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Add a new flag, -f, which allows independently fixing or trashing checksums.

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This commit is contained in:
Anthony J. Bentley
2018-03-10 21:48:23 -07:00
parent f86dbafad0
commit 5a4bbe4985
2 changed files with 63 additions and 15 deletions
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45
src/fix/main.c
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@@ -20,9 +20,9 @@
static void print_usage(void)
{
printf(
"usage: rgbfix [-CcjsVv] [-i game_id] [-k licensee_str] [-l licensee_id]\n"
" [-m mbc_type] [-n rom_version] [-p pad_value] [-r ram_size]\n"
" [-t title_str] file\n");
"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);
}
@@ -37,7 +37,12 @@ int main(int argc, char *argv[])
*/
/* all flags default to false unless options specify otherwise */
bool validate = false;
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;
@@ -61,7 +66,7 @@ int main(int argc, char *argv[])
int version = 0; /* mask ROM version number */
int padvalue = 0; /* to pad the rom with if it changes size */
while ((ch = getopt(argc, argv, "Cci:jk:l:m:n:p:sr:t:Vv")) != -1) {
while ((ch = getopt(argc, argv, "Ccf:i:jk:l:m:n:p:sr:t:Vv")) != -1) {
switch (ch) {
case 'C':
coloronly = true;
@@ -69,6 +74,14 @@ int main(int argc, char *argv[])
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;
@@ -168,7 +181,9 @@ int main(int argc, char *argv[])
printf("rgbfix %s\n", get_package_version_string());
exit(0);
case 'v':
validate = true;
fixlogo = true;
fixheadsum = true;
fixglobalsum = true;
break;
default:
print_usage();
@@ -195,7 +210,7 @@ int main(int argc, char *argv[])
* Write changes to ROM
*/
if (validate) {
if (fixlogo || trashlogo) {
/*
* Offset 0x104–0x133: Nintendo Logo
* This is a bitmap image that displays when the Game Boy is
@@ -205,7 +220,7 @@ int main(int argc, char *argv[])
/*
* 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.
* as well when requested with the -f flag.
*/
uint8_t ninlogo[48] = {
@@ -217,6 +232,10 @@ int main(int argc, char *argv[])
0xDD, 0xDC, 0x99, 0x9F, 0xBB, 0xB9, 0x33, 0x3E
};
if (trashlogo)
for (int i = 0; i < sizeof(ninlogo); i++)
ninlogo[i] = ~ninlogo[i];
fseek(rom, 0x104, SEEK_SET);
fwrite(ninlogo, 1, 48, rom);
}
@@ -415,7 +434,7 @@ int main(int argc, char *argv[])
fputc(version, rom);
}
if (validate) {
if (fixheadsum || trashheadsum) {
/*
* Offset 0x14D: Header Checksum
*/
@@ -426,9 +445,14 @@ int main(int argc, char *argv[])
for (int i = 0; i < (0x14D - 0x134); ++i)
headcksum = headcksum - fgetc(rom) - 1;
if (trashheadsum)
headcksum = ~headcksum;
fseek(rom, 0x14D, SEEK_SET);
fputc(headcksum, rom);
}
if (fixglobalsum || trashglobalsum) {
/*
* Offset 0x14E–0x14F: Global Checksum
*/
@@ -445,6 +469,9 @@ int main(int argc, char *argv[])
while ((byte = fgetc(rom)) != EOF)
globalcksum += byte;
if (trashglobalsum)
globalcksum = ~globalcksum;
fseek(rom, 0x14E, SEEK_SET);
fputc(globalcksum >> 8, rom);
fputc(globalcksum & 0xFF, rom);