Implement cheatcode support - implement retro_cheat_reset/retro_cheat_set

This commit is contained in:
twinaphex 2014-12-06 16:27:19 +01:00
parent 41c1f4fe70
commit 8b4b807b8c

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@ -81,6 +81,32 @@ static retro_input_state_t input_state_cb;
static retro_environment_t environ_cb; static retro_environment_t environ_cb;
static retro_audio_sample_batch_t audio_cb; static retro_audio_sample_batch_t audio_cb;
/* Cheat Support */
#define MAX_CHEATS (150)
#define MAX_DESC_LENGTH (63)
typedef struct
{
char code[12];
char text[MAX_DESC_LENGTH];
uint8_t enable;
uint16_t data;
uint16_t old;
uint32_t address;
uint8_t *prev;
} CHEATENTRY;
static int maxcheats = 0;
static int maxROMcheats = 0;
static int maxRAMcheats = 0;
static CHEATENTRY cheatlist[MAX_CHEATS];
static uint8_t cheatIndexes[MAX_CHEATS];
static char ggvalidchars[] = "ABCDEFGHJKLMNPRSTVWXYZ0123456789";
static char arvalidchars[] = "0123456789ABCDEF";
/************************************ /************************************
* Genesis Plus GX implementation * Genesis Plus GX implementation
************************************/ ************************************/
@ -169,6 +195,8 @@ int load_archive(char *filename, unsigned char *buffer, int maxsize, char *exten
return size; return size;
} }
void RAMCheatUpdate(void);
void osd_input_update(void) void osd_input_update(void)
{ {
int i, player = 0; int i, player = 0;
@ -176,6 +204,9 @@ void osd_input_update(void)
input_poll_cb(); input_poll_cb();
/* Update RAM patches */
RAMCheatUpdate();
for (i = 0; i < MAX_INPUTS; i++) for (i = 0; i < MAX_INPUTS; i++)
{ {
temp = 0; temp = 0;
@ -941,6 +972,314 @@ static void check_variables(void)
} }
} }
/* Cheat Support */
static uint32_t decode_cheat(char *string, int index)
{
char *p;
int i,n;
uint32_t len = 0;
uint32_t address = 0;
uint16_t data = 0;
uint8_t ref = 0;
/* 16-bit Game Genie code (ABCD-EFGH) */
if ((strlen(string) >= 9) && (string[4] == '-'))
{
/* 16-bit system only */
if ((system_hw & SYSTEM_PBC) != SYSTEM_MD)
{
return 0;
}
for (i = 0; i < 8; i++)
{
if (i == 4) string++;
p = strchr (ggvalidchars, *string++);
if (p == NULL) return 0;
n = p - ggvalidchars;
switch (i)
{
case 0:
data |= n << 3;
break;
case 1:
data |= n >> 2;
address |= (n & 3) << 14;
break;
case 2:
address |= n << 9;
break;
case 3:
address |= (n & 0xF) << 20 | (n >> 4) << 8;
break;
case 4:
data |= (n & 1) << 12;
address |= (n >> 1) << 16;
break;
case 5:
data |= (n & 1) << 15 | (n >> 1) << 8;
break;
case 6:
data |= (n >> 3) << 13;
address |= (n & 7) << 5;
break;
case 7:
address |= n;
break;
}
}
/* code length */
len = 9;
}
/* 8-bit Game Genie code (DDA-AAA-XXX) */
else if ((strlen(string) >= 11) && (string[3] == '-') && (string[7] == '-'))
{
/* 8-bit system only */
if ((system_hw & SYSTEM_PBC) == SYSTEM_MD)
{
return 0;
}
/* decode 8-bit data */
for (i=0; i<2; i++)
{
p = strchr (arvalidchars, *string++);
if (p == NULL) return 0;
n = (p - arvalidchars) & 0xF;
data |= (n << ((1 - i) * 4));
}
/* decode 16-bit address (low 12-bits) */
for (i=0; i<3; i++)
{
if (i==1) string++; /* skip separator */
p = strchr (arvalidchars, *string++);
if (p == NULL) return 0;
n = (p - arvalidchars) & 0xF;
address |= (n << ((2 - i) * 4));
}
/* decode 16-bit address (high 4-bits) */
p = strchr (arvalidchars, *string++);
if (p == NULL) return 0;
n = (p - arvalidchars) & 0xF;
n ^= 0xF; /* bits inversion */
address |= (n << 12);
/* RAM address are also supported */
if (address >= 0xC000)
{
/* 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 */
p = strchr (arvalidchars, *string++);
if (p == NULL) return 0;
n = (p - arvalidchars) & 0xF;
ref |= (n << ((1 - i) * 4));
}
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;
}
/* Action Replay code */
else if (string[6] == ':')
{
if ((system_hw & SYSTEM_PBC) == SYSTEM_MD)
{
/* 16-bit code (AAAAAA:DDDD) */
if (strlen(string) < 11) return 0;
/* decode 24-bit address */
for (i=0; i<6; i++)
{
p = strchr (arvalidchars, *string++);
if (p == NULL) return 0;
n = (p - arvalidchars) & 0xF;
address |= (n << ((5 - i) * 4));
}
/* decode 16-bit data */
string++;
for (i=0; i<4; i++)
{
p = strchr (arvalidchars, *string++);
if (p == NULL) return 0;
n = (p - arvalidchars) & 0xF;
data |= (n << ((3 - i) * 4));
}
/* code length */
len = 11;
}
else
{
/* 8-bit code (xxAAAA:DD) */
if (strlen(string) < 9) return 0;
/* decode 16-bit address */
