 0x13F Ns \(en Ns Ad 0x142
@@ -104,12 +129,8 @@ overlapping portion of the title.
 .It Fl V
 Print the version of the program and exit.
 .It Fl v
-Validate the header and fix checksums: the Nintendo character area
+Equivalent to
-.Pq Ad 0x104 Ns \(en Ns Ad 0x133 ,
+.Fl f Cm lhg .
-the header checksum
-.Pq Ad 0x14D ,
-and the global checksum
-.Pq Ad 0x14E Ns \(en Ns Ad 0x14F .
 .El
 .Sh EXAMPLES
 Most values in the ROM header are only cosmetic.

src/gbz80.7

@@ -5,7 +5,7 @@
 .\"
 .\" SPDX-License-Identifier: MIT
 .\"
-.Dd January 26, 2018
+.Dd February 23, 2018
 .Dt GBZ80 7
 .Os RGBDS Manual
 .Sh NAME
@@ -24,8 +24,10 @@ as destination can omit the destination as it is assumed it's register
 .Sy A .
 The following two lines have the same effect:
 .Pp
-.Dl OR A,B
+.Bd -literal -offset indent
-.Dl OR B
+OR A,B
+OR B
+.Ed
 .Pp
 .Sh LEGEND
 List of abbreviations used in this document.

src/gfx/gb.c

@@ -6,6 +6,7 @@
  * SPDX-License-Identifier: MIT
  */
 
+#include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
 
@@ -31,23 +32,18 @@ void transpose_tiles(struct GBImage *gb, int width)
 	gb->data = newdata;
 }
 
-void png_to_gb(const struct PNGImage png, struct GBImage *gb)
+void raw_to_gb(const struct RawIndexedImage *raw_image, struct GBImage *gb)
 {
 	int x, y, byte;
-	png_byte index;
+	uint8_t index;
 
-	for (y = 0; y < png.height; y++) {
+	for (y = 0; y < raw_image->height; y++) {
-		for (x = 0; x < png.width; x++) {
+		for (x = 0; x < raw_image->width; x++) {
-			index = png.data[y][x];
+			index = raw_image->data[y][x];
 			index &= (1 << depth) - 1;
 
-			if (!gb->horizontal) {
+			byte = y * depth
-				byte = y * depth
+				+ x / 8 * raw_image->height / 8 * 8 * depth;
-				     + x / 8 * png.height / 8 * 8 * depth;
-			} else {
-				byte = y * depth
-				     + x / 8 * png.height / 8 * 8 * depth;
-			}
 			gb->data[byte] |= (index & 1) << (7 - x % 8);
 			if (depth == 2) {
 				gb->data[byte + 1] |=
@@ -57,18 +53,18 @@ void png_to_gb(const struct PNGImage png, struct GBImage *gb)
 	}
 
 	if (!gb->horizontal)
-		transpose_tiles(gb, png.width / 8);
+		transpose_tiles(gb, raw_image->width / 8);
 }
 
-void output_file(const struct Options opts, const struct GBImage gb)
+void output_file(const struct Options *opts, const struct GBImage *gb)
 {
 	FILE *f;
 
-	f = fopen(opts.outfile, "wb");
+	f = fopen(opts->outfile, "wb");
 	if (!f)
-		err(1, "Opening output file '%s' failed", opts.outfile);
+		err(1, "Opening output file '%s' failed", opts->outfile);
 
-	fwrite(gb.data, 1, gb.size - gb.trim * 8 * depth, f);
+	fwrite(gb->data, 1, gb->size - gb->trim * 8 * depth, f);
 
 	fclose(f);
 }
@@ -89,7 +85,7 @@ int get_tile_index(uint8_t *tile, uint8_t **tiles, int num_tiles, int tile_size)
 	return -1;
 }
 
-void create_tilemap(const struct Options opts, struct GBImage *gb,
+void create_tilemap(const struct Options *opts, struct GBImage *gb,
 		    struct Tilemap *tilemap)
 {
 	int i, j;
@@ -105,10 +101,15 @@ void create_tilemap(const struct Options opts, struct GBImage *gb,
 	tile_size = sizeof(uint8_t) * depth * 8;
 	gb_size = gb->size - (gb->trim * tile_size);
 	max_tiles = gb_size / tile_size;
-	tiles = malloc(sizeof(uint8_t *) * max_tiles);
+
+	/* If the input image doesn't fill the last tile, increase the count. */
+	if (gb_size > max_tiles * tile_size)
+		max_tiles++;
+
+	tiles = calloc(max_tiles, sizeof(uint8_t *));
 	num_tiles = 0;
 
-	tilemap->data = malloc(sizeof(uint8_t) * max_tiles);
+	tilemap->data = calloc(max_tiles, sizeof(uint8_t));
 	tilemap->size = 0;
 
 	gb_i = 0;
@@ -118,7 +119,7 @@ void create_tilemap(const struct Options opts, struct GBImage *gb,
 			tile[i] = gb->data[gb_i];
 			gb_i++;
 		}
-		if (opts.unique) {
+		if (opts->unique) {
 			index = get_tile_index(tile, tiles, num_tiles,
 					       tile_size);
 			if (index < 0) {
@@ -135,7 +136,7 @@ void create_tilemap(const struct Options opts, struct GBImage *gb,
 		tilemap->size++;
 	}
 
-	if (opts.unique) {
+	if (opts->unique) {
 		free(gb->data);
 		gb->data = malloc(tile_size * num_tiles);
 		for (i = 0; i < num_tiles; i++) {
@@ -152,43 +153,44 @@ void create_tilemap(const struct Options opts, struct GBImage *gb,
 	free(tiles);
 }
 
-void output_tilemap_file(const struct Options opts,
+void output_tilemap_file(const struct Options *opts,
-			 const struct Tilemap tilemap)
+			 const struct Tilemap *tilemap)
 {
 	FILE *f;
 
-	f = fopen(opts.mapfile, "wb");
+	f = fopen(opts->mapfile, "wb");
 	if (!f)
-		err(1, "Opening tilemap file '%s' failed", opts.mapfile);
+		err(1, "Opening tilemap file '%s' failed", opts->mapfile);
 
-	fwrite(tilemap.data, 1, tilemap.size, f);
+	fwrite(tilemap->data, 1, tilemap->size, f);
 	fclose(f);
 
-	if (opts.mapout)
+	if (opts->mapout)
-		free(opts.mapfile);
+		free(opts->mapfile);
 }
 
-void output_palette_file(const struct Options opts, const struct PNGImage png)
+void output_palette_file(const struct Options *opts,
+			 const struct RawIndexedImage *raw_image)
 {
 	FILE *f;
-	int i, colors, color;
+	int i, color;
-	png_color *palette;
+	uint8_t cur_bytes[2];
 
-	if (png_get_PLTE(png.png, png.info, &palette, &colors)) {
+	f = fopen(opts->palfile, "wb");
-		f = fopen(opts.palfile, "wb");
+	if (!f)
-		if (!f) {
+		err(1, "Opening palette file '%s' failed", opts->palfile);
-			err(1, "Opening palette file '%s' failed",
+
-			    opts.palfile);
+	for (i = 0; i < raw_image->num_colors; i++) {
-		}
+		color =
-		for (i = 0; i < colors; i++) {
+			raw_image->palette[i].blue  >> 3 << 10 |
-			color = palette[i].blue >> 3 << 10
+			raw_image->palette[i].green >> 3 <<  5 |
-			      | palette[i].green >> 3 << 5
+			raw_image->palette[i].red   >> 3;
-			      | palette[i].red >> 3;
+		cur_bytes[0] = color & 0xFF;
-			fwrite(&color, 2, 1, f);
+		cur_bytes[1] = color >> 8;
-		}
+		fwrite(cur_bytes, 2, 1, f);
-		fclose(f);
 	}
+	fclose(f);
 
