diff options
| -rw-r--r-- | src/snesout.c | 23 |
1 files changed, 22 insertions, 1 deletions
diff --git a/src/snesout.c b/src/snesout.c index 1612a6b..911ee49 100644 --- a/src/snesout.c +++ b/src/snesout.c @@ -133,6 +133,16 @@ static int PokeS(Byte *mem, int addr, const char *str, int maxlen, char pad) return addr; } +static unsigned CalcChecksum(Byte *p, int len, unsigned csum) +{ + while(len-- > 0) + { + csum += *p++; + } + + return csum & 0xffff; +} + /* ---------------------------------------- INTERFACES */ @@ -198,6 +208,7 @@ int SNESOutput(const char *filename, const char *filename_bank, int base; int len; int f; + unsigned csum; /* If the ROM type is LOROM then we assume each bank holds 32Kb. Otherwise each bank is a full 64Kb. @@ -275,7 +286,17 @@ int SNESOutput(const char *filename, const char *filename_bank, PokeB(mem, 0xffd8, option.ram_size); - /* TODO: Need checksums? */ + /* Calculate checksum + */ + csum = 0; + + for(f = 0; f < count; f++) + { + csum = CalcChecksum(bank[f]->memory + base, len, csum); + } + + PokeW(mem, 0xffde, csum); + PokeW(mem, 0xffdc, 0xffffu - csum); /* Output ROM contents */ |