Add mapper 474.

src/boards/474.c

@@ -0,0 +1,61 @@
+/* FCEUmm - NES/Famicom Emulator
+ *
+ * Copyright notice for this file:
+ *  Copyright (C) 2025 NewRisingSun
+ *
+ * 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 "mmc3.h"
+
+static void PRGWrap(uint32 A, uint8 V) {
+	if (EXPREGS[0] &0x04) {
+		setprg16(0x8000, EXPREGS[0] >>3 &0x1F | EXPREGS[0] <<5 &0x20);
+		setprg16(0xC000, EXPREGS[0] >>3 &0x1F | EXPREGS[0] <<5 &0x20);
+	} else
+		setprg32(0x8000, EXPREGS[0] >>4 &0x0F | EXPREGS[0] <<4 &0x10);
+}
+
+static void CHRWrap(uint32 A, uint8 V) {
+	setchr1(A, V &0xFF | EXPREGS[0] <<7 &0x100);
+}
+
+static DECLFW(WriteExtra) {
+	if (A &0x100) {
+		EXPREGS[0] =V;
+		FixMMC3PRG(MMC3_cmd);
+		FixMMC3CHR(MMC3_cmd);
+	}
+}
+
+static void Reset(void) {
+	EXPREGS[0] =0;
+	MMC3RegReset();
+}
+
+static void Power(void) {
+	EXPREGS[0] =0;
+	GenMMC3Power();
+	SetWriteHandler(0x4100, 0x5FFF, WriteExtra);
+}
+
+void Mapper474_Init(CartInfo *info) {
+	GenMMC3_Init(info, 128, 256, 0, 0);
+	cwrap = CHRWrap;
+	pwrap = PRGWrap;
+	info->Power = Power;
+	info->Reset = Reset;
+	AddExState(EXPREGS, 1, 0, "EXPR");
+}