ref: b9f92536a9bce4a28e61a9a0e011d316e001ec34
dir: /src/fix/main.c/
/*
* Copyright © 2010 Anthony J. Bentley <[email protected]>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include <err.h>
#include <limits.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
static void
usage(void)
{
printf("usage: rgbfix [-Ccjsv] [-k licensee_str] [-l licensee_id] "
"[-m mbc_type]\n" " [-n rom_version] [-p pad_value] "
"[-r ram_size] [-t title_str] file.gb\n");
}
int
main(int argc, char *argv[])
{
FILE *rom;
int ch;
char *ep;
/*
* Open the ROM file
*/
if (argc < 2)
usage();
if ((rom = fopen(argv[argc - 1], "rb+")) == NULL)
err(1, "Error opening file %s", argv[argc - 1]);
/*
* Parse command-line options
*/
/* all flags default to false unless options specify otherwise */
bool validate = false;
bool settitle = 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 = NULL; /* game title in ASCII */
char *newlicensee = NULL; /* new licensee ID, two ASCII characters */
int licensee = -1; /* old licensee ID */
int cartridge = -1; /* cartridge hardware ID */
int ramsize = -1; /* RAM size ID */
int version = -1; /* mask ROM version number */
int padvalue = -1; /* to pad the rom with if it changes size */
while ((ch = getopt(argc, argv, "Ccjk:l:m:n:p:sr:t:v")) != -1) {
switch (ch) {
case 'C':
coloronly = true;
/* FALLTHROUGH */
case 'c':
colorcompatible = true;
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':
validate = true;
break;
default:
usage();
/* NOTREACHED */
}
}
argc -= optind;
argv += optind;
/*
* Write changes to ROM
*/
if (validate) {
/*
* 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 the -v flag is set.
*/
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
};
fseek(rom, 0x104, SEEK_SET);
fwrite(ninlogo, 1, 48, rom);
}
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.
*/
fseek(rom, 0x134, SEEK_SET);
fwrite(title, 1, strlen(title) + 1, rom);
while (ftell(rom) < 0x143)
fputc(0, rom);
}
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.
*/
uint8_t byte;
fseek(rom, 0x143, SEEK_SET);
byte = fgetc(rom);
byte |= 1 << 7;
if (coloronly)
byte |= 1 << 6;
if (byte & 0x3F)
warnx("Color flag conflicts with game title");
fseek(rom, 0x143, SEEK_SET);
fputc(byte, rom);
}
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.
*/
fseek(rom, 0x144, SEEK_SET);
fwrite(newlicensee, 1, 2, rom);
}
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'");
fseek(rom, 0x146, SEEK_SET);
fputc(3, rom);
}
if (setcartridge) {
/*
* Offset 0x147: Cartridge Type
* Identifies whether the ROM uses a memory bank controller,
* external RAM, timer, rumble, or battery.
*/
fseek(rom, 0x147, SEEK_SET);
fputc(cartridge, rom);
}
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. */
int romsize, newsize, headbyte;
fseek(rom, 0, SEEK_END);
romsize = ftell(rom);
newsize = 0x8000;
headbyte = 0;
while (romsize > newsize) {
newsize <<= 1;
headbyte++;
}
while (newsize != ftell(rom)) /* ROM needs resizing */
fputc(padvalue, rom);
if (newsize > 0x800000) /* ROM is bigger than 8MiB */
warnx("ROM size is bigger than 8MiB");
fseek(rom, 0x148, SEEK_SET);
fputc(headbyte, rom);
}
if (setramsize) {
/*
* Offset 0x149: RAM Size
*/
fseek(rom, 0x149, SEEK_SET);
fputc(ramsize, rom);
}
if (nonjapan) {
/*
* Offset 0x14A: Non-Japanese Region Flag
*/
fseek(rom, 0x14A, SEEK_SET);
fputc(1, rom);
}
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.
*/
fseek(rom, 0x14B, SEEK_SET);
fputc(licensee, rom);
}
if (setversion) {
/*
* Offset 0x14C: Mask ROM Version Number
* Which version of the ROM this is.
*/
fseek(rom, 0x14C, SEEK_SET);
fputc(version, rom);
}
if (validate) {
/*
* Offset 0x14D: Header Checksum
*/
uint8_t headcksum;
headcksum = 0;
fseek(rom, 0x134, SEEK_SET);
for (int i = 0; i < (0x14D - 0x134); ++i)
headcksum = headcksum - fgetc(rom) - 1;
fseek(rom, 0x14D, SEEK_SET);
fputc(headcksum, rom);
/*
* Offset 0x14E–0x14F: Global Checksum
*/
uint16_t globalcksum;
globalcksum = 0;
rewind(rom);
for (int i = 0; i < 0x14E; ++i)
globalcksum += fgetc(rom);
int byte;
fseek(rom, 0x150, SEEK_SET);
while ((byte = fgetc(rom)) != EOF)
globalcksum += byte;
fseek(rom, 0x14E, SEEK_SET);
fputc(globalcksum >> 8, rom);
fputc(globalcksum & 0xFF, rom);
}
fclose(rom);
return 0;
}