fceugx/source/fceultra/boards/vrc7p.cpp

/* FCE Ultra - NES/Famicom Emulator
 *
 * Copyright notice for this file:
 *  Copyright (C) 2009 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
 *
 * YOKO Mortal Kombat V Pro, VRC7 pirate clone
 */

#include "mapinc.h"

static uint8 prg[3], chr[8], mirr;
static uint8 IRQLatch, IRQa, IRQd;
static int32 IRQCount, CycleCount;

static SFORMAT StateRegs[] =
{
	{ prg, 3, "PRG" },
	{ chr, 8, "CHR" },
	{ &mirr, 1, "MIRR" },
	{ &IRQa, 1, "IRQA" },
	{ &IRQd, 1, "IRQD" },
	{ &IRQLatch, 1, "IRQL" },
	{ &IRQCount, 4, "IRQC" },
	{ &CycleCount, 4, "CYCC" },
	{ 0 }
};

static void Sync(void) {
	uint8 i;
	setprg8(0x8000, prg[0]);
	setprg8(0xa000, prg[1]);
	setprg8(0xc000, prg[2]);
	setprg8(0xe000, ~0);
	for (i = 0; i < 8; i++)
		setchr1(i << 10, chr[i]);
	switch (mirr & 3) {
	case 0: setmirror(MI_V); break;
	case 1: setmirror(MI_H); break;
	case 2: setmirror(MI_0); break;
	case 3: setmirror(MI_1); break;
	}
}

static DECLFW(UNLVRC7Write) {
	switch (A & 0xF008) {
	case 0x8000: prg[0] = V; Sync(); break;
	case 0x8008: prg[1] = V; Sync(); break;
	case 0x9000: prg[2] = V; Sync(); break;
	case 0xa000: chr[0] = V; Sync(); break;
	case 0xa008: chr[1] = V; Sync(); break;
	case 0xb000: chr[2] = V; Sync(); break;
	case 0xb008: chr[3] = V; Sync(); break;
	case 0xc000: chr[4] = V; Sync(); break;
	case 0xc008: chr[5] = V; Sync(); break;
	case 0xd000: chr[6] = V; Sync(); break;
	case 0xd008: chr[7] = V; Sync(); break;
	case 0xe000: mirr = V; Sync(); break;
	case 0xe008: IRQLatch = V; X6502_IRQEnd(FCEU_IQEXT); break;
	case 0xf000:
		IRQa = V & 2;
		IRQd = V & 1;
		if (V & 2)
			IRQCount = IRQLatch;
		CycleCount = 0;
		X6502_IRQEnd(FCEU_IQEXT);
		break;
	case 0xf008:
		if (IRQd)
			IRQa = 1;
		else
			IRQa = 0;
		X6502_IRQEnd(FCEU_IQEXT);
		break;
	}
}

static void UNLVRC7Power(void) {
	Sync();
	SetReadHandler(0x8000, 0xFFFF, CartBR);
	SetWriteHandler(0x8000, 0xFFFF, UNLVRC7Write);
}

static void UNLVRC7IRQHook(int a) {
	if (IRQa) {
		CycleCount += a * 3;
		while (CycleCount >= 341) {
			CycleCount -= 341;
			IRQCount++;
			if (IRQCount == 248) {
				IRQCount = IRQLatch;
				X6502_IRQBegin(FCEU_IQEXT);
			}
		}
	}
}

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

void UNLVRC7_Init(CartInfo *info) {
	info->Power = UNLVRC7Power;
	MapIRQHook = UNLVRC7IRQHook;
	GameStateRestore = StateRestore;
	AddExState(&StateRegs, ~0, 0, 0);
}