/* 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
 */

#include "mapinc.h"

static uint16 cmdreg;
static uint8 invalid_data;
static SFORMAT StateRegs[]=
{
  {&invalid_data, 1, "INVD"},  
  {&cmdreg, 2, "CMDREG"},
  {0}
};

static void Sync(void)
{
  setprg16r((cmdreg&0x060)>>5,0x8000,(cmdreg&0x01C)>>2);
  setprg16r((cmdreg&0x060)>>5,0xC000,(cmdreg&0x200)?(~0):0);
  setmirror(((cmdreg&2)>>1)^1);
}

static DECLFR(UNL8157Read)
{
  if(invalid_data&&cmdreg&0x100)
    return 0xFF;
  else
    return CartBR(A);
}

static DECLFW(UNL8157Write)
{
  cmdreg=A;
  Sync();
}

static void UNL8157Power(void)
{
  setchr8(0);
  SetWriteHandler(0x8000,0xFFFF,UNL8157Write);
  SetReadHandler(0x8000,0xFFFF,UNL8157Read);
  cmdreg=0x200;
  invalid_data=1;
  Sync();
}

static void UNL8157Reset(void)
{
  cmdreg=0;
  invalid_data^=1;
  Sync();
}

static void UNL8157Restore(int version)
{
  Sync();
}

void UNL8157_Init(CartInfo *info)
{
  info->Power=UNL8157Power;
  info->Reset=UNL8157Reset;
  GameStateRestore=UNL8157Restore;
  AddExState(&StateRegs, ~0, 0, 0);
}