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GBHawk: Fix memory accesses during DMA

This commit is contained in:
alyosha-tas 2017-11-21 13:26:40 -05:00
parent 7a987810ef
commit 63f8fc0d90
2 changed files with 49 additions and 9 deletions
BizHawk.Emulation.Cores/Consoles/Nintendo/GBHawk
MemoryMap.csPPU.cs

44
BizHawk.Emulation.Cores/Consoles/Nintendo/GBHawk/MemoryMap.cs
View File

@ -30,7 +30,28 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBHawk
public byte ReadMemory(ushort addr)
{
MemoryCallbacks.CallReads(addr, "System Bus");
if (ppu.DMA_start)
{
if ((addr >= 0xFE00) && (addr < 0xFEA0) && ppu.DMA_OAM_access)
{
return OAM[addr - 0xFE00];
}
else if ((addr >= 0xFF80))
{
return ZP_RAM[addr - 0xFF80];
}
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)
{
return mapper.ReadMemory(addr); // some of gekkio's tests require this to be accessible during DMA
}
return 0xFF;
}
if (addr < 0x100)
{
// return Either BIOS ROM or Game ROM
@ -102,6 +123,27 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBHawk
public void WriteMemory(ushort addr, byte value)
{
MemoryCallbacks.CallWrites(addr, "System Bus");
if (ppu.DMA_start)
{
if ((addr >= 0xFE00) && (addr < 0xFEA0) && ppu.DMA_OAM_access)
{
OAM[addr - 0xFE00] = 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;
}
if (addr < 0x100)
{

14
BizHawk.Emulation.Cores/Consoles/Nintendo/GBHawk/PPU.cs
View File

@ -9,8 +9,6 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBHawk
{
public GBHawk Core { get; set; }
//public byte BGP_l;
// register variables
public byte LCDC;
public byte STAT;
@ -41,6 +39,7 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBHawk
public bool stat_line_old;
public int hbl_countdown;
// OAM scan
public bool DMA_OAM_access;
public bool OAM_access_read;
public bool OAM_access_write;
public int OAM_scan_index;
@ -141,6 +140,7 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBHawk
case 0xFF46: // DMA
DMA_addr = value;
DMA_start = true;
DMA_OAM_access = true;
DMA_clock = 0;
DMA_inc = 0;
break;
@ -169,14 +169,13 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBHawk
{
if (DMA_clock >= 4)
{
OAM_access_read = false;
OAM_access_write = false;
DMA_OAM_access = false;
if ((DMA_clock % 4) == 1)
{
// the cpu can't access memory during this time, but we still need the ppu to be able to.
OAM_access_read = true;
DMA_start = false;
DMA_byte = Core.ReadMemory((ushort)((DMA_addr << 8) + DMA_inc));
OAM_access_read = false;
DMA_start = true;
}
else if ((DMA_clock % 4) == 3)
{
@ -197,8 +196,6 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBHawk
if (DMA_clock == 648)
{
OAM_access_read = true;
OAM_access_write = true;
DMA_start = false;
}
}
@ -1161,6 +1158,7 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBHawk
ser.Sync("write_sprite", ref write_sprite);
ser.Sync("no_scan", ref no_scan);
ser.Sync("DMA_OAM_access", ref DMA_OAM_access);
ser.Sync("OAM_access_read", ref OAM_access_read);
ser.Sync("OAM_access_write", ref OAM_access_write);
ser.Sync("VRAM_access_read", ref VRAM_access_read);