From e46914d42e12ab7e5bd5ef251d0a22b53797cbdf Mon Sep 17 00:00:00 2001
From: NewRisingSun <8vytz1+dhp372pv94ebg@sharklasers.com>
Date: Tue, 9 Sep 2025 21:24:00 +0200
Subject: [PATCH] Add mapper 537. Note that the UNIF dump of this mapper's
 JY-103 game has a strange bank order and will not run.

---
 src/boards/537.c | 60 ++++++++++++++++++++++++++++++++++++++++++++++++
 src/ines.c       |  1 +
 src/ines.h       |  1 +
 3 files changed, 62 insertions(+)
 create mode 100644 src/boards/537.c

diff --git a/src/boards/537.c b/src/boards/537.c
new file mode 100644
index 0000000..e628180
--- /dev/null
+++ b/src/boards/537.c
@@ -0,0 +1,60 @@
+/* FCEUmm - NES/Famicom Emulator
+ *
+ * Copyright notice for this file:
+ *  Copyright (C) 2020
+ *
+ * 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
+ *
+ *
+ */
+
+/* The UNIF dump of "(JY-103) 3-in-1" (JY4M4 MAPR) has a strange bank order and will not run with this emulation. */
+
+#include "mapinc.h"
+#include "asic_mmc3.h"
+
+static uint8 reg[2];
+
+static void sync () {
+	int prgAND = reg[0] &0x80? 0x0F: 0x1F;
+	int chrAND = 0xFF;
+	int prgOR = reg[0] >>1 &0x20 | reg[1] <<4 &0x10;
+	int chrOR = reg[0] <<2 &0x100;
+	MMC3_syncPRG(prgAND, prgOR &~prgAND);
+	MMC3_syncCHR(chrAND, chrOR &~chrAND);
+	MMC3_syncMirror();
+}
+
+static DECLFW (writeReg) {
+	reg[A &1] = V;
+	sync();
+}
+
+static void reset () {
+	reg[0] = reg[1] = 0;
+	MMC3_clear();
+}
+
+static void power () {
+	reg[0] = reg[1] = 0;
+	MMC3_power();
+}
+
+void Mapper537_Init (CartInfo *info) {
+	MMC3_init(info, sync, MMC3_TYPE_AX5202P, NULL, NULL, NULL, writeReg);
+	info->Power = power;
+	info->Reset = reset;
+	AddExState(reg, 2, 0, "EXPR");
+}
diff --git a/src/ines.c b/src/ines.c
index b64cb24..490e7a5 100644
--- a/src/ines.c
+++ b/src/ines.c
@@ -933,6 +933,7 @@ INES_BOARD_BEGIN()
 	INES_BOARD( "Sachen 3014",              533, Mapper533_Init         )
 	INES_BOARD( "NJ064",                    534, Mapper534_Init         )
 	INES_BOARD( "LH53",                     535, LH53_Init              )
+	INES_BOARD( "JY4M4",                    537, Mapper537_Init         )
 	INES_BOARD( "60-1064-16L (FDS)",        538, Mapper538_Init         )
 	INES_BOARD( "Kid Ikarus (FDS)",         539, Mapper539_Init         )
 	INES_BOARD( "82112C",                   540, Mapper540_Init         )
diff --git a/src/ines.h b/src/ines.h
index ed48f1d..8a0ca24 100644
--- a/src/ines.h
+++ b/src/ines.h
@@ -401,6 +401,7 @@ void Mapper523_Init(CartInfo *);
 void Mapper528_Init(CartInfo *);
 void Mapper533_Init(CartInfo *);
 void Mapper534_Init(CartInfo *);
+void Mapper537_Init(CartInfo *);
 void Mapper538_Init(CartInfo *);
 void Mapper539_Init(CartInfo *);
 void Mapper540_Init(CartInfo *);