From cea8fc87eba91a40dad48922c6644c4627bccc1c Mon Sep 17 00:00:00 2001
From: NewRisingSun <8vytz1+dhp372pv94ebg@sharklasers.com>
Date: Tue, 9 Sep 2025 23:52:54 +0200
Subject: [PATCH] Add mapper 400.

---
 src/boards/400.c | 58 ++++++++++++++++++++++++++++++++++++++++++++++++
 src/ines.c       |  1 +
 src/ines.h       |  1 +
 3 files changed, 60 insertions(+)
 create mode 100644 src/boards/400.c

diff --git a/src/boards/400.c b/src/boards/400.c
new file mode 100644
index 0000000..3965439
--- /dev/null
+++ b/src/boards/400.c
@@ -0,0 +1,58 @@
+/* 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 uint8 reg[4];
+
+static void sync () {
+	setprg16(0x8000, reg[2] &~0x07 | Latch_data &0x07);
+	setprg16(0xC000, reg[3] &~0x07 |             0x07);
+	setchr8(Latch_data >>5);
+	setmirror(reg[3] &0x20? MI_H: MI_V);
+}
+
+static DECLFW (writeReg) {
+	if (!(A &0x7FF)) { /* Exclude 8 Bit Xmas 2008's writes to second APU (also at 7001-7015) */
+		reg[A >>11 &3] = V;
+		sync();
+	}
+}
+
+static void power () {
+	reg[0] = reg[1] = reg[2] = 0;
+	reg[3] = 0x80;
+	Latch_power();
+	SetWriteHandler(0x6000, 0x7FFF, writeReg);
+}
+
+static void reset () {
+	reg[0] = reg[1] = reg[2] = 0;
+	reg[3] = 0x80;
+	Latch_clear();
+}
+
+void Mapper400_Init (CartInfo *info) {
+	Latch_init(info, sync, 0xC000, 0xFFFF, NULL);
+	info->Power = power;
+	info->Reset = reset;
+	AddExState(reg, 4, 0, "REGS");
+}
diff --git a/src/ines.c b/src/ines.c
index 67fcaa1..c79e6a4 100644
--- a/src/ines.c
+++ b/src/ines.c
@@ -836,6 +836,7 @@ INES_BOARD_BEGIN()
 	INES_BOARD( "YY850439C",                397, Mapper397_Init         )
 	INES_BOARD( "YY840820C",                398, Mapper398_Init         )
 	INES_BOARD( "BATMAP-000",               399, Mapper399_Init         )
+	INES_BOARD( "8BIT-XMAS",                400, Mapper400_Init         )
 	INES_BOARD( "BMC Super 19-in-1 (VIP19)",401, Mapper401_Init         )
 	INES_BOARD( "831019C J-2282",           402, J2282_Init             )
 	INES_BOARD( "89433",                    403, Mapper403_Init         )
diff --git a/src/ines.h b/src/ines.h
index 9618844..d305db7 100644
--- a/src/ines.h
+++ b/src/ines.h
@@ -317,6 +317,7 @@ void Mapper396_Init(CartInfo *);
 void Mapper397_Init(CartInfo *);
 void Mapper398_Init(CartInfo *);
 void Mapper399_Init(CartInfo *);
+void Mapper400_Init(CartInfo *);
 void Mapper401_Init(CartInfo *);
 void Mapper403_Init(CartInfo *);
 void Mapper404_Init(CartInfo *);