string+=2;
for (i=0; i<4; i++)
{
p = strchr (arvalidchars, *string++);
if (p == NULL) return 0;
n = (p - arvalidchars) & 0xF;
address |= (n << ((3 - i) * 4));
}
/* ROM addresses are not supported */
if (address < 0xC000) return 0;
/* convert to 24-bit Work RAM address */
address = 0xFF0000 | (address & 0x1FFF);
/* decode 8-bit data */
string++;
for (i=0; i<2; i++)
{
p = strchr (arvalidchars, *string++);
if (p == NULL) return 0;
n = (p - arvalidchars) & 0xF;
data |= (n << ((1 - i) * 4));
}
/* code length */
len = 9;
}
}
/* Valid code found ? */
if (len)
{
/* update cheat address & data values */
cheatlist[index].address = address;
cheatlist[index].data = data;
cheatlist[index].enable = 1; // Enable the cheat by default
}
/* return code length (0 = invalid) */
return len;
}
static void apply_cheats(void)
{
uint8_t *ptr;
/* clear ROM&RAM patches counter */
maxROMcheats = maxRAMcheats = 0;
int i;
for (i = 0; i < maxcheats; i++)
{
if (cheatlist[i].enable)
{
if (cheatlist[i].address < cart.romsize)
{
if ((system_hw & SYSTEM_PBC) == SYSTEM_MD)
{
/* patch ROM data */
cheatlist[i].old = *(uint16_t *)(cart.rom + (cheatlist[i].address & 0xFFFFFE));
*(uint16_t *)(cart.rom + (cheatlist[i].address & 0xFFFFFE)) = cheatlist[i].data;
}
else
{
/* add ROM patch */
maxROMcheats++;
cheatIndexes[MAX_CHEATS - maxROMcheats] = i;
/* get current banked ROM address */
ptr = &z80_readmap[(cheatlist[i].address) >> 10][cheatlist[i].address & 0x03FF];
/* check if reference matches original ROM data */
if (((uint8_t)cheatlist[i].old) == *ptr)
{
/* patch data */
*ptr = cheatlist[i].data;
/* save patched ROM address */
cheatlist[i].prev = ptr;
}
else
{
/* no patched ROM address yet */
cheatlist[i].prev = NULL;
}
}
}
else if (cheatlist[i].address >= 0xFF0000)
{
/* add RAM patch */
cheatIndexes[maxRAMcheats++] = i;
}
}
}
}
static void clear_cheats(void)
{
int i = maxcheats;
/* disable cheats in reversed order in case the same address is used by multiple patches */
while (i > 0)
{
if (cheatlist[i-1].enable)
{
if (cheatlist[i-1].address < cart.romsize)
{
if ((system_hw & SYSTEM_PBC) == SYSTEM_MD)
{
/* restore original ROM data */
*(uint16_t *)(cart.rom + (cheatlist[i-1].address & 0xFFFFFE)) = cheatlist[i-1].old;
}
else
{
/* check if previous banked ROM address has been patched */
if (cheatlist[i-1].prev != NULL)
{
/* restore original data */
*cheatlist[i-1].prev = cheatlist[i-1].old;
/* no more patched ROM address */
cheatlist[i-1].prev = NULL;
}
}
}
}
i--;
}
}
static void remove_cheats(void)
{
int i = maxcheats;
while (i > 0)
{
if (cheatlist[i-1].enable)
{
cheatlist[i-1].text[0] = 0;
cheatlist[i-1].code[0] = 0;
cheatlist[i-1].address = 0;
cheatlist[i-1].data = 0;
cheatlist[i-1].enable = 0;
maxcheats--;
}
i--;
}
}
/****************************************************************************
* RAMCheatUpdate
*
* Apply RAM patches (this should be called once per frame)
*
****************************************************************************/
void RAMCheatUpdate(void)
{
int index, cnt = maxRAMcheats;
while (cnt)
{
/* get cheat index */
index = cheatIndexes[--cnt];
/* apply RAM patch */
//if (cheatlist[index].data & 0xFF00)
if (cheatlist[index].data & 0x00FF) // For LSB?
{
/* word patch */
*(uint16_t *)(work_ram + (cheatlist[index].address & 0xFFFE)) = cheatlist[index].data;
}
else
{
/* byte patch */
work_ram[cheatlist[index].address & 0xFFFF] = cheatlist[index].data;
}
}
}
/************************************ /************************************
* libretro implementation * libretro implementation
************************************/ ************************************/
@ -1173,12 +1512,24 @@ bool retro_unserialize(const void *data, size_t size)
return TRUE; return TRUE;
} }
void retro_cheat_reset(void) {} void retro_cheat_reset(void)
{
/* clear existing ROM patches */
clear_cheats();
/* remove cheats from the list */
remove_cheats();
}
void retro_cheat_set(unsigned index, bool enabled, const char *code) void retro_cheat_set(unsigned index, bool enabled, const char *code)
{ {
(void)index; /* clear existing ROM patches */
(void)enabled; clear_cheats();
(void)code; /* interpret code and give it an index */
decode_cheat((char *)code, maxcheats);
/* increment cheat count */
maxcheats++;
/* apply ROM patches */
apply_cheats();
} }
bool retro_load_game(const struct retro_game_info *info) bool retro_load_game(const struct retro_game_info *info)