From 872acac367ae5eb48613a75b3649e644ca14f18f Mon Sep 17 00:00:00 2001
From: negativeExponent <negativeExponent@users.noreply.github.com>
Date: Thu, 20 Feb 2020 12:07:38 +0800
Subject: [PATCH] Merge mapper 225 and 255, re-implement extra RAM

- merges mappers 225 and 255 since they are basically the same
- re-implement extra RAM as its required for some multicarts
---
 src/boards/225.c | 20 ++++++++++--
 src/boards/255.c | 79 ------------------------------------------------
 2 files changed, 17 insertions(+), 82 deletions(-)
 delete mode 100644 src/boards/255.c

diff --git a/src/boards/225.c b/src/boards/225.c
index 2fb9768..12576d5 100644
--- a/src/boards/225.c
+++ b/src/boards/225.c
@@ -2,6 +2,8 @@
  *
  * Copyright notice for this file:
  *  Copyright (C) 2011 CaH4e3
+  * Copyright (C) 2019 Libretro Team
+ *  Copyright (C) 2020 negativeExponent
  *
  * 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
@@ -19,15 +21,20 @@
  *
  * PCB-018 board, discrete multigame cart 110-in-1
  *
+ * Mapper 225
+ * Mapper 255
+ *
  */
 
+/* 2020-2-20 - merge mapper 255, re-implement extra RAM */
+
 #include "mapinc.h"
 
-static uint8 prot[4], prg, mode, chr, mirr;
+static uint8 extraRAM[4], prg, mode, chr, mirr;
 
 static SFORMAT StateRegs[] =
 {
-	{ prot, 4, "PROT" },
+	{ extraRAM, 4, "PROT" },
 	{ &prg, 1, "PRG" },
 	{ &chr, 1, "CHR" },
 	{ &mode, 1, "MODE" },
@@ -55,10 +62,13 @@ static DECLFW(M225Write) {
 }
 
 static DECLFW(M225LoWrite) {
+	/* e.g. 115-in-1 [p1][!] CRC32 0xb39d30b4 */
+	if (A & 0x800) extraRAM[A & 3] = V & 0x0F;
 }
 
 static DECLFR(M225LoRead) {
-	return 0;
+	if (A & 0x800) return extraRAM[A & 3];
+	return X.DB;
 }
 
 static void M225Power(void) {
@@ -87,3 +97,7 @@ void Mapper225_Init(CartInfo *info) {
 	GameStateRestore = StateRestore;
 	AddExState(&StateRegs, ~0, 0, 0);
 }
+
+void Mapper255_Init(CartInfo *info) {
+	Mapper225_Init(info);
+}
\ No newline at end of file
diff --git a/src/boards/255.c b/src/boards/255.c
deleted file mode 100644
index fc7f28c..0000000
--- a/src/boards/255.c
+++ /dev/null
@@ -1,79 +0,0 @@
-/* FCEUmm - NES/Famicom Emulator
- *
- * Copyright (C) 2019 Libretro Team
- *
- * 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
- */
-
-/* added 2019-5-23
- * Mapper 255
- * https://wiki.nesdev.com/w/index.php/INES_Mapper_225
- * 115-in-1 [p1][!] CRC32 0xb39d30b4
- * Seems to handle up to last game in the multicarts than m225 but causes
- * graphics garbage past it, else games works fine */
-
-#include "mapinc.h"
-
-static uint8 preg, creg, mode, mirr;
-
-static SFORMAT StateRegs[] =
-{
-	{ &preg, 1, "PRG0" },
-	{ &creg, 1, "CHR0" },
-	{ &mode, 1, "MODE" },
-	{ &mirr, 1, "MIRR" },
-	{ 0 }
-};
-
-static void Sync(void) {
-	setprg16(0x8000, preg & ~mode);
-	setprg16(0xC000, preg | mode);
-	setchr8(creg);
-	setmirror(mirr ^ 1);
-}
-
-static DECLFW(M255Write) {
-	uint32 bank = (A >> 8 & 0x40);
-	preg = bank | ((A >> 6) & 0x3F);
-	creg = bank | (A & 0x3F);
-	mirr = (A >> 13) & 1;
-	mode = ((~A) >> 12 & 1);
-	Sync();
-}
-
-static void M255Power(void) {
-	preg = 0;
-	mode = 1;
-	Sync();
-	SetReadHandler(0x8000, 0xFFFF, CartBR);
-	SetWriteHandler(0x8000, 0xFFFF, M255Write);
-}
-
-static void M255Reset(void) {
-	preg = 0;
-	mode = 1;
-	Sync();
-}
-
-static void StateRestore(int version) {
-	Sync();
-}
-
-void Mapper255_Init(CartInfo *info) {
-	info->Reset = M255Reset;
-	info->Power = M255Power;
-	GameStateRestore = StateRestore;
-	AddExState(&StateRegs, ~0, 0, 0);
-}