/* FCE Ultra - NES/Famicom Emulator
 *
 * Copyright notice for this file:
 *  Copyright (C) 2005 CaH4e3
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 * Lethal Weapon (VRC4 mapper)
 */

#include "mapinc.h"

static uint8 prg0, prg1, mirr, swap;
static uint8 chr[8];
static uint8 IRQCount;           
static uint8 IRQPre;
static uint8 IRQa;

static SFORMAT StateRegs[]=
{
  {&prg0, 1, "PRG0"},
  {&prg0, 1, "PRG1"},
  {&mirr, 1, "MIRR"},
  {&swap, 1, "SWAP"},
  {chr, 8, "CHR"},
  {&IRQCount, 1, "IRQCOUNT"},
  {&IRQPre, 1, "IRQPRE"},
  {&IRQa, 1, "IRQA"},
  {0}
};

static void SyncPrg(void)
{
  if(swap&3)
  {
    setprg8(0x8000,~1);
    setprg8(0xC000,prg0);
  }  
  else
  {
    setprg8(0x8000,prg0);
    setprg8(0xC000,~1);
  }
  setprg8(0xA000,prg1);
  setprg8(0xE000,~0);
}

static void SyncChr(void)
{
  int i;
  for(i=0; i<8; i++)
     setchr1(i<<10,chr[i]);
  setmirror(mirr^1);
}

static void StateRestore(int version)
{
  SyncPrg();
  SyncChr();
}

static DECLFW(UNLTF1201Write)
{
  A=(A&0xF003)|((A&0xC)>>2);
  if((A>=0xB000)&&(A<=0xE003))
  {
    int ind=(((A>>11)-6)|(A&1))&7;
    int sar=((A&2)<<1);
    chr[ind]=(chr[ind]&(0xF0>>sar))|((V&0x0F)<<sar);
    SyncChr();
  }
  else switch (A&0xF003)
  {
    case 0x8000: prg0=V; SyncPrg(); break;
    case 0xA000: prg1=V; SyncPrg(); break;
    case 0x9000: mirr=V&1; SyncChr(); break;
    case 0x9001: swap=V&3; SyncPrg(); break;
    case 0xF000: IRQCount=((IRQCount&0xF0)|(V&0xF)); break;
    case 0xF002: IRQCount=((IRQCount&0x0F)|((V&0xF)<<4)); break;
    case 0xF001: 
    case 0xF003: IRQa=V&2; X6502_IRQEnd(FCEU_IQEXT); if(scanline<240) IRQCount-=8; break;
  }
}
  
static void UNLTF1201IRQCounter(void)
{
  if(IRQa)
  {
    IRQCount++;
    if(IRQCount==237)
    {
      X6502_IRQBegin(FCEU_IQEXT);
    }
  }
}
  
static void UNLTF1201Power(void)
{
  IRQPre=IRQCount=IRQa=0;
  SetReadHandler(0x8000,0xFFFF,CartBR);
  SetWriteHandler(0x8000,0xFFFF,UNLTF1201Write);
  SyncPrg();
  SyncChr();
}

void UNLTF1201_Init(CartInfo *info)
{
  info->Power=UNLTF1201Power;
  GameHBIRQHook=UNLTF1201IRQCounter;
  GameStateRestore=StateRestore;
  AddExState(&StateRegs, ~0, 0, 0);
}