The-Homebrew-Cloud/Genesis-Plus-GX
2
0
Fork 0
mirror of https://github.com/ekeeke/Genesis-Plus-GX.git synced 2024-12-27 19:51:48 +01:00
Code Issues Packages Projects Releases Wiki Activity

Add support for short GG cheats.

Browse Source
This commit is contained in:
iLag 2017-03-25 20:04:04 -07:00
parent 929d8bd723
commit 0ac5889f81
1 changed files with 26 additions and 22 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

30
libretro/libretro.c
View File

@ -1265,7 +1265,7 @@ static uint32_t decode_cheat(char *string, int index)
//If System is Master-based
//Game Genie
if ((strlen(string) >=11) && (string[3] == '-') && (string[7] == '-'))
if ((strlen(string) >=7) && (string[3] == '-'))
{
/* decode 8-bit data */
for (i=0; i<2; i++)
@ -1290,13 +1290,9 @@ static uint32_t decode_cheat(char *string, int index)
n = (p - arvalidchars) & 0xF;
n ^= 0xF; /* bits inversion */
address |= (n << 12);
/* RAM address are also supported */
if (address >= 0xC000)
/* Optional: decode reference 8-bit data */
if (*string=='-')
{
/* convert to 24-bit Work RAM address */
address = 0xFF0000 | (address & 0x1FFF);
}
/* decode reference 8-bit data */
for (i=0; i<2; i++)
{
string++; /* skip separator and 2nd digit */
@ -1307,11 +1303,15 @@ static uint32_t decode_cheat(char *string, int index)
}
ref = (ref >> 2) | ((ref & 0x03) << 6); /* 2-bit right rotation */
ref ^= 0xBA; /* XOR */
/* update old data value */
cheatlist[index].old = ref;
/* code length */
len = 11;
}
else
{
/* code length */
len = 7;
}
}
//Action Replay
else if ((strlen(string) >=9) && (string[4] == '-')){
@ -1389,11 +1389,14 @@ static uint32_t decode_cheat(char *string, int index)
n = (p - arvalidchars) & 0xF;
data |= (n << ((1 - i) * 4));
}
/* update old data value */
cheatlist[index].old = ref;
/* code length */
len = 9;
}
/* convert to 24-bit Work RAM address */
if (address >= 0xC000)
{
address = 0xFF0000 | (address & 0x1FFF);
}
}
/* Valid code found ? */
if (len)
@ -1401,6 +1404,7 @@ static uint32_t decode_cheat(char *string, int index)
/* update cheat address & data values */
cheatlist[index].address = address;
cheatlist[index].data = data;
cheatlist[index].old = ref;
}
/* return code length (0 = invalid) */
return len;
@ -1544,8 +1548,8 @@ void ROMCheatUpdate(void)
/* get current banked ROM address */
ptr = &z80_readmap[(cheatlist[index].address) >> 10][cheatlist[index].address & 0x03FF];
/* check if reference matches original ROM data */
if (((uint8_t)cheatlist[index].old) == *ptr)
/* check if reference exists and matches original ROM data */
if (!cheatlist[index].old || ((uint8_t)cheatlist[index].old) == *ptr)
{
/* patch data */
*ptr = cheatlist[index].data;