license info added to Pico directory

[cyclone68000.git] / Pico / Cart.cpp

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// This file is part of the PicoDrive Megadrive Emulator\r
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// This code is licensed under the GNU General Public License version 2.0 and the MAME License.\r
// You can choose the license that has the most advantages for you.\r
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// SVN repository can be found at http://code.google.com/p/cyclone68000/\r
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#include "PicoInt.h"\r
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static void Byteswap(unsigned char *data,int len)\r
{\r
  int i=0;\r
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  if (len<2) return; // Too short\r
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  do\r
  {\r
    unsigned short *pd=(unsigned short *)(data+i);\r
    int value=*pd; // Get 2 bytes\r
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    value=(value<<8)|(value>>8); // Byteswap it\r
    *pd=(unsigned short)value; // Put 2b ytes\r
    i+=2;\r
  }  \r
  while (i+2<=len);\r
}\r
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// Interleve a 16k block and byteswap\r
static int InterleveBlock(unsigned char *dest,unsigned char *src)\r
{\r
  int i=0;\r
  for (i=0;i<0x2000;i++) dest[(i<<1)  ]=src[       i]; // Odd\r
  for (i=0;i<0x2000;i++) dest[(i<<1)+1]=src[0x2000+i]; // Even\r
  return 0;\r
}\r
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// Decode a SMD file\r
static int DecodeSmd(unsigned char *data,int len)\r
{\r
  unsigned char *temp=NULL;\r
  int i=0;\r
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  temp=(unsigned char *)malloc(0x4000);\r
  if (temp==NULL) return 1;\r
  memset(temp,0,0x4000);\r
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  // Interleve each 16k block and shift down by 0x200:\r
  for (i=0; i+0x4200<=len; i+=0x4000)\r
  {\r
    InterleveBlock(temp,data+0x200+i); // Interleve 16k to temporary buffer\r
    memcpy(data+i,temp,0x4000); // Copy back in\r
  }\r
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  free(temp);\r
  return 0;\r
}\r
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int PicoCartLoad(FILE *f,unsigned char **prom,unsigned int *psize)\r
{\r
  unsigned char *rom=NULL; int size=0;\r
  if (f==NULL) return 1;\r
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  fseek(f,0,SEEK_END); size=ftell(f); fseek(f,0,SEEK_SET);\r
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  size=(size+3)&~3; // Round up to a multiple of 4\r
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  // Allocate space for the rom plus padding\r
  rom=(unsigned char *)malloc(size+4);\r
  if (rom==NULL) { fclose(f); return 1; }\r
  memset(rom,0,size+4);\r
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  fread(rom,1,size,f); // Load up the rom\r
  fclose(f);\r
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  // Check for SMD:\r
  if ((size&0x3fff)==0x200) { DecodeSmd(rom,size); size-=0x200; } // Decode and byteswap SMD\r
  else Byteswap(rom,size); // Just byteswap\r
  \r
  if (prom)  *prom=rom;\r
  if (psize) *psize=size;\r
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  return 0;\r
}\r
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// Insert/remove a cartridge:\r
int PicoCartInsert(unsigned char *rom,unsigned int romsize)\r
{\r
  // Make sure movie playing/recording is stopped:\r
  if (PmovFile) fclose(PmovFile);\r
  PmovFile=NULL; PmovAction=0;\r
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  memset(&Pico,0,sizeof(Pico)); // Blank Pico state\r
  Pico.rom=rom;\r
  Pico.romsize=romsize;\r
  PicoReset();\r
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  return 0;\r
}\r