-	if (opts.palout)
+	if (opts->palout)
-		free(opts.palfile);
+		free(opts->palfile);
 }

src/gfx/main.c

@@ -6,6 +6,7 @@
  * SPDX-License-Identifier: MIT
  */
 
+#include <png.h>
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
@@ -26,7 +27,8 @@ int main(int argc, char *argv[])
 {
 	int ch, size;
 	struct Options opts = {0};
-	struct PNGImage png = {0};
+	struct ImageOptions png_options = {0};
+	struct RawIndexedImage *raw_image;
 	struct GBImage gb = {0};
 	struct Tilemap tilemap = {0};
 	char *ext;
@@ -51,6 +53,7 @@ int main(int argc, char *argv[])
 			break;
 		case 'F':
 			opts.hardfix = true;
+			/* fallthrough */
 		case 'f':
 			opts.fix = true;
 			break;
@@ -102,80 +105,89 @@ int main(int argc, char *argv[])
 
 	colors = 1 << depth;
 
-	input_png_file(opts, &png);
+	raw_image = input_png_file(&opts, &png_options);
 
-	png.mapfile = "";
+	png_options.mapfile = "";
-	png.palfile = "";
+	png_options.palfile = "";
 
-	get_text(&png);
+	if (png_options.horizontal != opts.horizontal) {
-
-	if (png.horizontal != opts.horizontal) {
 		if (opts.verbose)
 			warnx(errmsg, "horizontal");
 
 		if (opts.hardfix)
-			png.horizontal = opts.horizontal;
+			png_options.horizontal = opts.horizontal;
 	}
 
-	if (png.horizontal)
+	if (png_options.horizontal)
-		opts.horizontal = png.horizontal;
+		opts.horizontal = png_options.horizontal;
 
-	if (png.trim != opts.trim) {
+	if (png_options.trim != opts.trim) {
 		if (opts.verbose)
 			warnx(errmsg, "trim");
 
 		if (opts.hardfix)
-			png.trim = opts.trim;
+			png_options.trim = opts.trim;
 	}
 
-	if (png.trim)
+	if (png_options.trim)
-		opts.trim = png.trim;
+		opts.trim = png_options.trim;
 
-	if (opts.trim > png.width / 8 - 1) {
+	if (raw_image->width % 8) {
-		errx(1, "Trim (%i) for input png file '%s' too large (max: %i)",
+		errx(1, "Input PNG file %s not sized correctly. The image's width must be a multiple of 8.",
-		     opts.trim, opts.infile, png.width / 8 - 1);
+		     opts.infile);
+	}
+	if (raw_image->width / 8 > 1 && raw_image->height % 8) {
+		errx(1, "Input PNG file %s not sized correctly. If the image is more than 1 tile wide, its height must be a multiple of 8.",
+		     opts.infile);
 	}
 
-	if (strcmp(png.mapfile, opts.mapfile) != 0) {
+	if (opts.trim &&
+	    opts.trim > (raw_image->width / 8) * (raw_image->height / 8) - 1) {
+		errx(1, "Trim (%i) for input raw_image file '%s' too large (max: %i)",
+		     opts.trim, opts.infile,
+		     (raw_image->width / 8) * (raw_image->height / 8) - 1);
+	}
+
+	if (strcmp(png_options.mapfile, opts.mapfile) != 0) {
 		if (opts.verbose)
 			warnx(errmsg, "tilemap file");
 
 		if (opts.hardfix)
-			png.mapfile = opts.mapfile;
+			png_options.mapfile = opts.mapfile;
 	}
 	if (!*opts.mapfile)
-		opts.mapfile = png.mapfile;
+		opts.mapfile = png_options.mapfile;
 
-	if (png.mapout != opts.mapout) {
+	if (png_options.mapout != opts.mapout) {
 		if (opts.verbose)
 			warnx(errmsg, "tilemap file");
 
 		if (opts.hardfix)
-			png.mapout = opts.mapout;
+			png_options.mapout = opts.mapout;
 	}
-	if (png.mapout)
+	if (png_options.mapout)
-		opts.mapout = png.mapout;
+		opts.mapout = png_options.mapout;
 
-	if (strcmp(png.palfile, opts.palfile) != 0) {
+	if (strcmp(png_options.palfile, opts.palfile) != 0) {
 		if (opts.verbose)
 			warnx(errmsg, "palette file");
 
 		if (opts.hardfix)
-			png.palfile = opts.palfile;
+			png_options.palfile = opts.palfile;
 	}
 	if (!*opts.palfile)
-		opts.palfile = png.palfile;
+		opts.palfile = png_options.palfile;
 
-	if (png.palout != opts.palout) {
+	if (png_options.palout != opts.palout) {
 		if (opts.verbose)
 			warnx(errmsg, "palette file");
 
 		if (opts.hardfix)
-			png.palout = opts.palout;
+			png_options.palout = opts.palout;
 	}
 
-	if (png.palout)
+	if (png_options.palout)
-		opts.palout = png.palout;
+		opts.palout = png_options.palout;
 
 	if (!*opts.mapfile && opts.mapout) {
 		ext = strrchr(opts.infile, '.');
@@ -209,31 +221,29 @@ int main(int argc, char *argv[])
 		}
 	}
 
-	gb.size = png.width * png.height * depth / 8;
+	gb.size = raw_image->width * raw_image->height * depth / 8;
 	gb.data = calloc(gb.size, 1);
 	gb.trim = opts.trim;
 	gb.horizontal = opts.horizontal;
 
 	if (*opts.outfile || *opts.mapfile) {
-		png_to_gb(png, &gb);
+		raw_to_gb(raw_image, &gb);
-		create_tilemap(opts, &gb, &tilemap);
+		create_tilemap(&opts, &gb, &tilemap);
 	}
 
 	if (*opts.outfile)
-		output_file(opts, gb);
+		output_file(&opts, &gb);
 
 	if (*opts.mapfile)
-		output_tilemap_file(opts, tilemap);
+		output_tilemap_file(&opts, &tilemap);
 
 	if (*opts.palfile)
-		output_palette_file(opts, png);
+		output_palette_file(&opts, raw_image);
 
-	if (opts.fix || opts.debug) {
+	if (opts.fix || opts.debug)
-		set_text(&png);
+		output_png_file(&opts, &png_options, raw_image);
-		output_png_file(opts, &png);
-	}
 
-	free_png_data(&png);
+	destroy_raw_image(&raw_image);
 	free(gb.data);
 
 	return 0;

src/gfx/makepng.c

@@ -6,25 +6,150 @@
  * SPDX-License-Identifier: MIT
  */
 
+#include <png.h>
+#include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 
 #include "gfx/main.h"
 
-void input_png_file(const struct Options opts, struct PNGImage *img)
+static void initialize_png(struct PNGImage *img, FILE *f);
+static struct RawIndexedImage *indexed_png_to_raw(struct PNGImage *img);
+static struct RawIndexedImage *grayscale_png_to_raw(struct PNGImage *img);
+static struct RawIndexedImage *truecolor_png_to_raw(struct PNGImage *img);
+static void get_text(const struct PNGImage *img,
+		     struct ImageOptions *png_options);
+static void set_text(const struct PNGImage *img,
+		     const struct ImageOptions *png_options);
+static void free_png_data(const struct PNGImage *png);
+
+struct RawIndexedImage *input_png_file(const struct Options *opts,
+				       struct ImageOptions *png_options)
+{
+	struct PNGImage img;
+	struct RawIndexedImage *raw_image;
+	FILE *f;
+
+	f = fopen(opts->infile, "rb");
+	if (!f)
+		err(1, "Opening input png file '%s' failed", opts->infile);
+
+	initialize_png(&img, f);
+
+	if (img.depth != depth) {
+		if (opts->verbose) {
+			warnx("Image bit depth is not %i (is %i).",
+			      depth, img.depth);
+		}
+	}
+
+	switch (img.type) {
+	case PNG_COLOR_TYPE_PALETTE:
+		raw_image = indexed_png_to_raw(&img); break;
+	case PNG_COLOR_TYPE_GRAY:
+	case PNG_COLOR_TYPE_GRAY_ALPHA:
+		raw_image = grayscale_png_to_raw(&img); break;
+	case PNG_COLOR_TYPE_RGB:
+	case PNG_COLOR_TYPE_RGB_ALPHA:
+		raw_image = truecolor_png_to_raw(&img); break;
+	default:
+		/* Shouldn't happen, but might as well handle just in case. */
+		errx(1, "Input PNG file is of invalid color type.");
+	}
+
+	get_text(&img, png_options);
+
+	png_destroy_read_struct(&img.png, &img.info, NULL);
+	fclose(f);
+	free_png_data(&img);
+
+	return raw_image;
+}
+
+void output_png_file(const struct Options *opts,
+		     const struct ImageOptions *png_options,
+		     const struct RawIndexedImage *raw_image)
 {
 	FILE *f;
-	int i, y, num_trans;
+	char *outfile;
-	bool has_palette = false;
+	struct PNGImage img;
-	png_byte *trans_alpha;
+	png_color *png_palette;
-	png_color_16 *trans_values;
+	int i;
-	bool *full_alpha;
-	png_color *palette;
 
