From: iLag <ilagdoesntcheckthisemail@gmail.com>
Date: Sun, 26 Mar 2017 02:29:00 +0000 (-0700)
Subject: Add support for Master System cheats.
X-Git-Url: https://notaz.gp2x.de/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=fa55ee51c9c1d86311fbd90f055a575e4991ac70;p=picodrive.git

Add support for Master System cheats.
---

diff --git a/pico/memory.c b/pico/memory.c
index 4f38e5e2..e72628e6 100644
--- a/pico/memory.c
+++ b/pico/memory.c
@@ -459,7 +459,7 @@ static void PicoWrite16_sram(u32 a, u32 d)
 
 // z80 area (0xa00000 - 0xa0ffff)
 // TODO: verify mirrors VDP and bank reg (bank area mirroring verified)
-static u32 PicoRead8_z80(u32 a)
+u32 PicoRead8_z80(u32 a)
 {
   u32 d = 0xff;
   if ((Pico.m.z80Run & 1) || Pico.m.z80_reset) {
@@ -483,7 +483,7 @@ static u32 PicoRead16_z80(u32 a)
   return d | (d << 8);
 }
 
-static void PicoWrite8_z80(u32 a, u32 d)
+void PicoWrite8_z80(u32 a, u32 d)
 {
   if ((Pico.m.z80Run & 1) || Pico.m.z80_reset) {
     // verified on real hw
diff --git a/pico/patch.c b/pico/patch.c
index 558658c3..f08b3707 100644
--- a/pico/patch.c
+++ b/pico/patch.c
@@ -28,12 +28,13 @@ struct patch
 {
 	unsigned int addr;
 	unsigned short data;
+	unsigned char comp;
 };
 
 struct patch_inst *PicoPatches = NULL;
 int PicoPatchCount = 0;
 
-static char genie_chars[] = "AaBbCcDdEeFfGgHhJjKkLlMmNnPpRrSsTtVvWwXxYyZz0O1I2233445566778899";
+static char genie_chars_md[] = "AaBbCcDdEeFfGgHhJjKkLlMmNnPpRrSsTtVvWwXxYyZz0O1I2233445566778899";
 
 /* genie_decode
  * This function converts a Game Genie code to an address:data pair.
@@ -47,20 +48,23 @@ static char genie_chars[] = "AaBbCcDdEeFfGgHhJjKkLlMmNnPpRrSsTtVvWwXxYyZz0O1I223
  * by result. If an error results, both the address and data will be set to -1.
  */
 
-static void genie_decode(const char* code, struct patch* result)
+static void genie_decode_md(const char* code, struct patch* result)
 {
   int i = 0, n;
   char* x;
 
-  for(; i < 8; ++i)
+  for(; i < 9; ++i)
   {
+    /* Skip i=4; it's going to be the separating hyphen */
+    if (i==4) continue;
+
     /* If strchr returns NULL, we were given a bad character */
-    if(!(x = strchr(genie_chars, code[i])))
+    if(!(x = strchr(genie_chars_md, code[i])))
     {
       result->addr = -1; result->data = -1;
       return;
     }
-    n = (x - genie_chars) >> 1;
+    n = (x - genie_chars_md) >> 1;
     /* Now, based on which character this is, fit it into the result */
     switch(i)
     {
@@ -81,21 +85,21 @@ static void genie_decode(const char* code, struct patch* result)
       /* BCDE ____ ____ ___A ____ ____ : ____ ____ ____ ____ */
       result->addr |= (n & 0xF) << 20 | (n >> 4) << 8;
       break;
-    case 4:
+    case 5:
       /* ____ ABCD ____ ____ ____ ____ : ___E ____ ____ ____ */
       result->data |= (n & 1) << 12;
       result->addr |= (n >> 1) << 16;
       break;
-    case 5:
+    case 6:
       /* ____ ____ ____ ____ ____ ____ : E___ ABCD ____ ____ */
       result->data |= (n & 1) << 15 | (n >> 1) << 8;
       break;
-    case 6:
+    case 7:
       /* ____ ____ ____ ____ CDE_ ____ : _AB_ ____ ____ ____ */
       result->data |= (n >> 3) << 13;
       result->addr |= (n & 7) << 5;
       break;
-    case 7:
+    case 8:
       /* ____ ____ ____ ____ ___A BCDE : ____ ____ ____ ____ */
       result->addr |= n;
       break;
@@ -113,30 +117,165 @@ static void genie_decode(const char* code, struct patch* result)
 
 static char hex_chars[] = "00112233445566778899AaBbCcDdEeFf";
 
