From 2c0c3c1876be55141032d218b464d4192251e3c5 Mon Sep 17 00:00:00 2001
From: NewRisingSun <8vytz1+dhp372pv94ebg@sharklasers.com>
Date: Mon, 8 Sep 2025 23:14:17 +0200
Subject: [PATCH] Add mapper 504.

---
 src/boards/432.c |  2 +-
 src/boards/504.c | 65 ++++++++++++++++++++++++++++++++++++++++++++++++
 src/ines.c       |  1 +
 src/ines.h       |  1 +
 4 files changed, 68 insertions(+), 1 deletion(-)
 create mode 100644 src/boards/504.c

diff --git a/src/boards/432.c b/src/boards/432.c
index dadf0d4..002718d 100644
--- a/src/boards/432.c
+++ b/src/boards/432.c
@@ -45,7 +45,7 @@ static void sync() {
 static int getPRGBank(uint8 bank) {
 	if (reg[1] &0x40) {
 		int mask = reg[1] &(submapper == 2? 0x20: 0x80)? 3: 1;
-		return MMC3_getPRGBank(bank & 1) &~mask | bank &mask;
+		return MMC3_getPRGBank(bank &1) &~mask | bank &mask;
 	} else
 		return MMC3_getPRGBank(bank);
 }
diff --git a/src/boards/504.c b/src/boards/504.c
new file mode 100644
index 0000000..1d4b777
--- /dev/null
+++ b/src/boards/504.c
@@ -0,0 +1,65 @@
+/* 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
+ *
+ *
+ */
+
+#include "mapinc.h"
+#include "asic_mmc3.h"
+
+static uint8 reg;
+
+static void sync() {
+	int prgAND = reg &0x02? 0x0F: 0x1F;
+	int chrAND = reg &0x02? 0x7F: 0xFF;
+	int prgOR = reg <<4;
+	int chrOR = reg <<7;
+	MMC3_syncPRG(prgAND, prgOR &~prgAND);
+	MMC3_syncCHR(chrAND, chrOR &~chrAND);
+	MMC3_syncMirror();
+}
+
+static int getPRGBank(uint8 bank) {
+	if ((reg &0x03) == 0x03 && ~reg &0x08)
+		return MMC3_getPRGBank(bank &1) &~1 | bank &1;
+	else
+		return MMC3_getPRGBank(bank);
+}
+
+static DECLFW(writeReg) {
+	reg = A &0xFF;
+	sync();
+}
+
+static void reset() {
+	reg = 0;
+	sync();
+}
+
+static void power() {
+	reg = 0;
+	MMC3_power();
+}
+
+void Mapper504_Init(CartInfo *info) {
+	MMC3_init(info, sync, MMC3_TYPE_AX5202P, getPRGBank, NULL, NULL, writeReg);
+	info->Power = power;
+	info->Reset = reset;
+	AddExState(&reg, 1, 0, "EXPR");
+}
diff --git a/src/ines.c b/src/ines.c
index 93faa2c..77957e7 100644
--- a/src/ines.c
+++ b/src/ines.c
@@ -913,6 +913,7 @@ INES_BOARD_BEGIN()
 	INES_BOARD( "Yhc-001",                  501, Mapper501_Init         )
 	INES_BOARD( "Yhc-002",                  502, Mapper502_Init         )
 	INES_BOARD( "ET-170",                   503, Mapper503_Init         )
+	INES_BOARD( "K-3054",                   504, Mapper504_Init         )
 	INES_BOARD( "SA-9602B",                 513, SA9602B_Init           )
 	INES_BOARD( "Brilliant Com Cocoma Pack",516, Mapper516_Init        )
 	INES_BOARD( "DANCE2000",                518, UNLD2000_Init          )
diff --git a/src/ines.h b/src/ines.h
index c16b741..a8e4590 100644
--- a/src/ines.h
+++ b/src/ines.h
@@ -392,6 +392,7 @@ void Mapper500_Init(CartInfo *);
 void Mapper501_Init(CartInfo *);
 void Mapper502_Init(CartInfo *);
 void Mapper503_Init(CartInfo *);
+void Mapper504_Init(CartInfo *);
 void Mapper516_Init(CartInfo *);
 void Mapper520_Init(CartInfo *);
 void Mapper523_Init(CartInfo *);