fceugx/source/fceultra/boards/222.cpp

/* 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., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 *
 * (VRC4 mapper)
 *
 */

#include "mapinc.h"

static uint8 IRQCount;
static uint8 IRQa;
static uint8 prg_reg[2];
static uint8 chr_reg[8];
static uint8 mirr;

static SFORMAT StateRegs[] =
{
	{ &IRQCount, 1, "IRQC" },
	{ &IRQa, 1, "IRQA" },
	{ prg_reg, 2, "PRG" },
	{ chr_reg, 8, "CHR" },
	{ &mirr, 1, "MIRR" },
	{ 0 }
};

static void M222IRQ(void) {
	if (IRQa) {
		IRQCount++;
		if (IRQCount >= 238) {
			X6502_IRQBegin(FCEU_IQEXT);
//			IRQa=0;
		}
	}
}

static void Sync(void) {
	setprg8(0x8000, prg_reg[0]);
	setprg8(0xA000, prg_reg[1]);
	int i;
	for (i = 0; i < 8; i++)
		setchr1(i << 10, chr_reg[i]);
	setmirror(mirr ^ 1);
}

static DECLFW(M222Write) {
	switch (A & 0xF003) {
	case 0x8000: prg_reg[0] = V; break;
	case 0x9000: mirr = V & 1; break;
	case 0xA000: prg_reg[1] = V; break;
	case 0xB000: chr_reg[0] = V; break;
	case 0xB002: chr_reg[1] = V; break;
	case 0xC000: chr_reg[2] = V; break;
	case 0xC002: chr_reg[3] = V; break;
	case 0xD000: chr_reg[4] = V; break;
	case 0xD002: chr_reg[5] = V; break;
	case 0xE000: chr_reg[6] = V; break;
	case 0xE002: chr_reg[7] = V; break;
//	case 0xF000: FCEU_printf("%04x:%02x %d\n",A,V,scanline); IRQa=V; if(!V)IRQPre=0; X6502_IRQEnd(FCEU_IQEXT); break;
//	case 0xF001: FCEU_printf("%04x:%02x %d\n",A,V,scanline); IRQCount=V; break;
//	case 0xF002: FCEU_printf("%04x:%02x %d\n",A,V,scanline); break;
//	case 0xD001: IRQa=V; X6502_IRQEnd(FCEU_IQEXT); FCEU_printf("%04x:%02x %d\n",A,V,scanline); break;
//	case 0xC001: IRQPre=16; FCEU_printf("%04x:%02x %d\n",A,V,scanline); break;
	case 0xF000: IRQa = IRQCount = V; if (scanline < 240) IRQCount -= 8; else IRQCount += 4; X6502_IRQEnd(FCEU_IQEXT); break;
	}
	Sync();
}

static void M222Power(void) {
	setprg16(0xC000, ~0);
	SetReadHandler(0x8000, 0xFFFF, CartBR);
	SetWriteHandler(0x8000, 0xFFFF, M222Write);
}

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

void Mapper222_Init(CartInfo *info) {
	info->Power = M222Power;
	GameHBIRQHook = M222IRQ;
	GameStateRestore = StateRestore;
	AddExState(&StateRegs, ~0, 0, 0);
}