Shamusworld >> Repos - virtualjaguar/blob - src/cdrom.cpp

   1 //
   2 // CD handler
   3 //
   4 // by cal2
   5 // GCC/SDL port by Niels Wagenaar (Linux/WIN32) and Caz (BeOS)
   6 // Cleanups by James L. Hammons
   7 //
   8
   9 #include "cdrom.h"
  10
  11 //#define CDROM_LOG
  12
  13 static uint8 cdrom_ram[0x100];
  14 static uint16 cdrom_cmd = 0;
  15
  16
  17 void cdrom_init(void)
  18 {
  19 }
  20
  21 void cdrom_reset(void)
  22 {
  23         memset(cdrom_ram, 0x00, 0x100);
  24         cdrom_cmd = 0;
  25 }
  26
  27 void cdrom_done(void)
  28 {
  29 }
  30
  31 //
  32 // CD-ROM memory access functions
  33 //
  34
  35 uint8 CDROMReadByte(uint32 offset, uint32 who/*=UNKNOWN*/)
  36 {
  37 #ifdef CDROM_LOG
  38         WriteLog("CDROM: reading byte from 0x%.8x\n",offset);
  39 #endif
  40         return cdrom_ram[offset & 0xFF];
  41 }
  42
  43 uint16 CDROMReadWord(uint32 offset, uint32 who/*=UNKNOWN*/)
  44 {
  45         offset &= 0xFF;
  46
  47         uint16 data = 0x0000;
  48
  49         if (offset == 0x00)
  50                 data = 0x0000;
  51         else if (offset == 0x02)
  52                 data = 0x2000;
  53         else if (offset == 0x0A)
  54         {
  55                 if (cdrom_cmd == 0x7001)
  56                         data = cdrom_cmd;
  57                 else
  58                         data = 0x0400;
  59         }
  60         else
  61                 data = (cdrom_ram[offset+0] << 8) | cdrom_ram[offset+1];
  62
  63 #ifdef CDROM_LOG
  64         WriteLog("CDROM: reading word 0x%.4x from 0x%.8x [68k pc=0x%.8x]\n",data,offset,s68000readPC());
  65 #endif
  66         return data;
  67 }
  68
  69 void CDROMWriteByte(uint32 offset, uint8 data, uint32 who/*=UNKNOWN*/)
  70 {
  71         offset &= 0xFF;
  72         cdrom_ram[offset] = data;
  73
  74 #ifdef CDROM_LOG
  75         WriteLog("CDROM: writing byte 0x%.2x at 0x%.8x\n",data,offset);
  76 #endif
  77 }
  78
  79 void CDROMWriteWord(uint32 offset, uint16 data, uint32 who/*=UNKNOWN*/)
  80 {
  81         offset &= 0xFF;
  82         cdrom_ram[offset+0] = (data >> 8) & 0xFF;
  83         cdrom_ram[offset+1] = data & 0xFF;
  84
  85         // command register
  86 /*
  87         if (offset==0x0A)
  88         {
  89                 cdrom_cmd=data;
  90                 if ((data&0xff00)==0x1500)
  91                 {
  92                         WriteLog("CDROM: setting mode 0x%.2x\n",data&0xff);
  93                         return;
  94                 }
  95                 if (data==0x7001)
  96                 {
  97                         uint32 offset=cdrom_ram[0x00];
  98                         offset<<=8;
  99                         offset|=cdrom_ram[0x01];
 100                         offset<<=8;
 101                         offset|=cdrom_ram[0x02];
 102                         offset<<=8;
 103                         offset|=cdrom_ram[0x03];
 104
 105                         uint32 size=cdrom_ram[0x04];
 106                         offset<<=8;
 107                         offset|=cdrom_ram[0x05];
 108
 109                         WriteLog("CDROM: READ(0x%.8x, 0x%.4x) [68k pc=0x%.8x]\n",offset,size,s68000readPC());
 110                         return;
 111                 }
 112                 else
 113                         WriteLog("CDROM: unknown command 0x%.4x\n",data);
 114         }
 115 */
 116 #ifdef CDROM_LOG
 117         WriteLog("CDROM: writing word 0x%.4x at 0x%.8x\n",data,offset);
 118 #endif
 119 }