-static void hex_decode(const char *code, struct patch *result)
+static void hex_decode_md(const char *code, struct patch *result)
 {
   char *x;
   int i;
   /* 6 digits for address */
   for(i = 0; i < 6; ++i)
+  {
+    if(!(x = strchr(hex_chars, code[i])))
     {
-      if(!(x = strchr(hex_chars, code[i])))
-      {
-	result->addr = result->data = -1;
-	return;
-      }
-      result->addr = (result->addr << 4) | ((x - hex_chars) >> 1);
+      result->addr = result->data = -1;
+      return;
     }
+    result->addr = (result->addr << 4) | ((x - hex_chars) >> 1);
+  }
   /* 4 digits for data */
-  for(i = 6; i < 10; ++i)
+  for(i = 7; i < 11; ++i)
+  {
+    if(!(x = strchr(hex_chars, code[i])))
+    {
+      if (i==8) break;
+      result->addr = result->data = -1;
+      return;
+    }
+    result->data = (result->data << 4) | ((x - hex_chars) >> 1);
+  }
+}
+
+void genie_decode_ms(const char *code, struct patch *result)
+{
+  char *x;
+  int i;
+  /* 2 digits for data */
+  for(i=0;i<2;++i)
+  {
+    if(!(x = strchr(hex_chars, code[i])))
+    {
+      result->addr = result->data = -1;
+      return;
+    }
+    result->data = (result->data << 4) | ((x - hex_chars) >> 1);
+  }
+  /* 4 digits for address */
+  for(i=2;i<7;++i)
+  {
+    /* 4th character is hyphen and can be skipped*/
+    if (i==3) continue;
+    if(!(x = strchr(hex_chars, code[i])))
+    {
+      result->addr = result->data = -1;
+      return;
+    }
+    result->addr = (result->addr << 4) | ((x - hex_chars) >> 1);
+  }
+  /* Correct the address */
+  result->addr = ((result->addr >> 4) | (result->addr << 12 & 0xF000)) ^ 0xF000;
+  /* Optional: 3 digits for comp */
+  if (code[8]){
+    for(i=8;i<11;++i)
     {
+      if (i==9) continue; /* 2nd character is ignored */
       if(!(x = strchr(hex_chars, code[i])))
       {
 	result->addr = result->data = -1;
 	return;
       }
-      result->data = (result->data << 4) | ((x - hex_chars) >> 1);
+      result->comp = (result->comp << 4) | ((x - hex_chars) >> 1);
+    }
+    /* Correct the comp */
+    result->comp = ((result->comp >> 2) | ((result->comp << 6) & 0xC0)) ^ 0xBA;
+  }
+}
+
+void ar_decode_ms(const char *code, struct patch *result){
+  char *x;
+  int i;
+  /* 2 digits of padding*/
+  /* 4 digits for address */
+  for(i=2;i<7;++i)
+  {
+    /* 5th character is hyphen and can be skipped*/
+    if (i==4) continue;
+    if(!(x = strchr(hex_chars, code[i])))
+    {
+      result->addr = result->data = -1;
+      return;
+    }
+    result->addr = (result->addr << 4) | ((x - hex_chars) >> 1);
+  }
+  /* 2 digits for data */
+  for(i=7;i<9;++i)
+  {
+    if(!(x = strchr(hex_chars, code[i])))
+    {
+      result->addr = result->data = -1;
+      return;
+    }
+    result->data = (result->data << 4) | ((x - hex_chars) >> 1);
+  }
+}
+
+void fusion_ram_decode(const char *code, struct patch *result){
+  char *x;
+  int i;
+  /* 4 digits for address */
+  for(i=0;i<4;++i)
+  {
+    if(!(x = strchr(hex_chars, code[i])))
+    {
+      result->addr = result->data = -1;
+      return;
+    }
+    result->addr = (result->addr << 4) | ((x - hex_chars) >> 1);
+  }
+  /* Skip the ':' */
+  /* 2 digits for data */
+  for(i=5;i<7;++i)
+  {
+    if(!(x = strchr(hex_chars, code[i])))
+    {
+      result->addr = result->data = -1;
+      return;
+    }
+    result->data = (result->data << 4) | ((x - hex_chars) >> 1);
+  }
+}
+
+void fusion_rom_decode(const char *code, struct patch *result){
+  char *x;
+  int i;
+  /* 2 digits for comp */
+  for(i=0;i<2;++i)
+  {
+    if(!(x = strchr(hex_chars, code[i])))
+    {
+      result->addr = result->data = -1;
+      return;
     }
+    result->comp = (result->comp << 4) | ((x - hex_chars) >> 1);
+  }
+  /* 4 digits for address */
+  for(i=2;i<6;++i)
+  {
+    if(!(x = strchr(hex_chars, code[i])))
+    {
+      result->addr = result->data = -1;
+      return;
+    }
+    result->addr = (result->addr << 4) | ((x - hex_chars) >> 1);
+  }
+  /* 2 digits for data */
+  for(i=7;i<9;++i)
+  {
+    if(!(x = strchr(hex_chars, code[i])))
+    {
+      result->addr = result->data = -1;
+      return;
+    }
+    result->data = (result->data << 4) | ((x - hex_chars) >> 1);
+  }
 }
 
