Make it possible to disable emitting nop after halt.

src/asm/gameboy/yaccprt4.y

@@ -153,8 +153,13 @@ z80_ex			:	T_Z80_EX T_MODE_HL comma T_MODE_SP_IND
 					{ out_AbsByte(0xE3); }
 ;
 
-z80_halt		:	T_Z80_HALT
+z80_halt: T_Z80_HALT
-					{ out_AbsByte(0x76); out_AbsByte(0x00); }
+		{
+			out_AbsByte(0x76);
+			if (haltnop) {
+				out_AbsByte(0x00);
+			}
+		}
 ;
 
 z80_inc			:	T_Z80_INC reg_r

src/asm/main.c

@@ -8,6 +8,7 @@
 #include <math.h>
 #include <getopt.h>
 #include <stdarg.h>
+#include <stdbool.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -29,6 +30,8 @@ void setuplex(void);
  *
  */
 
+bool haltnop;
+
 clock_t nStartClock, nEndClock;
 SLONG nLineNo;
 ULONG nTotalLines, nPass, nPC, nIFDepth, nErrors;
@@ -238,7 +241,8 @@ PrintUsage(void)
 {
 	printf("RGBAsm v" ASM_VERSION " (part of ASMotor " ASMOTOR_VERSION
 	    ")\n\n");
-	printf("Usage: rgbasm [-b chars] [-g chars] [-i path] [-o outfile] [-p pad_value] file\n");
+	printf("Usage: rgbasm [-h] [-b chars] [-g chars] [-i path] [-o outfile] [-p pad_value]\n"
+	    "              file\n");
 	exit(1);
 }
 /*
@@ -258,6 +262,8 @@ main(int argc, char *argv[])
 
 	char *tzMainfile;
 
+	haltnop = true;
+
 	if (argc == 1)
 		PrintUsage();
 
@@ -275,7 +281,7 @@ main(int argc, char *argv[])
 
 	newopt = CurrentOptions;
 
-	while ((ch = getopt(argc, argv, "b:g:i:o:p:")) != -1) {
+	while ((ch = getopt(argc, argv, "b:g:hi:o:p:")) != -1) {
 		switch (ch) {
 		case 'b':
 			if (strlen(optarg) == 2) {
@@ -299,6 +305,9 @@ main(int argc, char *argv[])
 				exit(1);
 			}
 			break;
+		case 'h':
+			haltnop = false;
+			break;
 		case 'i':
 			fstk_AddIncludePath(optarg);
 			break;

src/asm/rgbasm.1

@@ -6,6 +6,7 @@
 .Nd Game Boy assembler
 .Sh SYNOPSIS
 .Nm rgbasm
+.Op Fl h
 .Op Fl b Ar chars
 .Op Fl g Ar chars
 .Op Fl i Ar path
@@ -24,6 +25,17 @@ The defaults are 01.
 .It Fl g Ar chars
 Change the four characters used for binary constants.
 The defaults are 0123.
+.It Fl h
+By default,
+.Nm
+inserts a
+.Sq nop
+instruction immediately after any
+.Sq halt
+instruction.
+The
+.Fl h
+option disables this behavior.
 .It Fl i Ar path
 Add an include path.
 .It Fl o Ar outfile

src/asm/yaccprt1.y

@@ -1,6 +1,7 @@
 %{
 #include <ctype.h>
 #include <errno.h>
+#include <stdbool.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -15,6 +16,8 @@
 #include "asm/main.h"
 #include "asm/lexer.h"
 
+extern bool haltnop;
+
 char	*tzNewMacro;
 ULONG	ulNewMacroSize;