Pico/carthw/svp/svp.c

   1 // The SVP chip emulator
   2
   3 // (c) Copyright 2008, Grazvydas "notaz" Ignotas
   4 // Free for non-commercial use.
   5
   6 // For commercial use, separate licencing terms must be obtained.
   7
   8
   9 #include "../../PicoInt.h"
  10
  11 svp_t *svp = NULL;
  12 int PicoSVPCycles = 800; // cycles/line
  13
  14 static void PicoSVPReset(void)
  15 {
  16         elprintf(EL_SVP, "SVP reset");
  17
  18         memcpy(svp->iram_rom + 0x800, Pico.rom + 0x800, 0x20000 - 0x800);
  19         ssp1601_reset(&svp->ssp1601);
  20 }
  21
  22
  23 static void PicoSVPLine(int count)
  24 {
  25         // ???
  26         // OSC_NTSC / 3.0 / 60.0 / 262.0 ~= 1139
  27         // OSC_PAL  / 3.0 / 50.0 / 312.0 ~= 1137
  28         ssp1601_run(PicoSVPCycles * count);
  29
  30         // test mode
  31         //if (Pico.m.frame_count == 13) PicoPad[0] |= 0xff;
  32 }
  33
  34
  35 static int PicoSVPDma(unsigned int source, int len, unsigned short **srcp, unsigned short **limitp)
  36 {
  37         if (source < Pico.romsize) // Rom
  38         {
  39                 source -= 2;
  40                 *srcp = (unsigned short *)(Pico.rom + (source&~1));
  41                 *limitp = (unsigned short *)(Pico.rom + Pico.romsize);
  42                 return 1;
  43         }
  44         else if ((source & 0xfe0000) == 0x300000)
  45         {
  46                 elprintf(EL_VDPDMA|EL_SVP, "SVP DmaSlow from %06x, len=%i", source, len);
  47                 source &= 0x1fffe;
  48                 source -= 2;
  49                 *srcp = (unsigned short *)(svp->dram + source);
  50                 *limitp = (unsigned short *)(svp->dram + sizeof(svp->dram));
  51                 return 1;
  52         }
  53         else
  54                 elprintf(EL_VDPDMA|EL_SVP|EL_ANOMALY, "SVP FIXME unhandled DmaSlow from %06x, len=%i", source, len);
  55
  56         return 0;
  57 }
  58
  59
  60 void PicoSVPInit(void)
  61 {
  62         void *tmp;
  63
  64         elprintf(EL_SVP, "SVP init");
  65
  66         tmp = realloc(Pico.rom, 0x200000 + sizeof(*svp));
  67         if (tmp == NULL)
  68         {
  69                 elprintf(EL_STATUS|EL_SVP, "OOM for SVP data");
  70                 return;
  71         }
  72
  73         Pico.rom = tmp;
  74         svp = (void *) ((char *)tmp + 0x200000);
  75         memset(svp, 0, sizeof(*svp));
  76
  77         // init ok, setup hooks..
  78         PicoRead16Hook = PicoSVPRead16;
  79         PicoWrite8Hook = PicoSVPWrite8;
  80         PicoWrite16Hook = PicoSVPWrite16;
  81         PicoDmaHook = PicoSVPDma;
  82         PicoResetHook = PicoSVPReset;
  83         PicoLineHook = PicoSVPLine;
  84 }
  85