mirror of
https://github.com/ekeeke/Genesis-Plus-GX.git
synced 2024-09-21 05:39:43 +02:00
Implement cheatcode support - implement retro_cheat_reset/retro_cheat_set
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twinaphex
parent
41c1f4fe70
commit
8b4b807b8c
@ -81,6 +81,32 @@ static retro_input_state_t input_state_cb;
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static retro_environment_t environ_cb;
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static retro_audio_sample_batch_t audio_cb;
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/* Cheat Support */
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#define MAX_CHEATS (150)
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#define MAX_DESC_LENGTH (63)
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typedef struct
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{
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char code[12];
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char text[MAX_DESC_LENGTH];
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uint8_t enable;
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uint16_t data;
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uint16_t old;
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uint32_t address;
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uint8_t *prev;
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} CHEATENTRY;
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static int maxcheats = 0;
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static int maxROMcheats = 0;
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static int maxRAMcheats = 0;
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static CHEATENTRY cheatlist[MAX_CHEATS];
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static uint8_t cheatIndexes[MAX_CHEATS];
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static char ggvalidchars[] = "ABCDEFGHJKLMNPRSTVWXYZ0123456789";
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static char arvalidchars[] = "0123456789ABCDEF";
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/************************************
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* Genesis Plus GX implementation
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************************************/
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@ -169,6 +195,8 @@ int load_archive(char *filename, unsigned char *buffer, int maxsize, char *exten
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return size;
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}
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void RAMCheatUpdate(void);
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void osd_input_update(void)
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{
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int i, player = 0;
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@ -176,6 +204,9 @@ void osd_input_update(void)
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input_poll_cb();
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/* Update RAM patches */
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RAMCheatUpdate();
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for (i = 0; i < MAX_INPUTS; i++)
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{
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temp = 0;
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@ -941,6 +972,314 @@ static void check_variables(void)
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}
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}
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/* Cheat Support */
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static uint32_t decode_cheat(char *string, int index)
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{
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char *p;
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int i,n;
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uint32_t len = 0;
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uint32_t address = 0;
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uint16_t data = 0;
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uint8_t ref = 0;
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/* 16-bit Game Genie code (ABCD-EFGH) */
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if ((strlen(string) >= 9) && (string[4] == '-'))
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{
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/* 16-bit system only */
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if ((system_hw & SYSTEM_PBC) != SYSTEM_MD)
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{
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return 0;
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}
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for (i = 0; i < 8; i++)
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{
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if (i == 4) string++;
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p = strchr (ggvalidchars, *string++);
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if (p == NULL) return 0;
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n = p - ggvalidchars;
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switch (i)
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{
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case 0:
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data |= n << 3;
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break;
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case 1:
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data |= n >> 2;
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address |= (n & 3) << 14;
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break;
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case 2:
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address |= n << 9;
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break;
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case 3:
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address |= (n & 0xF) << 20 | (n >> 4) << 8;
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break;
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case 4:
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data |= (n & 1) << 12;
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address |= (n >> 1) << 16;
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break;
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case 5:
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data |= (n & 1) << 15 | (n >> 1) << 8;
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break;
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case 6:
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data |= (n >> 3) << 13;
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address |= (n & 7) << 5;
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break;
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case 7:
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address |= n;
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break;
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}
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}
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/* code length */
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len = 9;
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}
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/* 8-bit Game Genie code (DDA-AAA-XXX) */
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else if ((strlen(string) >= 11) && (string[3] == '-') && (string[7] == '-'))
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{
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/* 8-bit system only */
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if ((system_hw & SYSTEM_PBC) == SYSTEM_MD)
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{
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return 0;
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}
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/* decode 8-bit data */
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for (i=0; i<2; i++)
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{
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p = strchr (arvalidchars, *string++);
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if (p == NULL) return 0;
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n = (p - arvalidchars) & 0xF;
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data |= (n << ((1 - i) * 4));
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}
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/* decode 16-bit address (low 12-bits) */
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for (i=0; i<3; i++)
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{
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if (i==1) string++; /* skip separator */
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p = strchr (arvalidchars, *string++);
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if (p == NULL) return 0;
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n = (p - arvalidchars) & 0xF;
