From 6d13706e53621acbff901b6e9d609ca13b9e3192 Mon Sep 17 00:00:00 2001
From: NewRisingSun <8vytz1+dhp372pv94ebg@sharklasers.com>
Date: Sat, 6 Aug 2022 17:29:24 +0200
Subject: [PATCH] Add mapper 52 submapper 13 (CHR-ROM+CHR-RAM)

---
 src/boards/mmc3.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/src/boards/mmc3.c b/src/boards/mmc3.c
index 633f0b5..b90e7cb 100644
--- a/src/boards/mmc3.c
+++ b/src/boards/mmc3.c
@@ -659,7 +659,10 @@ static void M52CW(uint32 A, uint8 V) {
 	uint32 mask = 0xFF ^ ((EXPREGS[0] & 0x40) << 1);
 /*	uint32 bank = (((EXPREGS[0]>>3)&4)|((EXPREGS[0]>>1)&2)|((EXPREGS[0]>>6)&(EXPREGS[0]>>4)&1))<<7; */
 	uint32 bank = (((EXPREGS[0] >> 4) & 2) | (EXPREGS[0] & 4) | ((EXPREGS[0] >> 6) & (EXPREGS[0] >> 4) & 1)) << 7;	/* actually 256K CHR banks index bits is inverted! */
-	setchr1(A, bank | (V & mask));
+	if (CHRRAM && (EXPREGS[0] &3) ==3)
+		setchr1r(0x10, A, bank | (V & mask));
+	else
+		setchr1(A, bank | (V & mask));
 }
 
 static DECLFW(M52Write) {
@@ -691,6 +694,12 @@ void Mapper52_Init(CartInfo *info) {
 	info->Reset = M52Reset;
 	info->Power = M52Power;
 	AddExState(EXPREGS, 2, 0, "EXPR");
+	if (info->iNES2 && info->submapper ==13) {
+		CHRRAMSIZE = 8192;
+		CHRRAM = (uint8*)FCEU_gmalloc(CHRRAMSIZE);
+		SetupCartCHRMapping(0x10, CHRRAM, CHRRAMSIZE, 1);
+		AddExState(CHRRAM, CHRRAMSIZE, 0, "CHRR");		
+	}
 }
 
 /* ---------------------------- Mapper 76 ------------------------------- */