-	f = fopen(opts.infile, "rb");
+	/*
+	 * TODO: Variable outfile is for debugging purposes. Eventually,
+	 * opts.infile will be used directly.
+	 */
+	if (opts->debug) {
+		outfile = malloc(strlen(opts->infile) + 5);
+		strcpy(outfile, opts->infile);
+		strcat(outfile, ".out");
+	} else {
+		outfile = opts->infile;
+	}
+
+	f = fopen(outfile, "wb");
 	if (!f)
-		err(1, "Opening input png file '%s' failed", opts.infile);
+		err(1, "Opening output png file '%s' failed", outfile);
 
+	img.png = png_create_write_struct(PNG_LIBPNG_VER_STRING,
+					  NULL, NULL, NULL);
+	if (!img.png)
+		errx(1, "Creating png structure failed");
+
+	img.info = png_create_info_struct(img.png);
+	if (!img.info)
+		errx(1, "Creating png info structure failed");
+
+	if (setjmp(png_jmpbuf(img.png)))
+		exit(1);
+
+	png_init_io(img.png, f);
+
+	png_set_IHDR(img.png, img.info, raw_image->width, raw_image->height,
+		     8, PNG_COLOR_TYPE_PALETTE, PNG_INTERLACE_NONE,
+		     PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);
+
+	png_palette = malloc(sizeof(png_color *) * raw_image->num_colors);
+	for (i = 0; i < raw_image->num_colors; i++) {
+		png_palette[i].red   = raw_image->palette[i].red;
+		png_palette[i].green = raw_image->palette[i].green;
+		png_palette[i].blue  = raw_image->palette[i].blue;
+	}
+	png_set_PLTE(img.png, img.info, png_palette, raw_image->num_colors);
+	free(png_palette);
+
+	if (opts->fix)
+		set_text(&img, png_options);
+
+	png_write_info(img.png, img.info);
+
+	png_write_image(img.png, (png_byte **) raw_image->data);
+	png_write_end(img.png, NULL);
+
+	png_destroy_write_struct(&img.png, &img.info);
+	fclose(f);
+
+	if (opts->debug)
+		free(outfile);
+}
+
+void destroy_raw_image(struct RawIndexedImage **raw_image_ptr_ptr)
+{
+	int y;
+	struct RawIndexedImage *raw_image = *raw_image_ptr_ptr;
+
+	for (y = 0; y < raw_image->height; y++)
+		free(raw_image->data[y]);
+
+	free(raw_image->data);
+	free(raw_image->palette);
+	free(raw_image);
+	*raw_image_ptr_ptr = NULL;
+}
+
+static void initialize_png(struct PNGImage *img, FILE *f)
+{
 	img->png = png_create_read_struct(PNG_LIBPNG_VER_STRING,
 					  NULL, NULL, NULL);
 	if (!img->png)
@@ -34,7 +159,6 @@ void input_png_file(const struct Options opts, struct PNGImage *img)
 	if (!img->info)
 		errx(1, "Creating png info structure failed");
 
-	/* TODO: Better error handling here? */
 	if (setjmp(png_jmpbuf(img->png)))
 		exit(1);
 
@@ -46,125 +170,415 @@ void input_png_file(const struct Options opts, struct PNGImage *img)
 	img->height = png_get_image_height(img->png, img->info);
 	img->depth  = png_get_bit_depth(img->png, img->info);
 	img->type   = png_get_color_type(img->png, img->info);
+}
 
-	if (img->type & PNG_COLOR_MASK_ALPHA)
+static void read_png(struct PNGImage *img);
-		png_set_strip_alpha(img->png);
+static struct RawIndexedImage *create_raw_image(int width, int height,
+						int num_colors);
+static void set_raw_image_palette(struct RawIndexedImage *raw_image,
+				  const png_color *palette, int num_colors);
 
-	if (img->depth != depth) {
+static struct RawIndexedImage *indexed_png_to_raw(struct PNGImage *img)
-		if (opts.verbose) {
+{
-			warnx("Image bit depth is not %i (is %i).", depth,
+	struct RawIndexedImage *raw_image;
-			      img->depth);
+	png_color *palette;
-		}
+	int colors_in_PLTE;
-	}
+	int colors_in_new_palette;
+	png_byte *trans_alpha;
+	int num_trans;
+	png_color_16 *trans_color;
+	png_color *original_palette;
+	uint8_t *old_to_new_palette;
+	int i, x, y;
 
-	if (img->type == PNG_COLOR_TYPE_GRAY) {
+	if (img->depth < 8)
-		if (img->depth < 8)
+		png_set_packing(img->png);
-			png_set_expand_gray_1_2_4_to_8(img->png);
 
-		png_set_gray_to_rgb(img->png);
+	png_get_PLTE(img->png, img->info, &palette, &colors_in_PLTE);
-	} else {
-		if (img->depth < 8)
-			png_set_expand_gray_1_2_4_to_8(img->png);
 
-		has_palette = png_get_PLTE(img->png, img->info, &palette,
+	raw_image = create_raw_image(img->width, img->height, colors);
-					   &colors);
-	}
 
+	/*
+	 * Transparent palette entries are removed, and the palette is collapsed.
+	 * Transparent pixels are then replaced with palette index 0.
+	 * This way, an indexed PNG can contain transparent pixels in *addition*
+	 * to 4 normal colors.
+	 */
 	if (png_get_tRNS(img->png, img->info, &trans_alpha, &num_trans,
-			 &trans_values)) {
+			 &trans_color)) {
-		if (img->type == PNG_COLOR_TYPE_PALETTE) {
+		original_palette = palette;
-			full_alpha = malloc(sizeof(bool) * num_trans);
+		palette = malloc(sizeof(png_color) * colors_in_PLTE);
+		colors_in_new_palette = 0;
+		old_to_new_palette = malloc(sizeof(uint8_t) * colors_in_PLTE);
 
-			for (i = 0; i < num_trans; i++) {
+		for (i = 0; i < num_trans; i++) {
-				if (trans_alpha[i] > 0)
+			if (trans_alpha[i] == 0) {
-					full_alpha[i] = false;
+				old_to_new_palette[i] = 0;
-				else
+			} else {
-					full_alpha[i] = true;
+				old_to_new_palette[i] = colors_in_new_palette;
+				palette[colors_in_new_palette++] =
+					original_palette[i];
 			}
-
+		}
-			for (i = 0; i < num_trans; i++) {
+		for (i = num_trans; i < colors_in_PLTE; i++) {
-				if (full_alpha[i]) {
+			old_to_new_palette[i] = colors_in_new_palette;
-					palette[i].red   = 0xFF;
+			palette[colors_in_new_palette++] = original_palette[i];
-					palette[i].green = 0x00;
-					palette[i].blue  = 0xFF;
-					/*
-					 * Set to the lightest color in the
-					 * palette.
-					 */
-				}
-			}
-
-			free(full_alpha);
-		} else {
-			/* Set to the lightest color in the image. */
 		}
 
-		png_free_data(img->png, img->info, PNG_FREE_TRNS, -1);
+		if (colors_in_new_palette != colors_in_PLTE) {
-	}
+			palette = realloc(palette,
+					  sizeof(png_color) *
+					  colors_in_new_palette);
+		}
 
-	if (has_palette) {
-		/* Make sure palette only has the amount of colors you want. */
-	} else {
 		/*
-		 * Eventually when this copies colors from the image itself,
+		 * Setting and validating palette before reading
-		 * make sure order is lightest to darkest.
+		 * allows us to error out *before* doing the data
+		 * transformation if the palette is too long.
 		 */
-		palette = malloc(sizeof(png_color) * colors);
+		set_raw_image_palette(raw_image, palette,
+				      colors_in_new_palette);
+		read_png(img);
 
