ci-libretro-fceumm/src/boards/116.c

/* FCE Ultra - NES/Famicom Emulator
 *
 * Copyright notice for this file:
 *  Copyright (C) 2023
 *
 * 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"
#include "asic_mmc1.h"
#include "asic_mmc3.h"
#include "asic_vrc2and4.h"

static uint8 submapper;
static uint8 reg;
static uint8 init; /* Games switch between ASICs expecting registers to keep their value, so initialize each ASIC only on the first switch and use this bitfield to track it */
static uint8 game;

static SFORMAT stateRegs[] = {
	{ &reg, 1, "MODE" },
	{ &init, 1, "INIT" },
	{ 0 },
};

static SFORMAT stateRegsMulti[] = {
	{ &game, 1, "GAME" },
	{ 0 },
};

static void sync (void) {
	int prgAND, chrAND, prgOR, chrOR;
	if (submapper == 3) { /* First game is 256K+256K, the others 128K+128K */
		prgAND = game? 0x0F: 0x1F;
		chrAND = game? 0x7F: 0xFF;
		prgOR  = game <<4 &~prgAND;
		chrOR  = game <<7 &~chrAND;
	} else {
		prgAND = 0x3F;
		chrAND = 0xFF;
		prgOR  = 0x00 &~prgAND;
		chrOR  = reg <<6 &0x100 &~chrAND;
	}
	if (reg &0x02) {
		prgAND >>= 1;
		prgOR >>= 1;
		chrAND >>= 2;
		chrOR >>= 2;
		MMC1_syncPRG(prgAND, prgOR);
		MMC1_syncCHR(chrAND, chrOR);
		MMC1_syncMirror();
	} else
	if (reg &0x01) {
		MMC3_syncPRG(prgAND, prgOR);
		MMC3_syncCHR(chrAND, chrOR);
		MMC3_syncMirror();
	} else {
		VRC24_syncPRG(prgAND, prgOR);
		VRC24_syncCHR(chrAND, chrOR);
		VRC24_syncMirror();
	}
}

int Huang2_getPRGBank (uint8 bank) {
	return MMC1_getPRGBank(bank) >>1;
}

static void applyMode (uint8 clear) {
	PPU_hook = NULL;
	MapIRQHook = NULL;
	GameHBIRQHook = NULL;
	if (reg &0x02) {
		MMC1_activate(clear && init &1, sync, MMC1_TYPE_MMC1B, submapper == 2? Huang2_getPRGBank: NULL, NULL, NULL, NULL);
		if (submapper != 1) MMC1_writeReg(0x8000, 0x80);
		init &= ~1;
	} else
	if (reg &0x01) {
		MMC3_activate(clear && init &2, sync, MMC3_TYPE_AX5202P, NULL, NULL, NULL, NULL);
		init &= ~2;
	} else {
		VRC2_activate(clear && init &4, sync, 0x01, 0x02, NULL, NULL, NULL, NULL);
		if (init &4) { /* The earlier version of Somari needs specific VRC2 CHR register initialization */
			VRC24_writeReg(0xB000, 0xFF); VRC24_writeReg(0xB001, 0xFF); VRC24_writeReg(0xB002, 0xFF); VRC24_writeReg(0xB003, 0xFF);
			VRC24_writeReg(0xC000, 0xFF); VRC24_writeReg(0xC001, 0xFF); VRC24_writeReg(0xC002, 0xFF); VRC24_writeReg(0xC003, 0xFF);
			VRC24_writeReg(0xD000, 0xFF); VRC24_writeReg(0xD001, 0xFF); VRC24_writeReg(0xD002, 0xFF); VRC24_writeReg(0xD003, 0xFF);
			VRC24_writeReg(0xE000, 0xFF); VRC24_writeReg(0xE001, 0xFF); VRC24_writeReg(0xE002, 0xFF); VRC24_writeReg(0xE003, 0xFF);
			init &= ~4;
		}
	}
}

static DECLFW (writeReg) {
	if (A &0x100) {
		uint8 previousReg = reg;
		reg = V;
		if ((previousReg ^V) &3)
			applyMode(1);
		else
			sync();
	}
}

static void reset (void) {
	reg = 1;
	init = 7;
	if (++game == 1) ++game; /* First game is twice as large */
	if (game >= ROM_size /8) game = 0;
	applyMode(1);
}

static void power (void) {
	reg = 1;
	init = 7;
	game = 0;
	SetReadHandler(0x8000, 0xFFFF, CartBR);
	SetWriteHandler(0x4020, 0x5FFF, writeReg);
	applyMode(1);
}

static void restore (int version) {
	applyMode(0);
}

void UNLSL12_Init (CartInfo *info) {
	submapper = info->submapper;
	MMC1_addExState();
	MMC3_addExState();
	VRC24_addExState();
	info->Reset = reset;
	info->Power = power;
	GameStateRestore = restore;
	AddExState(stateRegs, ~0, 0, 0);
	if (submapper == 3) AddExState(stateRegsMulti, ~0, 0, 0);
}