save.cpp

   1 // DGen v1.10+
   2 // Megadrive C++ module saving and loading
   3
   4 #include <stdio.h>
   5 #include <string.h>
   6 #include "md.h"
   7
   8 /*
   9 gs0 genecyst save file INfo
  10
  11 GST\0 to start with
  12
  13 80-9f = d0-d7 almost certain
  14 a0-bf = a0-a7 almost certain
  15 c8    = pc    fairly certain
  16 d0    = sr    fairly certain
  17
  18
  19 112 Start of cram len 0x80
  20 192 Start of vsram len 0x50
  21 1e2-474 UNKNOWN sound info?
  22 Start of z80 ram at 474 (they store 2000)
  23 Start of RAM at 2478 almost certain (BYTE SWAPPED)
  24 Start of VRAM at 12478
  25 end of VRAM
  26 */
  27
  28 // NB - for load and save you don't need to use star_mz80_on/off
  29 // Because stars/mz80 isn't actually used
  30 #define fput(x,y) { if (fwrite(x,1,y,hand)!=y) goto save_error; }
  31 #define fget(x,y) if (fread(x,1,y,hand)!=y) goto load_error;
  32
  33 extern int byteswap_memory(unsigned char *start,int len);
  34
  35 int md::import_gst(FILE *hand)
  36 {
  37 #ifdef COMPILE_WITH_STAR
  38   if (cpu_emu==0)
  39   {
  40     fseek(hand,0x80,SEEK_SET);
  41     fget(cpu.dreg,8*4);
  42     fget(cpu.areg,8*4);
  43     fseek(hand,0xc8,SEEK_SET);
  44     fget(&cpu.pc,4);
  45     fseek(hand,0xd0,SEEK_SET);
  46     fget(&cpu.sr,4);
  47   }
  48 #endif
  49
  50 #ifdef COMPILE_WITH_MUSA
  51   if (cpu_emu==1)
  52   {
  53     int i,t;
  54     fseek(hand,0x80,SEEK_SET);
  55     for (i=0;i<8;i++)
  56     { fget(&t,4); m68k_poke_dr(i,t); }
  57     for (i=0;i<8;i++)
  58     { fget(&t,4); m68k_poke_ar(i,t); }
  59
  60     fseek(hand,0xc8,SEEK_SET);
  61     fget(&t,4); m68k_poke_pc(t);
  62
  63     fseek(hand,0xd0,SEEK_SET);
  64     fget(&t,4); m68k_poke_sr(t);
  65   }
  66 #endif
  67
  68   fseek(hand,0xfa,SEEK_SET);
  69   fget(vdp.reg,0x18);
  70
  71   fseek(hand,0x112,SEEK_SET);
  72   fget(vdp.cram ,0x00080);
  73   byteswap_memory(vdp.cram,0x80);
  74   fget(vdp.vsram,0x00050);
  75   byteswap_memory(vdp.vsram,0x50);
  76
  77   fseek(hand,0x474,SEEK_SET);
  78   fget(z80ram,   0x02000);
  79
  80   fseek(hand,0x2478,SEEK_SET);
  81   fget(ram,      0x10000);
  82   byteswap_memory(ram,0x10000);
  83
  84   fget(vdp.vram ,0x10000);
  85
  86   memset(vdp.dirt,0xff,0x35); // mark everything as changed
  87
  88   return 0;
  89 load_error:
  90   return 1;
  91 }
  92
  93
  94 int md::export_gst(FILE *hand)
  95 {
  96   int i;
  97   static unsigned char gst_head[0x80]=
  98   {
  99        0x47,0x53,0x54,0,0,0,0xe0,0x40
 100
 101   //     00 00 00 00 00 00 00 00 00 00 00 00 00 21 80 fa   <.............!..>
 102   };
 103   unsigned char *zeros=gst_head+0x40; // 0x40 zeros
 104
 105   fseek(hand,0x00,SEEK_SET);
 106   // Make file size 0x22478 with zeros
 107   for (i=0;i<0x22440;i+=0x40) fput(zeros,0x40);
 108   fput(zeros,0x38);
 109
 110   fseek(hand,0x00,SEEK_SET);
 111   fput(gst_head,0x80);
 112
 113 #ifdef COMPILE_WITH_STAR
 114   if (cpu_emu==0)
 115   {
 116     fseek(hand,0x80,SEEK_SET);
 117     fput(cpu.dreg,8*4);
 118     fput(cpu.areg,8*4);
 119     fseek(hand,0xc8,SEEK_SET);
 120     fput(&cpu.pc,4);
 121     fseek(hand,0xd0,SEEK_SET);
 122     fput(&cpu.sr,4);
 123   }
 124 #endif
 125 #ifdef COMPILE_WITH_MUSA
 126   if (cpu_emu==1)
 127   {
 128     int i,t;
 129     fseek(hand,0x80,SEEK_SET);
 130     for (i=0;i<8;i++)
 131     { t=m68k_peek_dr(i); fput(&t,4);}
 132     for (i=0;i<8;i++)
 133     { t=m68k_peek_ar(i); fput(&t,4);}
 134
 135     fseek(hand,0xc8,SEEK_SET);
 136     t=m68k_peek_pc(); fput(&t,4);
 137
 138     fseek(hand,0xd0,SEEK_SET);
 139     t=m68k_peek_sr(); fput(&t,4);
 140   }
 141 #endif
 142
 143   fseek(hand,0xfa,SEEK_SET);
 144   fput(vdp.reg,0x18);
 145
 146   fseek(hand,0x112,SEEK_SET);
 147   byteswap_memory(vdp.cram,0x80);
 148   fput(vdp.cram ,0x00080);
 149   byteswap_memory(vdp.cram,0x80);
 150   byteswap_memory(vdp.vsram,0x50);
 151   fput(vdp.vsram,0x00050);
 152   byteswap_memory(vdp.vsram,0x50);
 153
 154   fseek(hand,0x474,SEEK_SET);
 155   fput(z80ram,   0x02000);
 156
 157   fseek(hand,0x2478,SEEK_SET);
 158   byteswap_memory(ram,0x10000);
 159   fput(ram,      0x10000);
 160   byteswap_memory(ram,0x10000);
 161
 162   fput(vdp.vram ,0x10000);
 163
 164   return 0;
 165 save_error:
 166   return 1;
 167 }
 168