-		if (strcmp(opts.infile, "rgb.png") == 0) {
+		for (y = 0; y < img->height; y++) {
-			palette[0].red   = 0xFF;
+			for (x = 0; x < img->width; x++) {
-			palette[0].green = 0xEF;
+				raw_image->data[y][x] =
-			palette[0].blue  = 0xFF;
+					old_to_new_palette[img->data[y][x]];
+			}
+		}
 
-			palette[1].red   = 0xF7;
+		free(old_to_new_palette);
-			palette[1].green = 0xF7;
+	} else {
-			palette[1].blue  = 0x8C;
+		set_raw_image_palette(raw_image, palette, colors_in_PLTE);
+		read_png(img);
 
-			palette[2].red   = 0x94;
+		for (y = 0; y < img->height; y++) {
-			palette[2].green = 0x94;
+			for (x = 0; x < img->width; x++)
-			palette[2].blue  = 0xC6;
+				raw_image->data[y][x] = img->data[y][x];
-
-			palette[3].red   = 0x39;
-			palette[3].green = 0x39;
-			palette[3].blue  = 0x84;
-		} else {
-			palette[0].red   = 0xFF;
-			palette[0].green = 0xFF;
-			palette[0].blue  = 0xFF;
-
-			palette[1].red   = 0xA9;
-			palette[1].green = 0xA9;
-			palette[1].blue  = 0xA9;
-
-			palette[2].red   = 0x55;
-			palette[2].green = 0x55;
-			palette[2].blue  = 0x55;
-
-			palette[3].red   = 0x00;
-			palette[3].green = 0x00;
-			palette[3].blue  = 0x00;
 		}
 	}
 
-	/*
+	return raw_image;
-	 * Also unfortunately, this sets it at 8 bit, and I can't find any
+}
-	 * option to reduce to 2 or 1 bit.
-	 */
-#if PNG_LIBPNG_VER < 10402
-	png_set_dither(img->png, palette, colors, colors, NULL, 1);
-#else
-	png_set_quantize(img->png, palette, colors, colors, NULL, 1);
-#endif
 
-	if (!has_palette) {
+static struct RawIndexedImage *grayscale_png_to_raw(struct PNGImage *img)
-		png_set_PLTE(img->png, img->info, palette, colors);
+{
-		free(palette);
+	if (img->depth < 8)
+		png_set_expand_gray_1_2_4_to_8(img->png);
+
+	png_set_gray_to_rgb(img->png);
+	return truecolor_png_to_raw(img);
+}
+
+static void rgba_png_palette(struct PNGImage *img,
+			     png_color **palette_ptr_ptr, int *num_colors);
+static struct RawIndexedImage
+	*processed_rgba_png_to_raw(const struct PNGImage *img,
+				   const png_color *palette,
+				   int colors_in_palette);
+
+static struct RawIndexedImage *truecolor_png_to_raw(struct PNGImage *img)
+{
+	struct RawIndexedImage *raw_image;
+	png_color *palette;
+	int colors_in_palette;
+
+	if (img->depth == 16) {
+#if PNG_LIBPNG_VER >= 10504
+		png_set_scale_16(img->png);
+#else
+		png_set_strip_16(img->png);
+#endif
 	}
 