 /* THIS is the function you call from the MegaDrive or whatever. This figures
@@ -144,65 +283,72 @@ static void hex_decode(const char *code, struct patch *result)
  * decoder. */
 void decode(const char* code, struct patch* result)
 {
-  int len = strlen(code), i, j;
-  char code_to_pass[16], *x;
-  const char *ad, *da;
-  int adl, dal;
+  int len = strlen(code);
 
   /* Initialize the result */
-  result->addr = result->data = 0;
+  result->addr = result->data = result->comp = 0;
 
-  /* Just assume 8 char long string to be Game Genie code */
-  if (len == 8)
+  if(!(PicoAHW & PAHW_SMS))
   {
-    genie_decode(code, result);
-    return;
-  }
+    //If Genesis
 
-  /* If it's 9 chars long and the 5th is a hyphen, we have a Game Genie
-   * code. */
+    //Game Genie
     if(len == 9 && code[4] == '-')
     {
-      /* Remove the hyphen and pass to genie_decode */
-      code_to_pass[0] = code[0];
-      code_to_pass[1] = code[1];
-      code_to_pass[2] = code[2];
-      code_to_pass[3] = code[3];
-      code_to_pass[4] = code[5];
-      code_to_pass[5] = code[6];
-      code_to_pass[6] = code[7];
-      code_to_pass[7] = code[8];
-      code_to_pass[8] = '\0';
-      genie_decode(code_to_pass, result);
+      genie_decode_md(code, result);
       return;
     }
 
-  /* Otherwise, we assume it's a hex code.
-   * Find the colon so we know where address ends and data starts. If there's
-   * no colon, then we haven't a code at all! */
-  if(!(x = strchr(code, ':'))) goto bad_code;
-  ad = code; da = x + 1; adl = x - code; dal = len - adl - 1;
+    //Master
+    else if(len >=9 && code[6] == ':')
+    {
+      hex_decode_md(code, result);
+    }
+
+    else
+    {
+      goto bad_code;
+    }
+  } else {
+    //If Master System
 
-  /* If a section is empty or too long, toss it */
-  if(adl == 0 || adl > 6 || dal == 0 || dal > 4) goto bad_code;
+    //Genie
+    if(len == 11 && code[3] == '-' && code[7] == '-')
+    {
+      genie_decode_ms(code, result);
+    }
 
-  /* Pad the address with zeros, then fill it with the value */
-  for(i = 0; i < (6 - adl); ++i) code_to_pass[i] = '0';
-  for(j = 0; i < 6; ++i, ++j) code_to_pass[i] = ad[j];
+    //AR
+    else if(len == 9 && code[4] == '-')
+    {
+      ar_decode_ms(code, result);
+    }
 
-  /* Do the same for data */
-  for(i = 6; i < (10 - dal); ++i) code_to_pass[i] = '0';
-  for(j = 0; i < 10; ++i, ++j) code_to_pass[i] = da[j];
+    //Fusion RAM
+    else if(len == 7 && code[4] == ':')
+    {
+      fusion_ram_decode(code, result);
+    }
 