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address |= (n << ((2 - i) * 4));
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}
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/* decode 16-bit address (high 4-bits) */
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p = strchr (arvalidchars, *string++);
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if (p == NULL) return 0;
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n = (p - arvalidchars) & 0xF;
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n ^= 0xF; /* bits inversion */
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address |= (n << 12);
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/* RAM address are also supported */
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if (address >= 0xC000)
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{
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/* convert to 24-bit Work RAM address */
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address = 0xFF0000 | (address & 0x1FFF);
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}
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/* decode reference 8-bit data */
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for (i=0; i<2; i++)
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{
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string++; /* skip separator and 2nd digit */
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p = strchr (arvalidchars, *string++);
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if (p == NULL) return 0;
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n = (p - arvalidchars) & 0xF;
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ref |= (n << ((1 - i) * 4));
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}
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ref = (ref >> 2) | ((ref & 0x03) << 6); /* 2-bit right rotation */
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ref ^= 0xBA; /* XOR */
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/* update old data value */
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cheatlist[index].old = ref;
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/* code length */
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len = 11;
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}
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/* Action Replay code */
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else if (string[6] == ':')
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{
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if ((system_hw & SYSTEM_PBC) == SYSTEM_MD)
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{
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/* 16-bit code (AAAAAA:DDDD) */
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if (strlen(string) < 11) return 0;
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/* decode 24-bit address */
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for (i=0; i<6; i++)
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{
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p = strchr (arvalidchars, *string++);
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if (p == NULL) return 0;
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n = (p - arvalidchars) & 0xF;
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address |= (n << ((5 - i) * 4));
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}
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/* decode 16-bit data */
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string++;
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for (i=0; i<4; i++)
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{
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p = strchr (arvalidchars, *string++);
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if (p == NULL) return 0;
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n = (p - arvalidchars) & 0xF;
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data |= (n << ((3 - i) * 4));
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}
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/* code length */
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len = 11;
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}
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else
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{
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/* 8-bit code (xxAAAA:DD) */
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if (strlen(string) < 9) return 0;
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/* decode 16-bit address */
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string+=2;
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for (i=0; i<4; i++)
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{
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p = strchr (arvalidchars, *string++);
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if (p == NULL) return 0;
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n = (p - arvalidchars) & 0xF;
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address |= (n << ((3 - i) * 4));
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}
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/* ROM addresses are not supported */
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if (address < 0xC000) return 0;
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/* convert to 24-bit Work RAM address */
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address = 0xFF0000 | (address & 0x1FFF);
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/* decode 8-bit data */
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string++;
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for (i=0; i<2; i++)
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{
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p = strchr (arvalidchars, *string++);
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if (p == NULL) return 0;
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n = (p - arvalidchars) & 0xF;
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data |= (n << ((1 - i) * 4));
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}
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/* code length */
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len = 9;
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}
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}
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/* Valid code found ? */
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if (len)
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{
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/* update cheat address & data values */
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cheatlist[index].address = address;
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cheatlist[index].data = data;
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cheatlist[index].enable = 1; // Enable the cheat by default
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}
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/* return code length (0 = invalid) */
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return len;
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}
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static void apply_cheats(void)
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{
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uint8_t *ptr;
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/* clear ROM&RAM patches counter */
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maxROMcheats = maxRAMcheats = 0;
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int i;
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for (i = 0; i < maxcheats; i++)
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{
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if (cheatlist[i].enable)
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{
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if (cheatlist[i].address < cart.romsize)
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{
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if ((system_hw & SYSTEM_PBC) == SYSTEM_MD)
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{
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/* patch ROM data */
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cheatlist[i].old = *(uint16_t *)(cart.rom + (cheatlist[i].address & 0xFFFFFE));
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*(uint16_t *)(cart.rom + (cheatlist[i].address & 0xFFFFFE)) = cheatlist[i].data;
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}
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else
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{
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/* add ROM patch */
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maxROMcheats++;
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cheatIndexes[MAX_CHEATS - maxROMcheats] = i;
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/* get current banked ROM address */
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ptr = &z80_readmap[(cheatlist[i].address) >> 10][cheatlist[i].address & 0x03FF];
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/* check if reference matches original ROM data */