+	if (!(img->type & PNG_COLOR_MASK_ALPHA)) {
+		if (png_get_valid(img->png, img->info, PNG_INFO_tRNS))
+			png_set_tRNS_to_alpha(img->png);
+		else
+			png_set_add_alpha(img->png, 0xFF, PNG_FILLER_AFTER);
+	}
+
+	read_png(img);
+
+	rgba_png_palette(img, &palette, &colors_in_palette);
+	raw_image = processed_rgba_png_to_raw(img, palette, colors_in_palette);
+
+	free(palette);
+
+	return raw_image;
+}
+
+static void rgba_PLTE_palette(struct PNGImage *img,
+			      png_color **palette_ptr_ptr, int *num_colors);
+static void rgba_build_palette(struct PNGImage *img,
+			       png_color **palette_ptr_ptr, int *num_colors);
+
+static void rgba_png_palette(struct PNGImage *img,
+			     png_color **palette_ptr_ptr, int *num_colors)
+{
+	if (png_get_valid(img->png, img->info, PNG_INFO_PLTE))
+		rgba_PLTE_palette(img, palette_ptr_ptr, num_colors);
+	else
+		rgba_build_palette(img, palette_ptr_ptr, num_colors);
+}
+
+static void rgba_PLTE_palette(struct PNGImage *img,
+			      png_color **palette_ptr_ptr, int *num_colors)
+{
+	png_get_PLTE(img->png, img->info, palette_ptr_ptr, num_colors);
 	/*
-	 * If other useless chunks exist (sRGB, bKGD, pHYs, gAMA, cHRM, iCCP,
+	 * Lets us free the palette manually instead of leaving it to libpng,
-	 * etc.) offer to remove?
+	 * which lets us handle a PLTE and a built palette the same way.
 	 */
+	png_data_freer(img->png, img->info,
+		       PNG_USER_WILL_FREE_DATA, PNG_FREE_PLTE);
+}
+
+static void update_built_palette(png_color *palette,
+				 const png_color *pixel_color, png_byte alpha,
+				 int *num_colors, bool *only_grayscale);
+static int fit_grayscale_palette(png_color *palette, int *num_colors);
+static void order_color_palette(png_color *palette, int num_colors);
+
+static void rgba_build_palette(struct PNGImage *img,
+			       png_color **palette_ptr_ptr, int *num_colors)
+{
+	png_color *palette;
+	int y, value_index;
+	png_color cur_pixel_color;
+	png_byte cur_alpha;
+	bool only_grayscale = true;
+
+	/*
+	 * By filling the palette up with black by default, if the image
+	 * doesn't have enough colors, the palette gets padded with black.
+	 */
+	*palette_ptr_ptr = calloc(colors, sizeof(png_color));
+	palette = *palette_ptr_ptr;
+	*num_colors = 0;
+
+	for (y = 0; y < img->height; y++) {
+		value_index = 0;
+		while (value_index < img->width * 4) {
+			cur_pixel_color.red   = img->data[y][value_index++];
+			cur_pixel_color.green = img->data[y][value_index++];
+			cur_pixel_color.blue  = img->data[y][value_index++];
+			cur_alpha = img->data[y][value_index++];
+
+			update_built_palette(palette, &cur_pixel_color,
+					     cur_alpha,
+					     num_colors, &only_grayscale);
+		}
+	}
+
+	/* In order not to count 100% transparent images as grayscale. */
+	only_grayscale = *num_colors ? only_grayscale : false;
+
+	if (!only_grayscale || !fit_grayscale_palette(palette, num_colors))
+		order_color_palette(palette, *num_colors);
+}
+
+static void update_built_palette(png_color *palette,
+				 const png_color *pixel_color, png_byte alpha,
+				 int *num_colors, bool *only_grayscale)
+{
+	bool color_exists;
+	png_color cur_palette_color;
+	int i;
+
+	/*
+	 * Transparent pixels don't count toward the palette,
+	 * as they'll be replaced with color #0 later.
+	 */
+	if (alpha == 0)
+		return;
+
+	if (*only_grayscale && !(pixel_color->red == pixel_color->green &&
+				 pixel_color->red == pixel_color->blue)) {
+		*only_grayscale = false;
+	}
+
+	color_exists = false;
+	for (i = 0; i < *num_colors; i++) {
+		cur_palette_color = palette[i];
+		if (pixel_color->red   == cur_palette_color.red   &&
+		    pixel_color->green == cur_palette_color.green &&
+		    pixel_color->blue  == cur_palette_color.blue) {
+			color_exists = true;
+			break;
+		}
+	}
+	if (!color_exists) {
+		if (*num_colors == colors) {
+			err(1, "Too many colors in input PNG file to fit into a %d-bit palette (max %d).",
+			    depth, colors);
+		}
+		palette[*num_colors] = *pixel_color;
+		(*num_colors)++;
+	}
+}
+
+static int fit_grayscale_palette(png_color *palette, int *num_colors)
+{
+	int interval = 256 / colors;
+	png_color *fitted_palette = malloc(sizeof(png_color) * colors);
+	bool *set_indices = calloc(colors, sizeof(bool));
+	int i, shade_index;
+
+	fitted_palette[0].red   = 0xFF;
+	fitted_palette[0].green = 0xFF;
+	fitted_palette[0].blue  = 0xFF;
+	fitted_palette[colors - 1].red   = 0;
+	fitted_palette[colors - 1].green = 0;
+	fitted_palette[colors - 1].blue  = 0;
+	if (colors == 4) {
+		fitted_palette[1].red   = 0xA9;
+		fitted_palette[1].green = 0xA9;
+		fitted_palette[1].blue  = 0xA9;
+		fitted_palette[2].red   = 0x55;
+		fitted_palette[2].green = 0x55;
+		fitted_palette[2].blue  = 0x55;
+	}
+
+	for (i = 0; i < *num_colors; i++) {
+		shade_index = colors - 1 - palette[i].red / interval;
+		if (set_indices[shade_index]) {
+			free(fitted_palette);
+			free(set_indices);
+			return false;
+		}
+		fitted_palette[shade_index] = palette[i];
+		set_indices[shade_index] = true;
+	}
+
+	for (i = 0; i < colors; i++)
+		palette[i] = fitted_palette[i];
+
+	*num_colors = colors;
+
+	free(fitted_palette);
+	free(set_indices);
+	return true;
+}
+
+/* A combined struct is needed to sort csolors in order of luminance. */
+struct ColorWithLuminance {
+	png_color color;
+	int luminance;
+};
+
+static int compare_luminance(const void *a, const void *b)
+{
+	const struct ColorWithLuminance *x, *y;
+
+	x = (const struct ColorWithLuminance *)a;
+	y = (const struct ColorWithLuminance *)b;
+
+	return y->luminance - x->luminance;
+}
+
+static void order_color_palette(png_color *palette, int num_colors)
+{
+	int i;
+	struct ColorWithLuminance *palette_with_luminance =
+		malloc(sizeof(struct ColorWithLuminance) * num_colors);
+
+	for (i = 0; i < num_colors; i++) {
+		/*
+		 * Normally this would be done with floats, but since it's only
+		 * used for comparison, we might as well use integer math.
+		 */
+		palette_with_luminance[i].color = palette[i];
+		palette_with_luminance[i].luminance = 2126 * palette[i].red   +
+						      7152 * palette[i].green +
+						       722 * palette[i].blue;
+	}
+	qsort(palette_with_luminance, num_colors,
+	      sizeof(struct ColorWithLuminance), compare_luminance);
+	for (i = 0; i < num_colors; i++)
+		palette[i] = palette_with_luminance[i].color;
+
+	free(palette_with_luminance);
+}
+
+static void put_raw_image_pixel(struct RawIndexedImage *raw_image,
+				const struct PNGImage *img,
+				int *value_index, int x, int y,
+				const png_color *palette,
+				int colors_in_palette);
+
+static struct RawIndexedImage
+	*processed_rgba_png_to_raw(const struct PNGImage *img,
+				   const png_color *palette,
+				   int colors_in_palette)
+{
+	struct RawIndexedImage *raw_image;
+	int x, y, value_index;
+
+	raw_image = create_raw_image(img->width, img->height, colors);
+
+	set_raw_image_palette(raw_image, palette, colors_in_palette);
+
+	for (y = 0; y < img->height; y++) {
+		x = raw_image->width - 1;
+		value_index = img->width * 4 - 1;
+
+		while (x >= 0) {
+			put_raw_image_pixel(raw_image, img,
+					    &value_index, x, y,
+					    palette, colors_in_palette);
+			x--;
+		}
+	}
+
+	return raw_image;
+}
+
+static uint8_t palette_index_of(const png_color *palette,
+				int num_colors, const png_color *color);
+
+static void put_raw_image_pixel(struct RawIndexedImage *raw_image,
+				const struct PNGImage *img,
+				int *value_index, int x, int y,
+				const png_color *palette,
+				int colors_in_palette)
+{
+	png_color pixel_color;
+	png_byte alpha;
+
+	alpha = img->data[y][*value_index];
+	if (alpha == 0) {
+		raw_image->data[y][x] = 0;
+		*value_index -= 4;
+	} else {
+		(*value_index)--;
+		pixel_color.blue  = img->data[y][(*value_index)--];
+		pixel_color.green = img->data[y][(*value_index)--];
+		pixel_color.red   = img->data[y][(*value_index)--];
+		raw_image->data[y][x] = palette_index_of(palette,
+							 colors_in_palette,
+							 &pixel_color);
+	}
+}
+
+static uint8_t palette_index_of(const png_color *palette,
+				int num_colors, const png_color *color)
+{
+	uint8_t i;
+
+	for (i = 0; i < num_colors; i++) {
+		if (palette[i].red   == color->red   &&
+		    palette[i].green == color->green &&
+		    palette[i].blue  == color->blue) {
+			return i;
+		}
+	}
+	errx(1, "The input PNG file contains colors that don't appear in its embedded palette.");
+}
+
+static void read_png(struct PNGImage *img)
+{
+	int y;
 
 	png_read_update_info(img->png, img->info);
 
@@ -174,35 +588,78 @@ void input_png_file(const struct Options opts, struct PNGImage *img)
 
 	png_read_image(img->png, img->data);
 	png_read_end(img->png, img->info);
-
-	fclose(f);
 }
 
-void get_text(struct PNGImage *png)
+static struct RawIndexedImage *create_raw_image(int width, int height,
+						int num_colors)
+{
+	struct RawIndexedImage *raw_image;
+	int y;
+
+	raw_image = malloc(sizeof(struct RawIndexedImage));
+
+	raw_image->width = width;
+	raw_image->height = height;
+	raw_image->num_colors = num_colors;
+
+	raw_image->palette = malloc(sizeof(struct RGBColor) * num_colors);
+
+	raw_image->data = malloc(sizeof(uint8_t *) * height);
+	for (y = 0; y < height; y++)
+		raw_image->data[y] = malloc(sizeof(uint8_t) * width);
+
+	return raw_image;
+}
+
+static void set_raw_image_palette(struct RawIndexedImage *raw_image,
+				  const png_color *palette, int num_colors)
+{
+	int i;
+
+	if (num_colors > raw_image->num_colors) {
+		errx(1, "Too many colors in input PNG file's palette to fit into a %d-bit palette (%d in input palette, max %d).",
+		     raw_image->num_colors >> 1,
+		     num_colors, raw_image->num_colors);
+	}
+
+	for (i = 0; i < num_colors; i++) {
+		raw_image->palette[i].red   = palette[i].red;
+		raw_image->palette[i].green = palette[i].green;
+		raw_image->palette[i].blue  = palette[i].blue;
+	}
+	for (i = num_colors; i < raw_image->num_colors; i++) {
+		raw_image->palette[i].red   = 0;
+		raw_image->palette[i].green = 0;
+		raw_image->palette[i].blue  = 0;
+	}
+}
+
+static void get_text(const struct PNGImage *img,
+		     struct ImageOptions *png_options)
 {
 	png_text *text;
 	int i, numtxts, numremoved;
 
