ref: dfb30723819f52a2a9b5aed7ee0c49ad397c2de1
dir: /src/fix/main.c/
/*
* This file is part of RGBDS.
*
* Copyright (c) 2010-2018, Anthony J. Bentley and RGBDS contributors.
*
* SPDX-License-Identifier: MIT
*/
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "extern/err.h"
#include "version.h"
static void print_usage(void)
{
printf(
"usage: rgbfix [-CcjsVv] [-f fix_spec] [-i game_id] [-k licensee_str]\n"
" [-l licensee_id] [-m mbc_type] [-n rom_version] [-p pad_value]\n"
" [-r ram_size] [-t title_str] file\n");
exit(1);
}
int main(int argc, char *argv[])
{
FILE *rom;
int ch;
char *ep;
/*
* Parse command-line options
*/
/* all flags default to false unless options specify otherwise */
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;
bool coloronly = false;
bool nonjapan = false;
bool setlicensee = false;
bool setnewlicensee = false;
bool super = false;
bool setcartridge = false;
bool setramsize = false;
bool resize = false;
bool setversion = false;
char *title; /* game title in ASCII */
char *id; /* game ID in ASCII */
char *newlicensee; /* new licensee ID, two ASCII characters */
int licensee = 0; /* old licensee ID */
int cartridge = 0; /* cartridge hardware ID */
int ramsize = 0; /* RAM size ID */
int version = 0; /* mask ROM version number */
int padvalue = 0; /* to pad the rom with if it changes size */
while ((ch = getopt(argc, argv, "Ccf:i:jk:l:m:n:p:sr:t:Vv")) != -1) {
switch (ch) {
case 'C':
coloronly = true;
/* FALLTHROUGH */
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;
if (strlen(optarg) != 4)
errx(1, "Game ID %s must be exactly 4 characters",
optarg);
id = optarg;
break;
case 'j':
nonjapan = true;
break;
case 'k':
setnewlicensee = true;
if (strlen(optarg) != 2)
errx(1, "New licensee code %s is not the correct length of 2 characters",
optarg);
newlicensee = optarg;
break;
case 'l':
setlicensee = true;
licensee = strtoul(optarg, &ep, 0);
if (optarg[0] == '\0' || *ep != '\0')
errx(1, "Invalid argument for option 'l'");
if (licensee < 0 || licensee > 0xFF)
errx(1, "Argument for option 'l' must be between 0 and 255");
break;
case 'm':
setcartridge = true;
cartridge = strtoul(optarg, &ep, 0);
if (optarg[0] == '\0' || *ep != '\0')
errx(1, "Invalid argument for option 'm'");
if (cartridge < 0 || cartridge > 0xFF)
errx(1, "Argument for option 'm' must be between 0 and 255");
break;
case 'n':
setversion = true;
version = strtoul(optarg, &ep, 0);
if (optarg[0] == '\0' || *ep != '\0')
errx(1, "Invalid argument for option 'n'");
if (version < 0 || version > 0xFF)
errx(1, "Argument for option 'n' must be between 0 and 255");
break;
case 'p':
resize = true;
padvalue = strtoul(optarg, &ep, 0);
if (optarg[0] == '\0' || *ep != '\0')
errx(1, "Invalid argument for option 'p'");
if (padvalue < 0 || padvalue > 0xFF)
errx(1, "Argument for option 'p' must be between 0 and 255");
break;
case 'r':
setramsize = true;
ramsize = strtoul(optarg, &ep, 0);
if (optarg[0] == '\0' || *ep != '\0')
errx(1, "Invalid argument for option 'r'");
if (ramsize < 0 || ramsize > 0xFF)
errx(1, "Argument for option 'r' must be between 0 and 255");
break;
case 's':
super = true;
break;
case 't':
settitle = true;
if (strlen(optarg) > 16)
errx(1, "Title \"%s\" is greater than the maximum of 16 characters",
optarg);
if (strlen(optarg) == 16)
warnx("Title \"%s\" is 16 chars, it is best to keep it to 15 or fewer",
optarg);
title = optarg;
break;
case 'V':
printf("rgbfix %s\n", get_package_version_string());
exit(0);
case 'v':
fixlogo = true;
fixheadsum = true;
fixglobalsum = true;
break;
default:
print_usage();
/* NOTREACHED */
}
}
argc -= optind;
argv += optind;
if (argc == 0)
print_usage();
/*
* Open the ROM file
*/
rom = fopen(argv[argc - 1], "rb+");
if (rom == NULL)
err(1, "Error opening file %s", argv[argc - 1]);
/*
* Read ROM header
*
* Offsets in the buffer are 0x100 less than the equivalent in ROM.
*/
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
* turned on. It must be intact, or the game will not boot.
*/
/*
* See also: global checksums at 0x14D–0x14F, They must
* also be correct for the game to boot, so we fix them
* as well when requested with the -f flag.
