From ffbb1f3399d647dec0e979baad6447b148c65616 Mon Sep 17 00:00:00 2001
From: alyosha-tas <alexei.f.k@gmail.com>
Date: Fri, 24 Nov 2017 12:24:22 -0500
Subject: [PATCH] GBHawk: Bug Fixes

---
 .../Consoles/Nintendo/GBHawk/MemoryMap.cs     | 60 +++++++++++--------
 .../Consoles/Nintendo/GBHawk/PPU.cs           | 12 +++-
 2 files changed, 45 insertions(+), 27 deletions(-)

diff --git a/BizHawk.Emulation.Cores/Consoles/Nintendo/GBHawk/MemoryMap.cs b/BizHawk.Emulation.Cores/Consoles/Nintendo/GBHawk/MemoryMap.cs
index 3564245b4c..b1b241d39b 100644
--- a/BizHawk.Emulation.Cores/Consoles/Nintendo/GBHawk/MemoryMap.cs
+++ b/BizHawk.Emulation.Cores/Consoles/Nintendo/GBHawk/MemoryMap.cs
@@ -33,22 +33,27 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBHawk
 			
 			if (ppu.DMA_start)
 			{
-				if ((addr >= 0xFE00) && (addr < 0xFEA0) && ppu.DMA_OAM_access)
+				if (addr < 0x4000)
 				{
-					return OAM[addr - 0xFE00];
-				}
-				else if ((addr >= 0xFF80))
-				{
-					return ZP_RAM[addr - 0xFF80];
+					return mapper.ReadMemory(addr); // some of gekkio's tests require this to be accessible during DMA
 				}
 				else if ((addr >= 0xE000) && (addr < 0xFE00))
 				{
 					return RAM[addr - 0xE000]; // some of gekkio's tests require this to be accessible during DMA
 				}
-				else if (addr < 0x4000)
+				else if ((addr >= 0xFE00) && (addr < 0xFEA0) && ppu.DMA_OAM_access)
 				{
-					return mapper.ReadMemory(addr); // some of gekkio's tests require this to be accessible during DMA
+					return OAM[addr - 0xFE00];
 				}
+				else if ((addr >= 0xFF00) && (addr < 0xFF80)) // The game GOAL! Requires Hardware Regs to be accessible
+				{
+					return Read_Registers(addr);
+				}
+				else if ((addr >= 0xFF80))
+				{
+					return ZP_RAM[addr - 0xFF80];
+				}
+				
 				return 0xFF;
 			}
 			
@@ -126,22 +131,22 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBHawk
 			
 			if (ppu.DMA_start)
 			{
-				if ((addr >= 0xFE00) && (addr < 0xFEA0) && ppu.DMA_OAM_access)
+				if ((addr >= 0xE000) && (addr < 0xFE00))
+				{
+					RAM[addr - 0xE000] = value; // some of gekkio's tests require this to be accessible during DMA
+				}
+				else if ((addr >= 0xFE00) && (addr < 0xFEA0) && ppu.DMA_OAM_access)
 				{
 					OAM[addr - 0xFE00] = value; 
 				}
+				else if ((addr >= 0xFF00) && (addr < 0xFF80)) // The game GOAL! Requires Hardware Regs to be accessible
+				{
+					Write_Registers(addr, value);
+				}
 				else if ((addr >= 0xFF80))
 				{
 					ZP_RAM[addr - 0xFF80] = value;
 				}
-				else if (addr == 0xFF46)
-				{
-					Write_Registers(addr, value); // a second DMA can start, but what about other registers?
-				}
-				else if ((addr >= 0xE000) && (addr < 0xFE00))
-				{
-					RAM[addr - 0xE000] = value; // some of gekkio's tests require this to be accessible during DMA
-				}
 				return;
 			}
 
@@ -211,22 +216,27 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBHawk
 		{
 			if (ppu.DMA_start)
 			{
-				if ((addr >= 0xFE00) && (addr < 0xFEA0) && ppu.DMA_OAM_access)
+				if (addr < 0x4000)
 				{
-					return OAM[addr - 0xFE00];
-				}
-				else if ((addr >= 0xFF80))
-				{
-					return ZP_RAM[addr - 0xFF80];
+					return mapper.ReadMemory(addr); // some of gekkio's tests require this to be accessible during DMA
 				}
 				else if ((addr >= 0xE000) && (addr < 0xFE00))
 				{
 					return RAM[addr - 0xE000]; // some of gekkio's tests require this to be accessible during DMA
 				}
-				else if (addr < 0x4000)
+				else if ((addr >= 0xFE00) && (addr < 0xFEA0) && ppu.DMA_OAM_access)
 				{
-					return mapper.PeekMemory(addr); // some of gekkio's tests require this to be accessible during DMA
+					return OAM[addr - 0xFE00];
 				}
+				else if ((addr >= 0xFF00) && (addr < 0xFF80)) // The game GOAL! Requires Hardware Regs to be accessible
+				{
+					return Read_Registers(addr);
+				}
+				else if ((addr >= 0xFF80))
+				{
+					return ZP_RAM[addr - 0xFF80];
+				}
+
 				return 0xFF;
 			}
 
diff --git a/BizHawk.Emulation.Cores/Consoles/Nintendo/GBHawk/PPU.cs b/BizHawk.Emulation.Cores/Consoles/Nintendo/GBHawk/PPU.cs
index 5b94e3b3b5..1bcb384241 100644
--- a/BizHawk.Emulation.Cores/Consoles/Nintendo/GBHawk/PPU.cs
+++ b/BizHawk.Emulation.Cores/Consoles/Nintendo/GBHawk/PPU.cs
@@ -117,6 +117,14 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBHawk
 			switch (addr)
 			{
 				case 0xFF40: // LCDC
+					if (LCDC.Bit(7) && !value.Bit(7))
+					{
+						VRAM_access_read = true;
+						VRAM_access_write = true;
+						OAM_access_read = true;
+						OAM_access_write = true;
+					}
+
 					LCDC = value;
 					break; 
 				case 0xFF41: // STAT
@@ -1047,8 +1055,8 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBHawk
 			BGP = 0xFF;
 			obj_pal_0 = 0xFF;
 			obj_pal_1 = 0xFF;
-			window_y = 0;
-			window_x = 0;
+			window_y = 0x0;
+			window_x = 0x0;
 			LY_inc = 1;
 			no_scan = false;
 			OAM_access_read = true;