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 = 1000; // 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         ssp1601_run(PicoSVPCycles * count);
  27
  28         // test mode
  29         //if (Pico.m.frame_count == 13) PicoPad[0] |= 0xff;
  30 }
  31
  32
  33 static int PicoSVPDma(unsigned int source, int len, unsigned short **srcp, unsigned short **limitp)
  34 {
  35         if (source < Pico.romsize) // Rom
  36         {
  37                 source -= 2;
  38                 *srcp = (unsigned short *)(Pico.rom + (source&~1));
  39                 *limitp = (unsigned short *)(Pico.rom + Pico.romsize);
  40                 return 1;
  41         }
  42         else if ((source & 0xfe0000) == 0x300000)
  43         {
  44                 elprintf(EL_VDPDMA|EL_SVP, "SVP DmaSlow from %06x, len=%i", source, len);
  45                 source &= 0x1fffe;
  46                 source -= 2;
  47                 *srcp = (unsigned short *)(svp->dram + source);
  48                 *limitp = (unsigned short *)(svp->dram + sizeof(svp->dram));
  49                 return 1;
  50         }
  51         else
  52                 elprintf(EL_VDPDMA|EL_SVP|EL_ANOMALY, "SVP FIXME unhandled DmaSlow from %06x, len=%i", source, len);
  53
  54         return 0;
  55 }
  56
  57
  58 void PicoSVPInit(void)
  59 {
  60         void *tmp;
  61
  62         elprintf(EL_SVP, "SVP init");
  63
  64         tmp = realloc(Pico.rom, 0x200000 + sizeof(*svp));
  65         if (tmp == NULL)
  66         {
  67                 elprintf(EL_STATUS|EL_SVP, "OOM for SVP data");
  68                 return;
  69         }
  70
  71         Pico.rom = tmp;
  72         svp = (void *) ((char *)tmp + 0x200000);
  73         memset(svp, 0, sizeof(*svp));
  74
  75         // init ok, setup hooks..
  76         PicoRead16Hook = PicoSVPRead16;
  77         PicoWrite8Hook = PicoSVPWrite8;
  78         PicoWrite16Hook = PicoSVPWrite16;
  79         PicoDmaHook = PicoSVPDma;
  80         PicoResetHook = PicoSVPReset;
  81         PicoLineHook = PicoSVPLine;
  82 }
  83