-	png_get_text(png->png, png->info, &text, &numtxts);
+	png_get_text(img->png, img->info, &text, &numtxts);
 	for (i = 0; i < numtxts; i++) {
 		if (strcmp(text[i].key, "h") == 0 && !*text[i].text) {
-			png->horizontal = true;
+			png_options->horizontal = true;
-			png_free_data(png->png, png->info, PNG_FREE_TEXT, i);
+			png_free_data(img->png, img->info, PNG_FREE_TEXT, i);
 		} else if (strcmp(text[i].key, "x") == 0) {
-			png->trim = strtoul(text[i].text, NULL, 0);
+			png_options->trim = strtoul(text[i].text, NULL, 0);
-			png_free_data(png->png, png->info, PNG_FREE_TEXT, i);
+			png_free_data(img->png, img->info, PNG_FREE_TEXT, i);
 		} else if (strcmp(text[i].key, "t") == 0) {
-			png->mapfile = text[i].text;
+			png_options->mapfile = text[i].text;
-			png_free_data(png->png, png->info, PNG_FREE_TEXT, i);
+			png_free_data(img->png, img->info, PNG_FREE_TEXT, i);
 		} else if (strcmp(text[i].key, "T") == 0 && !*text[i].text) {
-			png->mapout = true;
+			png_options->mapout = true;
-			png_free_data(png->png, png->info, PNG_FREE_TEXT, i);
+			png_free_data(img->png, img->info, PNG_FREE_TEXT, i);
 		} else if (strcmp(text[i].key, "p") == 0) {
-			png->palfile = text[i].text;
+			png_options->palfile = text[i].text;
-			png_free_data(png->png, png->info, PNG_FREE_TEXT, i);
+			png_free_data(img->png, img->info, PNG_FREE_TEXT, i);
 		} else if (strcmp(text[i].key, "P") == 0 && !*text[i].text) {
-			png->palout = true;
+			png_options->palout = true;
-			png_free_data(png->png, png->info, PNG_FREE_TEXT, i);
+			png_free_data(img->png, img->info, PNG_FREE_TEXT, i);
 		}
 	}
 
@@ -218,106 +675,64 @@ void get_text(struct PNGImage *png)
 		text[i].text = text[i + numremoved].text;
 		text[i].compression = text[i + numremoved].compression;
 	}
-	png_set_text(png->png, png->info, text, numtxts - numremoved);
+	png_set_text(img->png, img->info, text, numtxts - numremoved);
 }
 
-void set_text(const struct PNGImage *png)
+static void set_text(const struct PNGImage *img,
+		     const struct ImageOptions *png_options)
 {
 	png_text *text;
 	char buffer[3];
 
 	text = malloc(sizeof(png_text));
 
-	if (png->horizontal) {
+	if (png_options->horizontal) {
 		text[0].key = "h";
 		text[0].text = "";
 		text[0].compression = PNG_TEXT_COMPRESSION_NONE;
-		png_set_text(png->png, png->info, text, 1);
+		png_set_text(img->png, img->info, text, 1);
 	}
-	if (png->trim) {
+	if (png_options->trim) {
 		text[0].key = "x";
-		snprintf(buffer, 3, "%d", png->trim);
+		snprintf(buffer, 3, "%d", png_options->trim);
 		text[0].text = buffer;
 		text[0].compression = PNG_TEXT_COMPRESSION_NONE;
-		png_set_text(png->png, png->info, text, 1);
+		png_set_text(img->png, img->info, text, 1);
 	}
-	if (*png->mapfile) {
+	if (*png_options->mapfile) {
 		text[0].key = "t";
 		text[0].text = "";
 		text[0].compression = PNG_TEXT_COMPRESSION_NONE;
-		png_set_text(png->png, png->info, text, 1);
+		png_set_text(img->png, img->info, text, 1);
 	}
-	if (png->mapout) {
+	if (png_options->mapout) {
 		text[0].key = "T";
 		text[0].text = "";
 		text[0].compression = PNG_TEXT_COMPRESSION_NONE;
-		png_set_text(png->png, png->info, text, 1);
+		png_set_text(img->png, img->info, text, 1);
 	}
-	if (*png->palfile) {
+	if (*png_options->palfile) {
 		text[0].key = "p";
 		text[0].text = "";
 		text[0].compression = PNG_TEXT_COMPRESSION_NONE;
-		png_set_text(png->png, png->info, text, 1);
+		png_set_text(img->png, img->info, text, 1);
 	}
-	if (png->palout) {
+	if (png_options->palout) {
 		text[0].key = "P";
 		text[0].text = "";
 		text[0].compression = PNG_TEXT_COMPRESSION_NONE;
-		png_set_text(png->png, png->info, text, 1);
+		png_set_text(img->png, img->info, text, 1);
 	}
 
 	free(text);
 }
 
-void output_png_file(const struct Options opts, const struct PNGImage *png)
+static void free_png_data(const struct PNGImage *img)
-{
-	FILE *f;
-	char *outfile;
-	png_struct *img;
-
-	/*
-	 * TODO: Variable outfile is for debugging purposes. Eventually,
-	 * opts.infile will be used directly.
-	 */
-	if (opts.debug) {
-		outfile = malloc(strlen(opts.infile) + 5);
-		strcpy(outfile, opts.infile);
-		strcat(outfile, ".out");
-	} else {
-		outfile = opts.infile;
-	}
-
-	f = fopen(outfile, "wb");
-	if (!f)
-		err(1, "Opening output png file '%s' failed", outfile);
-
-	img = png_create_write_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
-	if (!img)
-		errx(1, "Creating png structure failed");
-
-	/* TODO: Better error handling here? */
-	if (setjmp(png_jmpbuf(img)))
-		exit(1);
-
-	png_init_io(img, f);
-
-	png_write_info(img, png->info);
-
-	png_write_image(img, png->data);
-	png_write_end(img, NULL);
-
-	fclose(f);
-
-	if (opts.debug)
-		free(outfile);
-}
-
-void free_png_data(const struct PNGImage *png)
 {
 	int y;
 
-	for (y = 0; y < png->height; y++)
+	for (y = 0; y < img->height; y++)
-		free(png->data[y]);
+		free(img->data[y]);
 
-	free(png->data);
+	free(img->data);
 }

src/gfx/rgbgfx.1

@@ -24,7 +24,28 @@
 The
 .Nm
 program converts PNG images into the Nintendo Game Boy's planar tile format.
-The arguments are as follows:
+
+The resulting colors and their palette indices are determined differently
+depending on the input PNG file:
+.Bl -dash -width Ds
+.It
+If the file has an embedded palette, that palette's color and order are used.
+.It
+If not, and the image only contains shades of gray, rgbgfx maps them to the
+indices appropriate for each shade. Any undetermined indices are set to
+respective default shades of gray. For example: if the bit depth is 2 and the
+image contains light gray and black, they become the second and fourth colors -
+and the first and third colors get set to default white and dark gray. If the
+image has multiple shades that map to the same index, the palette is instead
+determined as if the image had color.
+.It
+If the image has color (or the grayscale method failed), the colors are sorted
+from lightest to darkest.
+.El
+
+The input image may not contain more colors than the selected bit depth
+allows. Transparent pixels are set to palette index 0.
+.Sh ARGUMENTS
 .Bl -tag -width Ds
 .It Fl D
 Debug features are enabled.
@@ -33,24 +54,25 @@ Fix the input PNG file to be a correctly indexed image.
 .It Fl F
 Same as
 .Fl f ,
-but additionally, the input PNG file is fixed to have its parameters match the
+but additionally, the supplied command line parameters are saved within the PNG
-command line's parameters.
+and will be loaded and automatically used next time.
 .It Fl d Ar depth
-The bitdepth of the output image (either 1 or 2).
+The bit depth of the output image (either 1 or 2).
-By default, the bitdepth is 2 (two bits per pixel).
+By default, the bit depth is 2 (two bits per pixel).
 .It Fl h
 Lay out tiles horizontally rather than vertically.
 .It Fl o Ar outfile
 The name of the output file.
 .It Fl p Ar palfile
-Raw bytes (8 bytes for two bits per pixel, 4 bytes for one bit per pixel)
+Output the image's palette in standard GBC palette format - bytes (8 bytes for
-containing the RGB15 values in the little-endian byte order and then ordered
+two bits per pixel, 4 bytes for one bit per pixel) containing the RGB15 values
-from lightest to darkest.
+in little-endian byte order. If the palette contains too few colors, the
+remaining entries are set to black.
 .It Fl P
 Same as
 .Fl p ,
-but the pallete file output name is made by taking the input filename,
+but the palette file output name is made by taking the input PNG file's
-removing the file extension, and appending
+filename, removing the file extension, and appending
 .Pa .pal .
 .It Fl t Ar mapfile
 If any tiles are the same, don't place the repeat tiles in the output file, and
@@ -73,7 +95,7 @@ the PNG file don't match.
 Trim the end of the output file by this many tiles.
 .El
 .Sh EXAMPLES
-The following will take a PNG file with a bitdepth of 1, 2, or 8, and output
+The following will take a PNG file with a bit depth of 1, 2, or 8, and output
 planar 2bpp data:
 .Pp
 .D1 $ rgbgfx -o out.2bpp in.png

src/link/assign.c

@@ -74,6 +74,10 @@ static void do_max_bank(enum eSectionType Type, int32_t nBank)
 		if (nBank > MaxVBankUsed)
 			MaxVBankUsed = nBank;
 		break;
+	case SECT_ROM0:
+	case SECT_WRAM0:
+	case SECT_OAM:
+	case SECT_HRAM:
 	default:
 		break;
 	}
@@ -494,7 +498,6 @@ void SetLinkerscriptName(char *tzLinkerscriptFile)
 
 void AssignSections(void)
 {
-	int32_t i;
 	struct sSection *pSection;
 
