ci-libretro-fceumm/src/boards/454.c

/* FCEUmm - NES/Famicom Emulator
 *
 * Copyright notice for this file:
 *  Copyright (C) 2023-2024 negativeExponent
 *
 * 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 "latch.h"

static void Sync(void) {
	uint8 prg = ((latch.addr >> 3) & 0x20) | ((latch.addr >> 2) & 0x1F);
	uint8 cpuA14 = latch.addr & 0x01;
	uint8 nrom = (latch.addr >> 7) & 0x01;
	uint8 unrom = (latch.addr >> 8) & 0x01;

	setprg16(0x8000, ((prg & ~cpuA14) & ~(0x07 * unrom)) | (latch.data * unrom));
	setprg16(0xC000, ((prg | cpuA14) & ~(0x1F * !nrom * !unrom)) | (0x07 * unrom));
	SetupCartCHRMapping(0, CHRptr[0], 0x2000, latch.addr &0x80? 0: 1);
	setchr8(0);
	setmirror(((latch.addr >> 1) & 0x01) ^ 0x01);
}

static DECLFW(M454Write) {
	if (latch.addr & 0x100) {
		latch.data = V & 0x07;
	} else {
		latch.data = V;
		latch.addr = A;
	}
	Sync();
}

static void M454Power(void) {
	LatchPower();
	SetWriteHandler(0x8000, 0xFFFF, M454Write);
}

static void M454Reset(void) {
	latch.addr = 0;
	latch.data = 0;
	Sync();
}

void Mapper454_Init(CartInfo *info) {
	Latch_Init(info, Sync, NULL, 0, 0);
	info->Power = M454Power;
	info->Reset = M454Reset;
}