*/
uint8_t ninlogo[48] = {
0xCE, 0xED, 0x66, 0x66, 0xCC, 0x0D, 0x00, 0x0B,
0x03, 0x73, 0x00, 0x83, 0x00, 0x0C, 0x00, 0x0D,
0x00, 0x08, 0x11, 0x1F, 0x88, 0x89, 0x00, 0x0E,
0xDC, 0xCC, 0x6E, 0xE6, 0xDD, 0xDD, 0xD9, 0x99,
0xBB, 0xBB, 0x67, 0x63, 0x6E, 0x0E, 0xEC, 0xCC,
0xDD, 0xDC, 0x99, 0x9F, 0xBB, 0xB9, 0x33, 0x3E
};
if (trashlogo) {
for (int i = 0; i < sizeof(ninlogo); i++)
ninlogo[i] = ~ninlogo[i];
}
memcpy(header + 0x04, ninlogo, sizeof(ninlogo));
}
if (settitle) {
/*
* Offset 0x134–0x143: Game Title
* This is a sixteen-character game title in ASCII (no high-
* bit characters).
*/
/*
* See also: CGB flag at 0x143. The sixteenth character of
* the title is co-opted for use as the CGB flag, so they
* may conflict.
*/
/*
* See also: Game ID at 0x13F–0x142. These four ASCII
* characters may conflict with the title.
*/
strncpy((char *)header + 0x34, title, 16);
}
if (setid) {
/*
* Offset 0x13F–0x142: Game ID
* This is a four-character game ID in ASCII (no high-bit
* characters).
*/
memcpy(header + 0x3F, id, 4);
}
if (colorcompatible) {
/*
* Offset 0x143: Game Boy Color Flag
* If bit 7 is set, the ROM has Game Boy Color features.
* If bit 6 is also set, the ROM is for the Game Boy Color
* only. (However, this is not actually enforced by the
* Game Boy.)
*/
/*
* See also: Game Title at 0x134–0x143. The sixteenth
* character of the title overlaps with this flag, so they
* may conflict.
*/
header[0x43] |= 1 << 7;
if (coloronly)
header[0x43] |= 1 << 6;
if (header[0x43] & 0x3F)
warnx("Color flag conflicts with game title");
}
if (setnewlicensee) {
/*
* Offset 0x144–0x145: New Licensee Code
* This is a two-character code identifying which company
* created the game.
*/
/*
* See also: the original Licensee ID at 0x14B.
* This is deprecated and in all newer games is used instead
* as a Super Game Boy flag.
*/
header[0x44] = newlicensee[0];
header[0x45] = newlicensee[1];
}
if (super) {
/*
* Offset 0x146: Super Game Boy Flag
* If not equal to 3, Super Game Boy functions will be
* disabled.
*/
/*
* See also: the original Licensee ID at 0x14B.
* If the Licensee code is not equal to 0x33, Super Game Boy
* functions will be disabled.
*/
if (!setlicensee)
warnx("You should probably set both '-s' and '-l 0x33'");
header[0x46] = 3;
}
if (setcartridge) {
/*
* Offset 0x147: Cartridge Type
* Identifies whether the ROM uses a memory bank controller,
* external RAM, timer, rumble, or battery.
*/
header[0x47] = cartridge;
}
if (resize) {
/*
* Offset 0x148: Cartridge Size
* Identifies the size of the cartridge ROM.
*/
/* We will pad the ROM to match the size given in the header. */
long romsize, newsize;
int headbyte;
uint8_t *buf;
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;
while (romsize > newsize) {
newsize <<= 1;
headbyte++;
}
if (newsize > 0x800000) /* ROM is bigger than 8MiB */
warnx("ROM size is bigger than 8MiB");
buf = malloc(newsize - romsize);
if (buf == NULL)
errx(1, "Couldn't allocate memory for padded ROM.");
memset(buf, padvalue, newsize - romsize);
if (fwrite(buf, 1, newsize - romsize, rom) != newsize - romsize)
err(1, "Could not pad ROM file");
header[0x48] = headbyte;
free(buf);
}
if (setramsize) {
/*
* Offset 0x149: RAM Size
*/
header[0x49] = ramsize;
}
if (nonjapan) {
/*
* Offset 0x14A: Non-Japanese Region Flag
*/
header[0x4A] = 1;
}
if (setlicensee) {
/*
* Offset 0x14B: Licensee Code
* This identifies which company created the game.
*
* This byte is deprecated and should be set to 0x33 in new
* releases.
*/
/*
* See also: the New Licensee ID at 0x144–0x145.
*/
header[0x4B] = licensee;
}
if (setversion) {
/*
* Offset 0x14C: Mask ROM Version Number
* Which version of the ROM this is.
*/
header[0x4C] = version;
}
if (fixheadsum || trashheadsum) {
/*
* Offset 0x14D: Header Checksum
*/
uint8_t headcksum = 0;
for (int i = 0x34; i < 0x4D; ++i)
headcksum = headcksum - header[i] - 1;
if (trashheadsum)
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;
if (fseek(rom, 0, SEEK_SET) != 0)
err(1, "Could not start calculating global checksum");
int i = 0;
int byte;
while ((byte = fgetc(rom)) != EOF) {
if (i != 0x14E && i != 0x14F)
globalcksum += byte;
i++;
}
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");
}
if (fclose(rom) != 0)
err(1, "Could not complete ROM write");
return 0;
}