shithub: rgbds

--- a/include/link/mylink.h

+++ b/include/link/mylink.h

@@ -10,6 +10,7 @@

 extern SLONG options;

 #define OPT_SMALL	0x01

 #define OPT_SMART_C_LINK	0x02

+#define OPT_OVERLAY	0x04

 enum eRpnData {

 	RPN_ADD = 0,

--- a/include/link/output.h

+++ b/include/link/output.h

@@ -2,6 +2,7 @@

 #define	RGBDS_LINK_OUTPUT_H

 void out_Setname(char *tzOutputfile);

+void out_SetOverlayname(char *tzOverlayfile);

 void Output(void);

 #endif

--- a/src/link/assign.c

+++ b/src/link/assign.c

@@ -258,7 +258,7 @@

 AssignFloatingBankSections(enum eSectionType type)

 	ensureSectionTypeIsValid(type);

 	struct sSection *pSection;

 	while ((pSection = FindLargestSection(type, false))) {

@@ -265,6 +265,9 @@

 		SLONG org;

 		if ((org = area_AllocAnyBank(pSection->nByteSize, pSection->nAlign, type)) != -1) {

+			if (options & OPT_OVERLAY) {

+				errx(1, "All sections must be fixed when using overlay");

+			}

 			pSection->nOrg = org & 0xFFFF;

 			pSection->nBank = org >> 16;

 			pSection->oAssigned = 1;

@@ -421,6 +424,9 @@

 	while (pSection) {

 		if (pSection->oAssigned == 0

 			&& pSection->nOrg != -1 && pSection->nBank == -1) {

+			if (options & OPT_OVERLAY) {

+				errx(1, "All sections must be fixed when using overlay");

+			}

 			switch (pSection->Type) {

 			case SECT_ROMX:

 			case SECT_VRAM:

--- a/src/link/main.c

+++ b/src/link/main.c

@@ -35,8 +35,8 @@

 usage(void)

 	printf(

-"usage: rgblink [-t] [-m mapfile] [-n symfile] [-o outfile] [-p pad_value]\n"

-"               [-s symbol] file [...]\n");

+"usage: rgblink [-t] [-m mapfile] [-n symfile] [-O overlay] [-o outfile] \n"

+"               [-p pad_value] [-s symbol] file [...]\n");

 	exit(1);

@@ -56,7 +56,7 @@

 	progname = argv[0];

-	while ((ch = getopt(argc, argv, "m:n:o:p:s:t")) != -1) {

+	while ((ch = getopt(argc, argv, "m:n:o:O:p:s:t")) != -1) {

 		switch (ch) {

 		case 'm':

 			SetMapfileName(optarg);

@@ -66,6 +66,10 @@

 			break;

 		case 'o':

 			out_Setname(optarg);

+			break;

+		case 'O':

+			out_SetOverlayname(optarg);

+			options |= OPT_OVERLAY;

 			break;

 		case 'p':

 			fillchar = strtoul(optarg, &ep, 0);

--- a/src/link/output.c

+++ b/src/link/output.c

@@ -8,9 +8,12 @@

 #include "link/assign.h"

 char *tzOutname;

+char *tzOverlayname = NULL;

+SLONG MaxOverlayBank;

 void

-writehome(FILE * f)

+writehome(FILE * f, FILE * f_overlay)

 	struct sSection *pSect;

 	UBYTE *mem;

@@ -18,8 +21,13 @@

 	mem = malloc(MaxAvail[BANK_ROM0]);

 	if (!mem)

 		return;

-	memset(mem, fillchar, MaxAvail[BANK_ROM0]);

+	if (f_overlay != NULL) {

+		fseek(f_overlay, 0L, SEEK_SET);

+		fread(mem, 1, MaxAvail[BANK_ROM0], f_overlay);

+	} else {

+		memset(mem, fillchar, MaxAvail[BANK_ROM0]);

+	}

 	MapfileInitBank(0);

 	pSect = pSections;

@@ -26,7 +34,7 @@

 	while (pSect) {

 		if (pSect->Type == SECT_ROM0) {

 			memcpy(mem + pSect->nOrg, pSect->pData,

-			    pSect->nByteSize);

+				pSect->nByteSize);

 			MapfileWriteSection(pSect);

 		pSect = pSect->pNext;

@@ -39,7 +47,7 @@

 void

-writebank(FILE * f, SLONG bank)

+writebank(FILE * f, FILE * f_overlay, SLONG bank)

 	struct sSection *pSect;

 	UBYTE *mem;

@@ -48,7 +56,12 @@

 	if (!mem)

 		return;

-	memset(mem, fillchar, MaxAvail[bank]);

+	if (f_overlay != NULL && bank <= MaxOverlayBank) {

+		fseek(f_overlay, bank*0x4000, SEEK_SET);

+		fread(mem, 1, MaxAvail[bank], f_overlay);

+	} else {

+		memset(mem, fillchar, MaxAvail[bank]);

+	}

 	MapfileInitBank(bank);

 	pSect = pSections;

@@ -55,7 +68,7 @@

 	while (pSect) {

 		if (pSect->Type == SECT_ROMX && pSect->nBank == bank) {

 			memcpy(mem + pSect->nOrg - 0x4000, pSect->pData,

-			    pSect->nByteSize);

+				pSect->nByteSize);

 			MapfileWriteSection(pSect);

 		pSect = pSect->pNext;

@@ -74,17 +87,51 @@

 void

+out_SetOverlayname(char *tzOverlayfile)

+{

+	tzOverlayname = tzOverlayfile;

+}

+void

 Output(void)

 	SLONG i;

 	FILE *f;

+	FILE *f_overlay = NULL;

 	if ((f = fopen(tzOutname, "wb"))) {

-		writehome(f);

+		if (tzOverlayname) {

+			f_overlay = fopen(tzOverlayname, "rb");

+			if (!f_overlay) {

+				fprintf(stderr, "Failed to open overlay file %s\n", tzOverlayname);

+				exit(1);

+			}

+			fseek(f_overlay, 0, SEEK_END);

+			if (ftell(f_overlay) % 0x4000 != 0) {

+				fprintf(stderr, "Overlay file must be aligned to 0x4000 bytes\n");

+				exit(1);

+			}

+			MaxOverlayBank = (ftell(f_overlay) / 0x4000) - 1;

+			if (MaxOverlayBank < 1) {

+				fprintf(stderr, "Overlay file be at least 0x8000 bytes\n");

+				exit(1);

+			}

+			if (MaxOverlayBank > MaxBankUsed) {

+				MaxBankUsed = MaxOverlayBank;

+			}

+		}

+		writehome(f, f_overlay);

 		for (i = 1; i <= MaxBankUsed; i += 1)

-			writebank(f, i);

+			writebank(f, f_overlay, i);

 		fclose(f);

+		if (tzOverlayname) {

+			fclose(f_overlay);

+		}

 	for (i = BANK_WRAM0; i < MAXBANKS; i++) {

 		struct sSection *pSect;

--- a/src/link/rgblink.1

+++ b/src/link/rgblink.1

@@ -9,6 +9,7 @@

 .Op Fl t

 .Op Fl m Ar mapfile

 .Op Fl n Ar symfile

+.Op Fl O Ar overlayfile

 .Op Fl o Ar outfile

 .Op Fl p Ar pad_value

 .Op Fl s Ar symbol

@@ -32,6 +33,10 @@

 Write a mapfile to the given filename.

 .It Fl n Ar symfile

 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.

 .It Fl o Ar outfile

 Write ROM image to the given filename.

 .It Fl p Ar pad_value