license info added to Pico directory

[cyclone68000.git] / Pico / Pico.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
\r
// 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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int PicoVer=0x0030;\r
struct Pico Pico;\r
int PicoOpt=0;\r
\r
int PicoPad[2]; // Joypads, format is SACB RLDU\r
\r
int PicoInit()\r
{\r
  // Blank space for state:\r
  memset(&Pico,0,sizeof(Pico));\r
  memset(&PicoPad,0,sizeof(PicoPad));\r
  Pico.m.dirtyPal=1;\r
\r
  // Init CPU:\r
  SekInit();\r
\r
  // Setup memory callbacks:\r
  PicoMemInit();\r
  PsndReset();\r
\r
#ifdef MSOUND\r
  YM2612Init(1,7670443,PsndRate,NULL,NULL);\r
#endif\r
  return 0;\r
}\r
\r
void PicoExit()\r
{\r
#ifdef MSOUND\r
  YM2612Shutdown();\r
#endif\r
\r
  memset(&Pico,0,sizeof(Pico));\r
}\r
\r
int PicoReset()\r
{\r
  unsigned int region=0;\r
  int support=0,hw=0,i=0;\r
  unsigned char pal=0;\r
\r
  if (Pico.romsize<=0) return 1;\r
\r
  SekReset();\r
  PsndReset();\r
#ifdef MSOUND\r
  YM2612ResetChip(0);\r
#endif\r
\r
  // Read cartridge region data:\r
  region=PicoRead32(0x1f0);\r
\r
  for (i=0;i<4;i++)\r
  {\r
    int c=0;\r
    \r
    c=region>>(i<<3); c&=0xff;\r
    if (c<=' ') continue;\r
\r
         if (c=='J') support|=1;\r
    else if (c=='U') support|=4;\r
    else if (c=='E') support|=8;\r
    else\r
    {\r
      // New style code:\r
      char s[2]={0,0};\r
      s[0]=(char)c;\r
      support|=strtol(s,NULL,16);\r
    }\r
\r
  }\r
\r
  // Try to pick the best hardware value for English/60hz:\r
       if (support&4)   hw=0x80;          // USA\r
  else if (support&8) { hw=0xc0; pal=1; } // Europe\r
  else if (support&1)   hw=0x00;          // Japan NTSC\r
  else if (support&2) { hw=0x40; pal=1; } // Japan PAL\r
  else hw=0x80; // USA\r
\r
  Pico.m.hardware=(unsigned char)(hw|0x20); // No disk attached\r
  Pico.m.pal=pal;\r
\r
  return 0;\r
}\r
\r
static int CheckIdle()\r
{\r
  unsigned char state[0x88];\r
\r
  memset(state,0,sizeof(state));\r
\r
  // See if the state is the same after 2 steps:\r
  SekState(state); SekRun(0); SekRun(0); SekState(state+0x44);\r
  if (memcmp(state,state+0x44,0x44)==0) return 1;\r
\r
  return 0;\r
}\r
\r
// Accurate but slower frame which does hints\r
static int PicoFrameHints()\r
{\r
  struct PicoVideo *pv=&Pico.video;\r
  int total=0,aim=0;\r
  int y=0;\r
  int hint=0x400; // Hint counter\r
\r
  pv->status|=0x08; // Go into vblank\r
\r
  for (y=-38;y<224;y++)\r
  {\r
    if (y==0)\r
    {\r
      hint=pv->reg[10]; // Load H-Int counter\r
      if (pv->reg[1]&0x40) pv->status&=~8; // Come out of vblank if display enabled\r
    }\r
\r
    // H-Interrupts:\r
    if (hint<0)\r
    {\r
      hint=pv->reg[10]; // Reload H-Int counter\r
      if (pv->reg[0]&0x10) SekInterrupt(4);\r
    }\r
\r
    // V-Interrupt:\r
    if (y==-37)\r
    {\r
      pv->status|=0x80; // V-Int happened\r
      if (pv->reg[1]&0x20) SekInterrupt(6);\r
    }\r
\r
    Pico.m.scanline=(short)y;\r
\r
    // Run scanline:\r
    aim+=489; total+=SekRun(aim-total);\r
\r
    hint--;\r
\r
    if (PicoScan && y>=0) PicoLine(y);\r
  }\r
\r
  SekInterrupt(0); // Cancel interrupt\r
\r
  return 0;\r
}\r
\r
// Simple frame without H-Ints\r
static int PicoFrameSimple()\r
{\r
  int total=0,y=0,aim=0;\r
  \r
  Pico.m.scanline=-64;\r
\r
  // V-Blanking period:\r
  if (Pico.video.reg[1]&0x20) SekInterrupt(6); // Set IRQ\r
  Pico.video.status|=0x88; // V-Int happened / go into vblank\r
  total+=SekRun(18560);\r
\r
  // Active Scan:\r
  if (Pico.video.reg[1]&0x40) Pico.video.status&=~8; // Come out of vblank if display is enabled\r
  SekInterrupt(0); // Clear IRQ\r
\r
  // Run in sections:\r
  for (aim=18560+6839; aim<=18560+6839*16; aim+=6839)\r
  {\r
    int add=0;\r
    if (CheckIdle()) break;\r
    add=SekRun(aim-total);\r
    total+=add;\r
  }\r
\r
  if (PicoMask&0x100)\r
  if (PicoScan)\r
  {\r
    // Draw the screen\r
    for (y=0;y<224;y++) PicoLine(y);\r
  }\r
\r
  return 0;\r
}\r
\r
int PicoFrame()\r
{\r
  int hints=0;\r
\r
  if (Pico.rom==NULL) return 1; // No Rom plugged in\r
\r
\r
  PmovUpdate();\r
\r
  hints=Pico.video.reg[0]&0x10;\r
\r
  if (hints) PicoFrameHints();\r
  else PicoFrameSimple();\r
\r
  PsndRender();\r
\r
  return 0;\r
}\r
\r
static int DefaultCram(int cram)\r
{\r
  int high=0x0841;\r
  // Convert 0000bbbb ggggrrrr\r
  // to      rrrr1ggg g10bbbb1\r
  high|=(cram&0x00f)<<12; // Red\r
  high|=(cram&0x0f0)<< 3; // Green\r
  high|=(cram&0xf00)>> 7; // Blue\r
  return high;\r
}\r
\r
// Function to convert Megadrive Cram into a native colour:\r
int (*PicoCram)(int cram)=DefaultCram;\r