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 /* save state stuff */
  15 typedef enum {
  16         CHUNK_IRAM = CHUNK_CARTHW,
  17         CHUNK_DRAM,
  18         CHUNK_SSP
  19 } chunk_name_e;
  20
  21 static carthw_state_chunk svp_states[] =
  22 {
  23         { CHUNK_IRAM, 0x800,                 NULL },
  24         { CHUNK_DRAM, sizeof(svp->dram),     NULL },
  25         { CHUNK_SSP,  sizeof(svp->ssp1601),  NULL },
  26         { 0,          0,                     NULL }
  27 };
  28
  29
  30 static void PicoSVPReset(void)
  31 {
  32         elprintf(EL_SVP, "SVP reset");
  33
  34         memcpy(svp->iram_rom + 0x800, Pico.rom + 0x800, 0x20000 - 0x800);
  35         ssp1601_reset(&svp->ssp1601);
  36 }
  37
  38
  39 static void PicoSVPLine(int count)
  40 {
  41         // ???
  42         ssp1601_run(PicoSVPCycles * count);
  43
  44         // test mode
  45         //if (Pico.m.frame_count == 13) PicoPad[0] |= 0xff;
  46 }
  47
  48
  49 static int PicoSVPDma(unsigned int source, int len, unsigned short **srcp, unsigned short **limitp)
  50 {
  51         if (source < Pico.romsize) // Rom
  52         {
  53                 source -= 2;
  54                 *srcp = (unsigned short *)(Pico.rom + (source&~1));
  55                 *limitp = (unsigned short *)(Pico.rom + Pico.romsize);
  56                 return 1;
  57         }
  58         else if ((source & 0xfe0000) == 0x300000)
  59         {
  60                 elprintf(EL_VDPDMA|EL_SVP, "SVP DmaSlow from %06x, len=%i", source, len);
  61                 source &= 0x1fffe;
  62                 source -= 2;
  63                 *srcp = (unsigned short *)(svp->dram + source);
  64                 *limitp = (unsigned short *)(svp->dram + sizeof(svp->dram));
  65                 return 1;
  66         }
  67         else
  68                 elprintf(EL_VDPDMA|EL_SVP|EL_ANOMALY, "SVP FIXME unhandled DmaSlow from %06x, len=%i", source, len);
  69
  70         return 0;
  71 }
  72
  73
  74 void PicoSVPInit(void)
  75 {
  76         void *tmp;
  77
  78         elprintf(EL_SVP, "SVP init");
  79
  80         tmp = realloc(Pico.rom, 0x200000 + sizeof(*svp));
  81         if (tmp == NULL)
  82         {
  83                 elprintf(EL_STATUS|EL_SVP, "OOM for SVP data");
  84                 return;
  85         }
  86
  87         Pico.rom = tmp;
  88         svp = (void *) ((char *)tmp + 0x200000);
  89         memset(svp, 0, sizeof(*svp));
  90
  91         // init ok, setup hooks..
  92         PicoRead16Hook = PicoSVPRead16;
  93         PicoWrite8Hook = PicoSVPWrite8;
  94         PicoWrite16Hook = PicoSVPWrite16;
  95         PicoDmaHook = PicoSVPDma;
  96         PicoResetHook = PicoSVPReset;
  97         PicoLineHook = PicoSVPLine;
  98
  99         // save state stuff
 100         svp_states[0].ptr = svp->iram_rom;
 101         svp_states[1].ptr = svp->dram;
 102         svp_states[2].ptr = &svp->ssp1601;
 103         carthw_chunks = svp_states;
 104 }
 105