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if (((uint8_t)cheatlist[i].old) == *ptr)
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{
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/* patch data */
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*ptr = cheatlist[i].data;
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/* save patched ROM address */
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cheatlist[i].prev = ptr;
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}
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else
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{
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/* no patched ROM address yet */
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cheatlist[i].prev = NULL;
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}
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}
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}
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else if (cheatlist[i].address >= 0xFF0000)
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{
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/* add RAM patch */
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cheatIndexes[maxRAMcheats++] = i;
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}
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}
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}
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}
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static void clear_cheats(void)
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{
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int i = maxcheats;
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/* disable cheats in reversed order in case the same address is used by multiple patches */
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while (i > 0)
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{
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if (cheatlist[i-1].enable)
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{
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if (cheatlist[i-1].address < cart.romsize)
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{
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if ((system_hw & SYSTEM_PBC) == SYSTEM_MD)
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{
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/* restore original ROM data */
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*(uint16_t *)(cart.rom + (cheatlist[i-1].address & 0xFFFFFE)) = cheatlist[i-1].old;
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}
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else
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{
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/* check if previous banked ROM address has been patched */
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if (cheatlist[i-1].prev != NULL)
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{
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/* restore original data */
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*cheatlist[i-1].prev = cheatlist[i-1].old;
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/* no more patched ROM address */
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cheatlist[i-1].prev = NULL;
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}
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}
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}
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}
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i--;
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}
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}
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static void remove_cheats(void)
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{
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int i = maxcheats;
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while (i > 0)
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{
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if (cheatlist[i-1].enable)
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{
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cheatlist[i-1].text[0] = 0;
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cheatlist[i-1].code[0] = 0;
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cheatlist[i-1].address = 0;
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cheatlist[i-1].data = 0;
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cheatlist[i-1].enable = 0;
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maxcheats--;
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}
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i--;
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}
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}
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/****************************************************************************
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* RAMCheatUpdate
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*
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* Apply RAM patches (this should be called once per frame)
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*
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****************************************************************************/
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void RAMCheatUpdate(void)
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{
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int index, cnt = maxRAMcheats;
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while (cnt)
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{
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/* get cheat index */
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index = cheatIndexes[--cnt];
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/* apply RAM patch */
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//if (cheatlist[index].data & 0xFF00)
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if (cheatlist[index].data & 0x00FF) // For LSB?
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{
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/* word patch */
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*(uint16_t *)(work_ram + (cheatlist[index].address & 0xFFFE)) = cheatlist[index].data;
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}
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else
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{
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/* byte patch */
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work_ram[cheatlist[index].address & 0xFFFF] = cheatlist[index].data;
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}
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}
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}
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/************************************
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* libretro implementation
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************************************/
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@ -1173,12 +1512,24 @@ bool retro_unserialize(const void *data, size_t size)
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return TRUE;
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}
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void retro_cheat_reset(void) {}
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void retro_cheat_reset(void)
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{
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/* clear existing ROM patches */
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clear_cheats();
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/* remove cheats from the list */
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remove_cheats();
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}
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void retro_cheat_set(unsigned index, bool enabled, const char *code)
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{
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(void)index;
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(void)enabled;
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(void)code;
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/* clear existing ROM patches */
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clear_cheats();
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/* interpret code and give it an index */
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decode_cheat((char *)code, maxcheats);
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/* increment cheat count */
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maxcheats++;
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/* apply ROM patches */
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apply_cheats();
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}
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bool retro_load_game(const struct retro_game_info *info)
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