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 void cdrom_byte_write(uint32 offset, uint8 data)
  32 {
  33         offset &= 0xFF;
  34         cdrom_ram[offset] = data;
  35
  36 #ifdef CDROM_LOG
  37         fprintf(log_get(),"cdrom: writing byte 0x%.2x at 0x%.8x\n",data,offset);
  38 #endif
  39 }
  40
  41 void cdrom_word_write(uint32 offset, uint16 data)
  42 {
  43         offset &= 0xFF;
  44         cdrom_ram[offset+0] = (data >> 8) & 0xFF;
  45         cdrom_ram[offset+1] = data & 0xFF;
  46
  47         // command register
  48 /*
  49         if (offset==0x0A)
  50         {
  51                 cdrom_cmd=data;
  52                 if ((data&0xff00)==0x1500)
  53                 {
  54                         fprintf(log_get(),"cdrom: setting mode 0x%.2x\n",data&0xff);
  55                         return;
  56                 }
  57                 if (data==0x7001)
  58                 {
  59                         uint32 offset=cdrom_ram[0x00];
  60                         offset<<=8;
  61                         offset|=cdrom_ram[0x01];
  62                         offset<<=8;
  63                         offset|=cdrom_ram[0x02];
  64                         offset<<=8;
  65                         offset|=cdrom_ram[0x03];
  66
  67                         uint32 size=cdrom_ram[0x04];
  68                         offset<<=8;
  69                         offset|=cdrom_ram[0x05];
  70
  71                         fprintf(log_get(),"cdrom: READ(0x%.8x, 0x%.4x) [68k pc=0x%.8x]\n",offset,size,s68000readPC());
  72                         return;
  73                 }
  74                 else
  75                         fprintf(log_get(),"cdrom: unknown command 0x%.4x\n",data);
  76         }
  77 */
  78 #ifdef CDROM_LOG
  79         fprintf(log_get(),"cdrom: writing word 0x%.4x at 0x%.8x\n",data,offset);
  80 #endif
  81 }
  82
  83 uint8 cdrom_byte_read(uint32 offset)
  84 {
  85 #ifdef CDROM_LOG
  86         fprintf(log_get(),"cdrom: reading byte from 0x%.8x\n",offset);
  87 #endif
  88         return cdrom_ram[offset & 0xFF];
  89 }
  90
  91 uint16 cdrom_word_read(uint32 offset)
  92 {
  93         offset &= 0xFF;
  94
  95         uint16 data = 0x0000;
  96
  97         if (offset == 0x00)
  98                 data = 0x0000;
  99         else if (offset == 0x02)
 100                 data = 0x2000;
 101         else if (offset == 0x0A)
 102         {
 103                 if (cdrom_cmd == 0x7001)
 104                         data = cdrom_cmd;
 105                 else
 106                         data = 0x0400;
 107         }
 108         else
 109                 data = (cdrom_ram[offset+0] << 8) | cdrom_ram[offset+1];
 110
 111 #ifdef CDROM_LOG
 112         fprintf(log_get(),"cdrom: reading word 0x%.4x from 0x%.8x [68k pc=0x%.8x]\n",data,offset,s68000readPC());
 113 #endif
 114         return data;
 115 }