 	MaxBankUsed = 0;
@@ -503,7 +506,7 @@ void AssignSections(void)
 	 * Initialize the memory areas
 	 */
 
-	for (i = 0; i < BANK_INDEX_MAX; i += 1) {
+	for (int32_t i = 0; i < BANK_INDEX_MAX; i += 1) {
 		BankFree[i] = malloc(sizeof(*BankFree[i]));
 
 		if (!BankFree[i]) {
@@ -617,6 +620,9 @@ void AssignSections(void)
 				     pSection->nOrg, pSection->nBank);
 			}
 			break;
+		default:
+			errx(1, "%s: Internal error: Type %d", __func__,
+			     pSection->Type);
 		}
 	}
 
@@ -660,6 +666,10 @@ void AssignSections(void)
 			do_max_bank(pSection->Type, pSection->nBank);
 			break;
 
+		case SECT_ROM0:
+		case SECT_WRAM0:
+		case SECT_OAM:
+		case SECT_HRAM:
 		default: /* Handle other sections later */
 			break;
 		}

src/link/lexer.l

@@ -23,7 +23,7 @@
 
 #include "types.h"
 
-extern int yyparse();
+extern int yyparse(void);
 
 /* File include stack. */
 
@@ -179,13 +179,13 @@ void script_PrintFileStack(void)
 	fprintf(stderr, "%s(%d)", linkerscript_path, include_line[i]);
 }
 
-noreturn void script_fatalerror(const char *fmt, ...)
+noreturn_ void script_fatalerror(const char *fmt, ...)
 {
 	va_list args;
 	va_start(args, fmt);
 	fprintf(stderr, "error: ");
 	script_PrintFileStack();
-	fprintf(stderr, ":\n\t");
+	fprintf(stderr, ":\n    ");
 	vfprintf(stderr, fmt, args);
 	fprintf(stderr, "\n");
 	va_end(args);

src/link/mapfile.c

@@ -120,6 +120,10 @@ void MapfileWriteSection(const struct sSection *pSect)
 	for (i = 0; i < pSect->nNumberOfSymbols; i += 1) {
 		const struct sSymbol *pSym = pSect->tSymbols[i];
 
+		/* Don't print '@' */
+		if (strcmp(pSym->pzName, "@") == 0)
+			continue;
+
 		if ((pSym->pSection == pSect) && (pSym->Type != SYM_IMPORT)) {
 			if (mf) {
 				fprintf(mf, "           $%04X = %s\n",

src/link/object.c

@@ -36,14 +36,14 @@ uint8_t oReadLib;
  */
 static int32_t readlong(FILE *f)
 {
-	int32_t r;
+	uint32_t r;
 
-	r = fgetc(f);
+	r = ((uint32_t)(uint8_t)fgetc(f));
-	r |= fgetc(f) << 8;
+	r |= ((uint32_t)(uint8_t)fgetc(f)) << 8;
-	r |= fgetc(f) << 16;
+	r |= ((uint32_t)(uint8_t)fgetc(f)) << 16;
-	r |= fgetc(f) << 24;
+	r |= ((uint32_t)(uint8_t)fgetc(f)) << 24;
 
-	return r;
+	return (int32_t)r;
 }
 
 /*

src/link/output.c

@@ -110,46 +110,53 @@ void Output(void)
 	FILE *f_overlay = NULL;
 
 	/*
-	 * Apply overlay
+	 * Load overlay
+	 */
+
+	if (tzOverlayname) {
+		f_overlay = fopen(tzOverlayname, "rb");
+
+		if (!f_overlay) {
+			errx(1, "Failed to open overlay file %s\n",
+			     tzOverlayname);
+		}
+
+		fseek(f_overlay, 0, SEEK_END);
+
+		if (ftell(f_overlay) % 0x4000 != 0)
+			errx(1, "Overlay file must be aligned to 0x4000 bytes.");
+
+		MaxOverlayBank = (ftell(f_overlay) / 0x4000) - 1;
+
+		if (MaxOverlayBank < 1)
+			errx(1, "Overlay file must be at least 0x8000 bytes.");
+
+		if (MaxOverlayBank > MaxBankUsed)
+			MaxBankUsed = MaxOverlayBank;
+	}
+
+	/*
+	 * Write ROM.
 	 */
 
 	f = fopen(tzOutname, "wb");
-
 	if (f != NULL) {
-		if (tzOverlayname) {
-			f_overlay = fopen(tzOverlayname, "rb");
-
-			if (!f_overlay) {
-				errx(1, "Failed to open overlay file %s\n",
-				     tzOverlayname);
-			}
-
-			fseek(f_overlay, 0, SEEK_END);
-
-			if (ftell(f_overlay) % 0x4000 != 0)
-				errx(1, "Overlay file must be aligned to 0x4000 bytes.");
-
-			MaxOverlayBank = (ftell(f_overlay) / 0x4000) - 1;
-
-			if (MaxOverlayBank < 1)
-				errx(1, "Overlay file must be at least 0x8000 bytes.");
-
-			if (MaxOverlayBank > MaxBankUsed)
-				MaxBankUsed = MaxOverlayBank;
-		}
-
 		writehome(f, f_overlay);
 		for (i = 1; i <= MaxBankUsed; i += 1)
 			writebank(f, f_overlay, i);
 
 		fclose(f);
-
-		if (tzOverlayname)
-			fclose(f_overlay);
 	}
 
 	/*
-	 * Add regular sections
+	 * Close overlay
+	 */
+
+	if (tzOverlayname)
+		fclose(f_overlay);
+
+	/*
+	 * Add regular sections to map and sym files.
 	 */
 
 	for (i = BANK_INDEX_WRAM0; i < BANK_INDEX_MAX; i++) {

src/link/parser.y

@@ -14,7 +14,7 @@
 
 #include "link/script.h"
 
-int yylex();
+int yylex(void);
 void yyerror(char *);
 
 extern int yylineno;
@@ -107,8 +107,8 @@ statement:
 
 %%
 
-extern int yylex();
+extern int yylex(void);
-extern int yyparse();
+extern int yyparse(void);
 
 int yywrap(void)
 {

src/link/patch.c

@@ -267,6 +267,7 @@ void Patch(void)
 		pPatch = pSect->pPatches;
 		while (pPatch) {
 			int32_t t;
+			int32_t nPatchOrg;
 
 			nPC = pSect->nOrg + pPatch->nOffset;
 			t = calcrpn(pPatch);
@@ -306,6 +307,26 @@ void Patch(void)
 				pSect->pData[pPatch->nOffset + 3] =
 					(t >> 24) & 0xFF;
 				break;
+			case PATCH_BYTE_JR:
+				/* Calculate absolute address of the patch */
+				nPatchOrg = pSect->nOrg + pPatch->nOffset;
+
+				/* t contains the destination of the jump */
+				t = (int16_t)((t & 0xFFFF) - (nPatchOrg + 1));
+
+				if (t >= -128 && t <= 127) {
+					t &= 0xFF;
+					pSect->pData[pPatch->nOffset] =
+						(uint8_t)t;
+				} else {
+					errx(1,
+					     "%s(%ld) : Value must be 8-bit",
+					     pPatch->pzFilename,
+					     pPatch->nLineNo);
+				}
+				break;
+			default:
+				errx(1, "%s: Internal error.", __func__);
 			}
 
 			pPatch = pPatch->pNext;

