From e82ad21704bf4df1806195d30d8fa2bf65f0d812 Mon Sep 17 00:00:00 2001
From: ISSOtm <eldredhabert0@gmail.com>
Date: Tue, 7 Apr 2020 21:15:55 +0200
Subject: [PATCH] Use a single byte for alignment

---
 src/asm/output.c  |  2 +-
 src/asm/section.c | 18 +++++++++---------
 src/link/object.c |  8 ++++----
 src/rgbds.5       |  3 +--
 4 files changed, 15 insertions(+), 16 deletions(-)

diff --git a/src/asm/output.c b/src/asm/output.c
index 33e944ba..f445a1bd 100644
--- a/src/asm/output.c
+++ b/src/asm/output.c
@@ -180,7 +180,7 @@ static void writesection(struct Section const *pSect, FILE *f)
 
 	fputlong(pSect->nOrg, f);
 	fputlong(pSect->nBank, f);
-	fputlong(pSect->nAlign, f);
+	fputc(pSect->nAlign, f);
 
 	if (sect_HasData(pSect->nType)) {
 		fwrite(pSect->tData, 1, pSect->size, f);
diff --git a/src/asm/section.c b/src/asm/section.c
index a919d759..d3ac304f 100644
--- a/src/asm/section.c
+++ b/src/asm/section.c
@@ -86,7 +86,7 @@ struct Section *out_FindSectionByName(const char *pzName)
  */
 static struct Section *getSection(char const *pzName, enum SectionType type,
 				  uint32_t org, uint32_t bank,
-				  uint32_t alignment, bool isUnion)
+				  uint8_t alignment, bool isUnion)
 {
 	if (bank != -1) {
 		if (type != SECTTYPE_ROMX && type != SECTTYPE_VRAM
@@ -99,15 +99,15 @@ static struct Section *getSection(char const *pzName, enum SectionType type,
 				bankranges[type][0], bankranges[type][1]);
 	}
 
-	if (alignment != 1) {
+	if (alignment != 0) {
 		/* It doesn't make sense to have both set */
-		uint32_t mask = alignment - 1;
+		uint32_t mask = (1 << alignment) - 1;
 
 		if (org != -1) {
 			if (org & mask)
 				yyerror("Section \"%s\"'s fixed address doesn't match its alignment",
 					pzName);
-			alignment = 1; /* Ignore it if it's satisfied */
+			alignment = 0; /* Ignore it if it's satisfied */
 		} else if (startaddr[type] & mask) {
 			yyerror("Section \"%s\"'s alignment cannot be attained in %s",
 				pzName, typeNames[type]);
@@ -158,9 +158,9 @@ static struct Section *getSection(char const *pzName, enum SectionType type,
 					fail("Section \"%s\" already declared as fixed at different address $%x",
 					     pSect->pzName, pSect->nOrg);
 				else if (pSect->nAlign != 0
-				      && ((pSect->nAlign - 1) & org))
+				      && (((1 << pSect->nAlign) - 1) & org))
 					fail("Section \"%s\" already declared as aligned to %u bytes",
-					     pSect->pzName, pSect->nAlign);
+					     pSect->pzName, 1 << pSect->nAlign);
 				else
 					/* Otherwise, just override */
 					pSect->nOrg = org;
@@ -214,7 +214,7 @@ static struct Section *getSection(char const *pzName, enum SectionType type,
 					     pSect->pzName);
 				else
 					fail("Section \"%s\" already declared as aligned to %u bytes",
-					     pSect->pzName, pSect->nAlign);
+					     pSect->pzName, 1 << pSect->nAlign);
 			}
 		}
 
@@ -286,7 +286,7 @@ void out_NewSection(char const *pzName, uint32_t type, uint32_t org,
 		fatalerror("Cannot change the section within a `LOAD` block");
 
 	struct Section *pSect = getSection(pzName, type, org, attributes->bank,
-					   1 << attributes->alignment, isUnion);
+					   attributes->alignment, isUnion);
 
 	setSection(pSect);
 	curOffset = isUnion ? 0 : pSect->size;
@@ -305,7 +305,7 @@ void out_SetLoadSection(char const *name, uint32_t type, uint32_t org,
 		fatalerror("`LOAD` blocks cannot be nested");
 
 	struct Section *pSect = getSection(name, type, org, attributes->bank,
-					   1 << attributes->alignment, false);
+					   attributes->alignment, false);
 
 	loadOffset = curOffset;
 	curOffset = 0; /* curOffset -= loadOffset; */
diff --git a/src/link/object.c b/src/link/object.c
index 437aeca2..69043f47 100644
--- a/src/link/object.c
+++ b/src/link/object.c
@@ -279,10 +279,10 @@ static void readSection(FILE *file, struct Section *section,
 		    fileName, section->name);
 	section->isBankFixed = tmp >= 0;
 	section->bank = tmp;
-	tryReadlong(tmp, file, "%s: Cannot read \"%s\"'s alignment: %s",
-		    fileName, section->name);
-	section->isAlignFixed = tmp != 1;
-	section->alignMask = tmp - 1;
+	tryGetc(tmp, file, "%s: Cannot read \"%s\"'s alignment: %s",
+		fileName, section->name);
+	section->isAlignFixed = tmp != 0;
+	section->alignMask = (1 << tmp) - 1;
 
 	if (sect_HasData(section->type)) {
 		/* Ensure we never allocate 0 bytes */
diff --git a/src/rgbds.5 b/src/rgbds.5
index a5479c56..c8af1f3f 100644
--- a/src/rgbds.5
+++ b/src/rgbds.5
@@ -92,8 +92,7 @@ REPT NumberOfSections
                   ; decide (floating bank). This field is only valid for ROMX,
                   ; VRAM, WRAMX and SRAM sections.
 
-    LONG    Align ; Alignment of this section, expressed as 1 << align. 1 if
-                  ; not specified.
+    BYTE    Align ; Alignment of this section, as N bits. 0 when not specified.
 
     IF      (Type == ROMX) || (Type == ROM0) ; Sections that can contain data.