mappers/248.c

   1 /* FCE Ultra - NES/Famicom Emulator
   2  *
   3  * Copyright notice for this file:
   4  *  Copyright (C) 2002 Ben Parnell
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  19  */
  20
  21 #include "mapinc.h"
  22
  23 #define cmd mapbyte1[0]
  24 #define lpa mapbyte1[1]
  25 #define prgl mapbyte2
  26
  27 static void PRGSynco(void)
  28 {
  29  if(lpa&0x80)
  30  {
  31   ROM_BANK16(0x8000,lpa&0xF);
  32  }
  33  else
  34  {
  35   ROM_BANK8(0x8000,prgl[0]&0x1F);
  36   ROM_BANK8(0xa000,prgl[1]&0x1F);
  37  }
  38  X6502_Rebase();
  39 }
  40
  41 static DECLFW(Mapper248_writelow)
  42 {
  43  lpa=V;
  44  PRGSynco();
  45 }
  46
  47 static DECLFW(Mapper248_write)
  48 {
  49  switch(A&0xF001)
  50  {
  51   case 0xa000:MIRROR_SET(V&1);break; // Not sure if this is right.  Mirroring may be hard wired...
  52   case 0xc000:IRQLatch=V;break;
  53   case 0xc001:IRQCount=IRQLatch;break;
  54   case 0xe000:IRQa=0;X6502_IRQEnd(FCEU_IQEXT);break;
  55   case 0xe001:IRQa=1;break;
  56   case 0x8000:cmd=V;break;
  57   case 0x8001:switch(cmd&7)
  58               {
  59                case 0:VROM_BANK2(0x000,V>>1);break;
  60                case 1:VROM_BANK2(0x800,V>>1);break;
  61                case 2:VROM_BANK1(0x1000,V);break;
  62                case 3:VROM_BANK1(0x1400,V);break;
  63                case 4:VROM_BANK1(0x1800,V);break;
  64                case 5:VROM_BANK1(0x1c00,V);break;
  65                case 6:prgl[0]=V;PRGSynco();break;
  66                case 7:prgl[1]=V;PRGSynco();break;
  67               }
  68               break;
  69  }
  70 }
  71
  72 static void Mapper248_hb(void)
  73 {
  74  if(IRQa)
  75  {
  76          IRQCount--;
  77          if(IRQCount<0)
  78          {
  79           X6502_IRQBegin(FCEU_IQEXT);
  80           IRQCount=IRQLatch;
  81          }
  82  }
  83 }
  84
  85 void Mapper248_init(void)
  86 {
  87   SetWriteHandler(0x6000,0x6fff,Mapper248_writelow);
  88   SetWriteHandler(0x8000,0xffff,Mapper248_write);
  89   GameHBIRQHook=Mapper248_hb;
  90 }
  91