/* FCE Ultra - NES/Famicom Emulator
 *
 * Copyright notice for this file:
 *  Copyright (C) 2006 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., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 *
 */

#include "mapinc.h"

static uint16 latchea;
static uint8 latched;
static uint8 *WRAM = NULL;
static uint32 WRAMSIZE;
static SFORMAT StateRegs[] =
{
	{ &latchea, 2 | FCEUSTATE_RLSB, "AREG" },
	{ &latched, 1, "DREG" },
	{ 0 }
};

static void Sync(void) {
	uint32 preg[4];
	uint32 bank = (latched & 0x3F) << 1;
	switch (latchea & 0x03) {
	case 0:
		preg[0] = bank + 0;
		preg[1] = bank + 1;
		preg[2] = bank + 2;
		preg[3] = bank + 3;
		break;
	case 2:
		bank = bank | (latched >> 7);
		preg[0] = bank;
		preg[1] = bank;
		preg[2] = bank;
		preg[3] = bank;
		break;
	case 1:
	case 3:
		preg[0] = bank + 0;
		preg[1] = bank + 1;
		preg[2] = (((latchea & 0x02) == 0) ? (bank | 0xE) : bank) + 0;
		preg[3] = (((latchea & 0x02) == 0) ? (bank | 0xE) : bank) + 1;
		break;
	}

	setprg8(0x8000, preg[0]);
	setprg8(0xA000, preg[1]);
	setprg8(0xC000, preg[2]);
	setprg8(0xE000, preg[3]);
	setmirror(((latched >> 6) & 1) ^ 1);
}

static DECLFW(M15Write) {
	latchea = A;
	latched = V;
	Sync();
}

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

static void M15Power(void) {
	latchea = 0x8000;
	latched = 0;
	setchr8(0);
	setprg8r(0x10, 0x6000, 0);
	SetReadHandler(0x6000, 0x7FFF, CartBR);
	SetWriteHandler(0x6000, 0x7FFF, CartBW);
	SetWriteHandler(0x8000, 0xFFFF, M15Write);
	SetReadHandler(0x8000, 0xFFFF, CartBR);
    FCEU_CheatAddRAM(WRAMSIZE >> 10, 0x6000, WRAM);
	Sync();
}

static void M15Reset(void) {
	latchea = 0x8000;
	latched = 0;
	Sync();
}

static void M15Close(void) {
	if (WRAM)
		FCEU_gfree(WRAM);
	WRAM = NULL;
}

void Mapper15_Init(CartInfo *info) {
	info->Power = M15Power;
	info->Reset = M15Reset;
	info->Close = M15Close;
	GameStateRestore = StateRestore;
	WRAMSIZE = 8192;
	WRAM = (uint8*)FCEU_gmalloc(WRAMSIZE);
	SetupCartPRGMapping(0x10, WRAM, WRAMSIZE, 1);
	if (info->battery) {
		info->SaveGame[0] = WRAM;
		info->SaveGameLen[0] = WRAMSIZE;
	}
	AddExState(WRAM, WRAMSIZE, 0, "WRAM");
	AddExState(&StateRegs, ~0, 0, 0);
}