mappers/189.c

   1 /* Is this an MMC3 workalike piece of hardware, with the addition of
   2    a register at $4120 or does it have only partial MMC3 functionality?
   3    A good test would be to see if commands 6 and 7 can change PRG banks
   4    and of course test the regs >=$c000, on the real cart.
   5 */
   6 #include "mapinc.h"
   7
   8 #define cmd mapbyte1[0]
   9 static DECLFW(Mapper189_write)
  10 {
  11  //if(A>=0xc000) printf("$%04x:$%02x\n",A,V);
  12  if((A&0xF100)==0x4100) ROM_BANK32(V>>4);
  13  else if((A&0xF100)==0x6100) ROM_BANK32(V&3);
  14  else switch(A&0xE001)
  15  {
  16   case 0xa000:MIRROR_SET(V&1);break;
  17   case 0x8000:cmd=V;break;
  18   case 0x8001:switch(cmd&7)
  19               {
  20                case 0:VROM_BANK2(0x0000,V>>1);break;
  21                case 1:VROM_BANK2(0x0800,V>>1);break;
  22                case 2:VROM_BANK1(0x1000,V);break;
  23                case 3:VROM_BANK1(0x1400,V);break;
  24                case 4:VROM_BANK1(0x1800,V);break;
  25                case 5:VROM_BANK1(0x1C00,V);break;
  26               }
  27    case 0xc000:IRQLatch=V;break;
  28    case 0xc001:IRQCount=IRQLatch;break;
  29    case 0xe000:IRQa=0;X6502_IRQEnd(FCEU_IQEXT);break;
  30    case 0xe001:IRQa=1;break;
  31               break;
  32
  33  }
  34 }
  35 void m189irq(void)
  36 {
  37  if(IRQa)
  38  {
  39   if(IRQCount)
  40   {
  41    IRQCount--;
  42    if(!IRQCount) X6502_IRQBegin(FCEU_IQEXT);
  43   }
  44  }
  45
  46 }
  47 void Mapper189_init(void)
  48 {
  49   GameHBIRQHook=m189irq;
  50   SetWriteHandler(0x4120,0xFFFF,Mapper189_write);
  51   SetReadHandler(0x6000,0x7FFF,0);
  52   ROM_BANK32(0);
  53 }
  54
  55