src/link/rgblink.1

@@ -57,7 +57,7 @@ Write a symbol file to the given filename.
 .It Fl O Ar overlayfile
 The ROM image to overlay sections over.
 When an overlay ROM is provided, all sections must be fixed.
-This may be used to patch an existing binray.
+This may be used to patch an existing binary.
 .It Fl o Ar outfile
 Write ROM image to the given filename.
 .It Fl p Ar pad_value

src/link/script.c

@@ -85,59 +85,59 @@ void script_InitSections(void)
 	}
 }
 
-void script_SetCurrentSectionType(const char *type, uint32_t bank)
+void script_SetCurrentSectionType(const char *type, uint32_t bank_num)
 {
 	if (strcmp(type, "ROM0") == 0) {
-		if (bank != 0)
+		if (bank_num != 0)
 			errx(1, "Trying to assign a bank number to ROM0.\n");
 		current_bank = BANK_INDEX_ROM0;
 		current_real_bank = 0;
 		return;
 	} else if (strcmp(type, "ROMX") == 0) {
-		if (bank == 0)
+		if (bank_num == 0)
 			errx(1, "ROMX index can't be 0.\n");
-		if (bank > BANK_COUNT_ROMX) {
+		if (bank_num > BANK_COUNT_ROMX) {
-			errx(1, "ROMX index too big (%d > %d).\n", bank,
+			errx(1, "ROMX index too big (%d > %d).\n", bank_num,
 			     BANK_COUNT_ROMX);
 		}
-		current_bank = BANK_INDEX_ROMX + bank - 1;
+		current_bank = BANK_INDEX_ROMX + bank_num - 1;
-		current_real_bank = bank;
+		current_real_bank = bank_num;
 		return;
 	} else if (strcmp(type, "VRAM") == 0) {
-		if (bank >= BANK_COUNT_VRAM) {
+		if (bank_num >= BANK_COUNT_VRAM) {
-			errx(1, "VRAM index too big (%d >= %d).\n", bank,
+			errx(1, "VRAM index too big (%d >= %d).\n", bank_num,
 			     BANK_COUNT_VRAM);
 		}
-		current_bank = BANK_INDEX_VRAM + bank;
+		current_bank = BANK_INDEX_VRAM + bank_num;
-		current_real_bank = bank;
+		current_real_bank = bank_num;
 		return;
 	} else if (strcmp(type, "WRAM0") == 0) {
-		if (bank != 0)
+		if (bank_num != 0)
 			errx(1, "Trying to assign a bank number to WRAM0.\n");
 
 		current_bank = BANK_INDEX_WRAM0;
 		current_real_bank = 0;
 		return;
 	} else if (strcmp(type, "WRAMX") == 0) {
-		if (bank == 0)
+		if (bank_num == 0)
 			errx(1, "WRAMX index can't be 0.\n");
-		if (bank > BANK_COUNT_WRAMX) {
+		if (bank_num > BANK_COUNT_WRAMX) {
-			errx(1, "WRAMX index too big (%d > %d).\n", bank,
+			errx(1, "WRAMX index too big (%d > %d).\n", bank_num,
 			     BANK_COUNT_WRAMX);
 		}
-		current_bank = BANK_INDEX_WRAMX + bank - 1;
+		current_bank = BANK_INDEX_WRAMX + bank_num - 1;
-		current_real_bank = bank;
+		current_real_bank = bank_num;
 		return;
 	} else if (strcmp(type, "SRAM") == 0) {
-		if (bank >= BANK_COUNT_SRAM) {
+		if (bank_num >= BANK_COUNT_SRAM) {
-			errx(1, "SRAM index too big (%d >= %d).\n", bank,
+			errx(1, "SRAM index too big (%d >= %d).\n", bank_num,
 			     BANK_COUNT_SRAM);
 		}
-		current_bank = BANK_INDEX_SRAM + bank;
+		current_bank = BANK_INDEX_SRAM + bank_num;
-		current_real_bank = bank;
+		current_real_bank = bank_num;
 		return;
 	} else if (strcmp(type, "OAM") == 0) {
-		if (bank != 0) {
+		if (bank_num != 0) {
 			errx(1, "%s: Trying to assign a bank number to OAM.\n",
 			     __func__);
 		}
@@ -145,7 +145,7 @@ void script_SetCurrentSectionType(const char *type, uint32_t bank)
 		current_real_bank = 0;
 		return;
 	} else if (strcmp(type, "HRAM") == 0) {
-		if (bank != 0) {
+		if (bank_num != 0) {
 			errx(1, "%s: Trying to assign a bank number to HRAM.\n",
 			     __func__);
 		}

src/rgbds.5

@@ -57,7 +57,9 @@ REPT    NumberOfSymbols   ; Number of symbols defined in this object file.
         LONG    LineNum   ; Line number in the file where the symbol is defined.
 
         LONG    SectionID ; The section number (of this object file) in which
-                          ; this symbol is defined.
+                          ; this symbol is defined. If it doesn't belong to any
+                          ; specific section (like a constant), this field has
+                          ; the value -1.
 
         LONG    Value     ; The symbols value. It's the offset into that
                           ; symbol's section.
@@ -113,6 +115,7 @@ REPT NumberOfSections
             BYTE    Type         ; 0 = BYTE patch.
                                  ; 1 = little endian WORD patch.
                                  ; 2 = little endian LONG patch.
+                                 ; 3 = JR offset value BYTE patch.
 
             LONG    RPNSize      ; Size of the buffer with the RPN.
                                  ; expression.

src/rgbds.7

@@ -5,7 +5,7 @@
 .\"
 .\" SPDX-License-Identifier: MIT
 .\"
-.Dd January 26, 2018
+.Dd March 7, 2018
 .Dt RGBDS 7
 .Os RGBDS Manual
 .Sh NAME
@@ -14,9 +14,11 @@
 .Sh EXAMPLES
 To get a working ROM image from a single assembly source file:
 .Pp
-.D1 $ rgbasm \-o bar.o foo.asm
+.Bd -literal -offset indent
-.D1 $ rgblink \-o baz.gb bar.o
+$ rgbasm \-o bar.o foo.asm
-.D1 $ rgbfix \-v \-p 0 baz.gb
+$ rgblink \-o baz.gb bar.o
+$ rgbfix \-v \-p 0 baz.gb
+.Ed
 .Sh SEE ALSO
 .Xr rgbasm 1 ,
 .Xr rgbfix 1 ,
@@ -41,5 +43,6 @@ implementation of rgbds.
 2017, Bentley's repository is moved to a neutral name.
 It is now maintained by a number of contributors at
 .Lk https://github.com/rednex/rgbds .
+.It
 2018, codebase relicensed under the MIT license.
 .El

test/asm/divzero-instr.out

@@ -1,2 +1,2 @@
 ERROR: divzero-instr.asm(2):
-	division by zero
+    Division by zero

test/asm/divzero-section-bank.out

@@ -1,2 +1,2 @@
 ERROR: divzero-section-bank.asm(1):
-	division by zero
+    Division by zero

test/asm/local-wrong-parent.out

@@ -1,3 +1,3 @@
 ERROR: local-wrong-parent.asm(5):
-	Not currently in the scope of 'WrongParent'
+    Not currently in the scope of 'WrongParent'
 error: Assembly aborted in pass 1 (1 errors)!

test/asm/macro-@.out

@@ -1,2 +1,2 @@
 ERROR: macro-@.asm(1) -> @(-1):
-	Macro '@' not defined
+    Macro '@' not defined

test/asm/null-in-macro.out

@@ -1,2 +1,2 @@
 ERROR: null-in-macro.asm(1):
-	Unterminated MACRO definition.
+    Unterminated MACRO definition.

test/asm/remote-local-noexist.out

@@ -1,2 +1,2 @@
 ERROR: remote-local-noexist.asm(7):
-	'Parent.child.fail' is a nonsensical reference to a nested local symbol
+    'Parent.child.fail' is a nonsensical reference to a nested local symbol

test/asm/undefined-dot.out

@@ -1,3 +1,3 @@
 ERROR: undefined-dot.asm(3):
-	'.' not defined
+    '.' not defined
 error: Assembly aborted in pass 2 (1 errors)!