-  code_to_pass[10] = '\0';
+    //Fusion ROM
+    else if(len == 9 && code[6] == ':')
+    {
+      fusion_rom_decode(code, result);
+    }
 
-  /* Decode and goodbye */
-  hex_decode(code_to_pass, result);
-  return;
+    else
+    {
+      goto bad_code;
+    }
 
-bad_code:
+    //Convert RAM address space to Genesis location.
+    if (result->addr>=0xC000)
+      result->addr= 0xFF0000 | (0x1FFF & result->addr);
+  }
 
-  /* AGH! Invalid code! */
+  return;
+
+  bad_code:
   result->data = result->addr = -1;
   return;
 }
@@ -212,7 +358,9 @@ bad_code:
 unsigned int PicoRead16(unsigned int a);
 void PicoWrite16(unsigned int a, unsigned short d);
 extern unsigned short m68k_read16(unsigned int a);
-extern void m68k_write16(int a, unsigned short d);
+extern void m68k_write16(unsigned int a, unsigned short d);
+extern char PicoRead8_z80(unsigned short a);
+extern void PicoWrite8_z80(unsigned short a, char d);
 
 void PicoPatchUnload(void)
 {
@@ -293,54 +441,84 @@ int PicoPatchLoad(const char *fname)
 /* to be called when the Rom is loaded and byteswapped */
 void PicoPatchPrepare(void)
 {
-	int i;
+  int i;
+  int addr;
 
-	for (i = 0; i < PicoPatchCount; i++)
-	{
-		PicoPatches[i].addr &= ~1;
-		if (PicoPatches[i].addr < Pico.romsize)
-			PicoPatches[i].data_old = *(unsigned short *)(Pico.rom + PicoPatches[i].addr);
-		else
-			PicoPatches[i].data_old = (unsigned short) m68k_read16(PicoPatches[i].addr);
-		if (strstr(PicoPatches[i].name, "AUTO"))
-			PicoPatches[i].active = 1;
-	}
+  for (i = 0; i < PicoPatchCount; i++)
+  {
+    addr=PicoPatches[i].addr;
+    addr &= ~1;
+    if (addr < Pico.romsize)
+      PicoPatches[i].data_old = *(unsigned short *)(Pico.rom + addr);
+    else
+    {
+      if(!(PicoAHW & PAHW_SMS))
+	PicoPatches[i].data_old = (unsigned short) m68k_read16(addr);
+      else
+	PicoPatches[i].data_old = (unsigned char) PicoRead8_z80(addr);
+    }
+    if (strstr(PicoPatches[i].name, "AUTO"))
+      PicoPatches[i].active = 1;
+  }
 }
 
 void PicoPatchApply(void)
 {
-	int i, u;
-	unsigned int addr;
+  int i, u;
+  unsigned int addr;
+
+  for (i = 0; i < PicoPatchCount; i++)
+  {
+    addr = PicoPatches[i].addr;
 
