From 7c7b87670e2a3fef90ebd01e6db72bc6ed63cf78 Mon Sep 17 00:00:00 2001
From: norill <norill@wp.pl>
Date: Wed, 8 Apr 2020 04:28:19 +0200
Subject: [PATCH] Mapper 15: Improved accuracy (#800)

fixed 2 inaccuracies:
- not making CHR read only in modes 0 and 3
- always using last bank in mode 1 instead of using bank B | 7
---
 Core/Mapper15.h | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/Core/Mapper15.h b/Core/Mapper15.h
index ec0ba695..d503d16e 100644
--- a/Core/Mapper15.h
+++ b/Core/Mapper15.h
@@ -24,7 +24,11 @@ protected:
 		
 		uint8_t subBank = value >> 7;
 		uint8_t bank = (value & 0x7F) << 1;
-		switch(addr & 0x03) {
+		uint8_t mode = addr & 0x03;
+		
+		SetPpuMemoryMapping(0, 0x1FFF, 0, ChrMemoryType::Default, (mode == 0 || mode == 3) ? MemoryAccessType::Read : MemoryAccessType::ReadWrite);
+		
+		switch(mode) {
 			case 0:
 				SelectPRGPage(0, bank  ^ subBank);
 				SelectPRGPage(1, (bank + 1) ^ subBank);
@@ -37,7 +41,7 @@ protected:
 				bank |= subBank;
 				SelectPRGPage(0, bank);
 				SelectPRGPage(1, bank + 1);
-				bank = ((addr & 0x02) ? bank : 0xFE) | subBank;
+				bank = ((mode == 3) ? bank : (bank | 0x14)) | subBank;
 				SelectPRGPage(2, bank + 0);
 				SelectPRGPage(3, bank + 1);
 				break;