From 8beb0a9ae5157e2604686ffea003aaf7fd00f9d2 Mon Sep 17 00:00:00 2001
From: alyosha-tas <alexei.f.k@gmail.com>
Date: Mon, 7 Oct 2019 20:04:57 -0400
Subject: [PATCH] GBHawk: MBC3: fix RTC

---
 .../Nintendo/GBHawk/Mappers/Mapper_MBC3.cs    | 24 ++++++++++---------
 1 file changed, 13 insertions(+), 11 deletions(-)

diff --git a/BizHawk.Emulation.Cores/Consoles/Nintendo/GBHawk/Mappers/Mapper_MBC3.cs b/BizHawk.Emulation.Cores/Consoles/Nintendo/GBHawk/Mappers/Mapper_MBC3.cs
index 378d156429..2cf79faa8c 100644
--- a/BizHawk.Emulation.Cores/Consoles/Nintendo/GBHawk/Mappers/Mapper_MBC3.cs
+++ b/BizHawk.Emulation.Cores/Consoles/Nintendo/GBHawk/Mappers/Mapper_MBC3.cs
@@ -61,7 +61,7 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBHawk
 			{
 				if (RAM_enable)
 				{
-					if ((Core.cart_RAM != null) && (RAM_bank < 3))
+					if ((Core.cart_RAM != null) && (RAM_bank <= RAM_mask))
 					{
 						if (((addr - 0xA000) + RAM_bank * 0x2000) < Core.cart_RAM.Length)
 						{
@@ -73,18 +73,18 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBHawk
 						}
 					}
 
-					if ((RAM_bank >= 8) && (RAM_bank < 0xC))
+					if ((RAM_bank >= 8) && (RAM_bank <= 0xC))
 					{
 						return RTC_regs_latch[RAM_bank - 8];
 					}
 					else
 					{
-						return 0xFF;
+						return 0x0;
 					}
 				}
 				else
 				{
-					return 0xFF;
+					return 0x0;
 				}
 			}
 		}
@@ -103,7 +103,7 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBHawk
 			{
 				if (RAM_enable)
 				{
-					if ((Core.cart_RAM != null) && (RAM_bank < 3))
+					if ((Core.cart_RAM != null) && (RAM_bank <= RAM_mask))
 					{
 						if (((addr - 0xA000) + RAM_bank * 0x2000) < Core.cart_RAM.Length)
 						{
@@ -115,7 +115,7 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBHawk
 						}
 					}
 
-					if ((RAM_bank >= 8) && (RAM_bank < 0xC))
+					if ((RAM_bank >= 8) && (RAM_bank <= 0xC))
 					{
 						return;
 					}
@@ -141,7 +141,7 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBHawk
 			if (addr < 0x8000)
 			{
 				if (addr < 0x2000)
-				{
+				{					
 					RAM_enable = ((value & 0xA) == 0xA);
 				}
 				else if (addr < 0x4000)
@@ -156,7 +156,7 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBHawk
 				}
 				else if (addr < 0x6000)
 				{
-					RAM_bank = value & 3;
+					RAM_bank = value;
 				}
 				else
 				{
@@ -175,17 +175,19 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBHawk
 			{
 				if (RAM_enable)
 				{
-					if ((Core.cart_RAM != null) && (RAM_bank <= 3))
+					if ((Core.cart_RAM != null) && (RAM_bank <= RAM_mask))
 					{
 						if (((addr - 0xA000) + RAM_bank * 0x2000) < Core.cart_RAM.Length)
 						{
 							Core.cart_RAM[(addr - 0xA000) + RAM_bank * 0x2000] = value;
 						}
 					}
-					else if ((RAM_bank >= 8) && (RAM_bank < 0xC))
+					else if ((RAM_bank >= 8) && (RAM_bank <= 0xC))
 					{
 						RTC_regs[RAM_bank - 8] = value;
 
+						RTC_low_clock = RTC_timer = 0;
+
 						halt = (RTC_regs[4] & 0x40) > 0;
 					}
 				}
@@ -219,6 +221,7 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBHawk
 						RTC_low_clock = 0;
 
 						RTC_regs[0]++;
+
 						if (RTC_regs[0] > 59)
 						{
 							RTC_regs[0] = 0;
@@ -255,7 +258,6 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBHawk
 			}
 		}
 
-
 		public override void SyncState(Serializer ser)
 		{
 			ser.Sync(nameof(ROM_bank), ref ROM_bank);