Add mapper 590.

src/boards/590.c

@@ -0,0 +1,37 @@
+/* FCE Ultra - 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 "asic_latch.h"
+
+static void sync () {
+	if (Latch_data &0x08)
+		setprg32(0x8000, Latch_data >>1);
+	else {
+		setprg16(0x8000, Latch_data);
+		setprg16(0xC000, Latch_data);
+	}
+	setchr8(Latch_data);
+}
+
+void Mapper590_Init (CartInfo *info) {
+	Latch_init(info, sync, 0x8000, 0xFFFF, NULL);
+	info->Reset = Latch_power;
+}