/* FCE Ultra - NES/Famicom Emulator
 *
 * Copyright notice for this file:
 *  Copyright (C) 2015 CaH4e3
 *  Copyright (C) 2020 dragon2snow,loong2snow from www.nesbbs.com
 * 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 uint8 regs[2];
static uint8 _submapper = 0;

static SFORMAT StateRegs[] =
{
	{ regs, 2, "REGS" },
	{ &_submapper ,1, "SUBM"},
	{ 0 }
};

/* submapper 1 The code for the original fceux
 * submapper 0 new HP898F code by dragon2snow,loong2snow from www.nesbbs.com 
 */
static void Sync(void) {
	
	if (_submapper == 1)
	{
		uint8 chr = (regs[0] >> 4) & 7;
		uint8 prg = (regs[1] >> 3) & 7;
		uint8 dec = (regs[1] >> 4) & 4;
		setchr8(chr & (~(((regs[0] & 1) << 2) | (regs[0] & 2))));
		setprg16(0x8000, prg & (~dec));
		setprg16(0xC000, prg | dec);
		setmirror(regs[1] >> 7);
	}
	else
	{
		if (regs[1] & 0x40)
			setprg32(0x8000, regs[1] >> 1);
		else {
			setprg16(0x8000, regs[1]);
			setprg16(0xC000, regs[1]);
		}
		setchr8((regs[0] >> 4) &~(((regs[0] & 1) ? 4 : 0) | (regs[0] & 2)));
		if (regs[1] & 0x80)
			setmirror(1);
		else
			setmirror(0);
	}
}

static DECLFW(HP898FWrite) {
	if((A & 0x6000) == 0x6000) {
		regs[(A & 4) >> 2] = V;
		Sync();
	}
}

static DECLFW(HP898FWriteEx) {
	switch (A & 4) {
	case 0:	regs[0] = V; break; /* CHR */
	case 4:	regs[1] = (V & 0xC0) | ((V >> 2) & 6) | ((V & 0x20) ? 1 : 0); break; /* PRG */
	}
	Sync();
}
static void HP898FPower(void) {
	regs[0] = regs[1] = 0;
	Sync();
	if (_submapper == 1)
	{
		SetReadHandler(0x8000, 0xFFFF, CartBR);
		SetWriteHandler(0x6000, 0xFFFF, HP898FWrite);
	}
	else
	{
		SetReadHandler(0x8000, 0xFFFF, CartBR);
		SetWriteHandler(0x6000, 0x7FFF, HP898FWriteEx);
		SetWriteHandler(0xE000, 0xFFFF, HP898FWriteEx);
	}
}

static void HP898FReset(void) {
	regs[0] = regs[1] = 0;
	Sync();
}

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

void BMCHP898F_Init(CartInfo *info) {
	_submapper = info->submapper;
	info->Reset = HP898FReset;
	info->Power = HP898FPower;
	GameStateRestore = StateRestore;
	AddExState(&StateRegs, ~0, 0, 0);
}