bryc / rare-n64-chksm Goto Github PK

void gamefileGenerateCRC(u8 *addressA, u8 *addressB, save_data *retval)
{
    u8 *byte;
    s32 shift      = 0; // Shift value
    s64 polynormal = 0x8F809F473108B3C1;
    s32 checksum1  = 0; // Final checksum #1
    s32 checksum2  = 0; // Final checksum #2

    for(byte = addressA; byte < addressB; byte++,shift += 7)
    {
        polynormal += *byte << (shift & 0xF) ;
        checksum1 ^= randomGetNextFrom(&polynormal);
    }

    for(byte = addressB - 1; byte >= addressA; byte--,shift += 3)
    {
        polynormal += *byte << (shift & 0xF) ;
        checksum2 ^= randomGetNextFrom(&polynormal);
    }
    retval->chksum1 = checksum1;
    retval->chksum2 = checksum2;
}

void sub_GAME_7F01D7A0(save_data *save)
{
    if (save >= &saves[0] && save < &saves[5])
    {
        if (gamefileGamePakProbe() != 0)
        {
            gamefileGenerateCRC(&save->completion_bitflags, save + 1, save);
            joyGamePakLongWrite((((u32)((save - &saves[0]) * 0x60) >> 3) + 4), save, sizeof(save_data));
        }
    }
}

typedef struct save_data
{
  s32 chksum1;
  s32 chksum2;
  u8 completion_bitflags;
  u8 flag_007;
  u8 music_vol;
  u8 sfx_vol;
  u16 options;
  u8 unlocked_cheats_1;
  u8 unlocked_cheats_2;
  u8 unlocked_cheats_3;
  char padding;
  u8 times[(SP_LEVEL_MAX-1) * 4];
} save_data;