Add mapper 406, together with generic self-flashing code.

src/boards/406.c

@@ -0,0 +1,55 @@
+/* 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"
+#include "flashrom.h"
+
+uint8 submapper;
+
+static DECLFW(Write) {
+	flashrom_write(A &0x1FFF | (Page[A >>11] +A -PRGptr[0]) &~0x1FFF, V);
+
+	if (submapper ==1)
+		A =A <0xA000 || A >=0xE000? (A ^0x6000): A;
+	else
+		A =A &0xE000 | A >>1 &0x0001;
+	
+	if (A &0x4000)
+		MMC3_IRQWrite(A, V);
+	else
+		MMC3_CMDWrite(A, V);
+}
+
+static void Power(void) {
+	GenMMC3Power();
+	SetReadHandler(0x8000, 0xFFFF, flashrom_read);
+	SetWriteHandler(0x8000, 0xFFFF, Write);
+}
+
+void Mapper406_Init(CartInfo *info) {
+	submapper =info->submapper;
+	GenMMC3_Init(info, 512, 256, 0, 0);
+	flashrom_init (submapper ==1? 0x01: 0xC2, 0xA4, 65536, 0x5555, 0x2AAA, 0x7FFF); /* Macronix MX29F040 (0)/AMD AM29F040 (1) */
+	info->Power =Power;
+	info->SaveGame[0] =PRGptr[0];
+	info->SaveGameLen[0] =PRGsize[0];
+	MapIRQHook =flashrom_cpuCycle;
+}