-	for (i = 0; i < PicoPatchCount; i++)
+    if (addr < Pico.romsize)
+    {
+      if (PicoPatches[i].active)
+      {
+	if (!(PicoAHW & PAHW_SMS))
+	  *(unsigned short *)(Pico.rom + addr) = PicoPatches[i].data;
+	else if (!PicoPatches[i].comp || PicoPatches[i].comp == *(char *)(Pico.rom + addr))
+	  *(char *)(Pico.rom + addr) = (char) PicoPatches[i].data;
+      }
+      else
+      {
+	// if current addr is not patched by older patch, write back original val
+	for (u = 0; u < i; u++)
+	  if (PicoPatches[u].addr == addr) break;
+	if (u == i)
 	{
-		addr = PicoPatches[i].addr;
-		if (addr < Pico.romsize)
-		{
-			if (PicoPatches[i].active)
-				*(unsigned short *)(Pico.rom + addr) = PicoPatches[i].data;
-			else {
-				// if current addr is not patched by older patch, write back original val
-				for (u = 0; u < i; u++)
-					if (PicoPatches[u].addr == addr) break;
-				if (u == i)
-					*(unsigned short *)(Pico.rom + addr) = PicoPatches[i].data_old;
-			}
-			// fprintf(stderr, "patched %i: %06x:%04x\n", PicoPatches[i].active, addr,
-			//	*(unsigned short *)(Pico.rom + addr));
-		}
-		else
-		{
-			if (PicoPatches[i].active)
-				m68k_write16(PicoPatches[i].addr,PicoPatches[i].data);
-			else {
-				// if current addr is not patched by older patch, write back original val
-				for (u = 0; u < i; u++)
-					if (PicoPatches[u].addr == addr) break;
-				if (u == i)
-					m68k_write16(PicoPatches[i].addr,PicoPatches[i].data_old);
-			}
-		}
+	  if (!(PicoAHW & PAHW_SMS))
+	    *(unsigned short *)(Pico.rom + addr) = PicoPatches[i].data_old;
+	  else
+	    *(char *)(Pico.rom + addr) = (char) PicoPatches[i].data_old;
+	}
+      }
+      // fprintf(stderr, "patched %i: %06x:%04x\n", PicoPatches[i].active, addr,
+      //	*(unsigned short *)(Pico.rom + addr));
+    }
+    else
+    {
+      if (PicoPatches[i].active)
+      {
+	if (!(PicoAHW & PAHW_SMS))
+	  m68k_write16(addr,PicoPatches[i].data);
+	else
+	  PicoWrite8_z80(addr,PicoPatches[i].data);
+      }
+      else
+      {
+	// if current addr is not patched by older patch, write back original val
+	for (u = 0; u < i; u++)
+	  if (PicoPatches[u].addr == addr) break;
+	if (u == i)
+	{
+	  if (!(PicoAHW & PAHW_SMS))
+	    m68k_write16(PicoPatches[i].addr,PicoPatches[i].data_old);
+	  else
+	    PicoWrite8_z80(PicoPatches[i].addr,PicoPatches[i].data_old);
 	}
+      }
+    }
+  }
 }
 
diff --git a/pico/patch.h b/pico/patch.h
index 6e9420f8..9ab86d36 100644
--- a/pico/patch.h
+++ b/pico/patch.h
@@ -13,6 +13,7 @@ struct patch_inst
 	unsigned int addr;
 	unsigned short data;
 	unsigned short data_old;
+	unsigned char comp;
 };
 
 extern struct patch_inst *PicoPatches;
diff --git a/platform/libretro/libretro.c b/platform/libretro/libretro.c
index f11b5dae..a1cf22c8 100644
--- a/platform/libretro/libretro.c
+++ b/platform/libretro/libretro.c
@@ -696,6 +696,7 @@ typedef struct patch
 {
 	unsigned int addr;
 	unsigned short data;
+	unsigned char comp;
 } patch;
 
 extern void decode(char *buff, patch *dest);
@@ -728,16 +729,10 @@ void retro_cheat_set(unsigned index, bool enabled, const char *code)
 	int array_len = PicoPatchCount;
 	char codeCopy[256];
 	char *buff;
-	bool multiline=0;
 
+	if (code=='\0') return;
 	strcpy(codeCopy,code);
-	
-	if (strstr(code,"+")){
-		multiline=1;
-		buff = strtok(codeCopy,"+");
-	} else {
-		buff=codeCopy;
-	}
+	buff = strtok(codeCopy,"+");
 
 	while (buff != NULL)
 	{
@@ -766,14 +761,13 @@ void retro_cheat_set(unsigned index, bool enabled, const char *code)
 		PicoPatches[PicoPatchCount].active = enabled;
 		PicoPatches[PicoPatchCount].addr = pt.addr;
 		PicoPatches[PicoPatchCount].data = pt.data;
+		PicoPatches[PicoPatchCount].comp = pt.comp;
 		if (PicoPatches[PicoPatchCount].addr < Pico.romsize)
 			PicoPatches[PicoPatchCount].data_old = *(uint16_t *)(Pico.rom + PicoPatches[PicoPatchCount].addr);
 		else
 			PicoPatches[PicoPatchCount].data_old = (uint16_t) m68k_read16(PicoPatches[PicoPatchCount].addr);
 		PicoPatchCount++;
 
-		if (!multiline)
-			break;
 		buff = strtok(NULL,"+");
 	}
 }