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NES: Some PPU cleanup

This commit is contained in:
alyosha-tas 2017-01-25 19:17:24 -05:00 committed by GitHub
parent d8d0c62adf
commit 647f0914ed
2 changed files with 70 additions and 56 deletions
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79
BizHawk.Emulation.Cores/Consoles/Nintendo/NES/PPU.regs.cs
View File

@ -58,8 +58,6 @@ namespace BizHawk.Emulation.Cores.Nintendo.NES
// this byte is used to simulate open bus reads and writes
// it should be modified by every read and write to a ppu register
public byte ppu_open_bus=0;
public bool s_latch_clear;
public bool d_latch_clear;
public int double_2007_read; // emulates a hardware bug of back to back 2007 reads
public int[] ppu_open_bus_decay_timer = new int[8];
@ -171,14 +169,6 @@ namespace BizHawk.Emulation.Cores.Nintendo.NES
h = _h;
}
public void clear_latches()
{
_fv = _v = _h = _vt = _ht = 0;
fh = 0;
ppu.d_latch_clear = true;
ppu.s_latch_clear = true;
}
public void increment_hsc()
{
//The first one, the horizontal scroll counter, consists of 6 bits, and is
@ -344,9 +334,14 @@ namespace BizHawk.Emulation.Cores.Nintendo.NES
if (!reg_2000.vblank_nmi_gen & ((value & 0x80) != 0) && (Reg2002_vblank_active) && !Reg2002_vblank_clear_pending)
{
//if we just unleashed the vblank interrupt then activate it now
NMI_PendingInstructions = 2;
//if (ppudead != 1)
NMI_PendingInstructions = 2;
//NMI_PendingInstructions = 2;
}
reg_2000.Value = value;
//reg_2000.Value = value;
//if (ppudead != 1)
reg_2000.Value = value;
}
@ -366,11 +361,9 @@ namespace BizHawk.Emulation.Cores.Nintendo.NES
void write_2002(byte value) { }
byte read_2002()
{
//once we thought we clear latches here, but that caused midframe glitches.
//i think we should only reset the state machine for 2005/2006
//ppur.clear_latches();
byte ret = peek_2002();
// reading from $2002 resets the destination for $2005 and $2006 writes
vtoggle = false;
Reg2002_vblank_active = 0;
Reg2002_vblank_active_pending = false;
@ -477,7 +470,7 @@ namespace BizHawk.Emulation.Cores.Nintendo.NES
{
if (!vtoggle)
{
ppur._ht= value >> 3;
ppur._ht = value >> 3;
ppur.fh = value & 7;
//nes.LogLine("scroll wrote ht = {0} and fh = {1}", ppur._ht, ppur.fh);
}
@ -495,36 +488,32 @@ namespace BizHawk.Emulation.Cores.Nintendo.NES
//VRAM address register (write)
void write_2006(byte value)
{
//if (d_latch_clear)
//{
if (!vtoggle)
{
ppur._vt &= 0x07;
ppur._vt |= (value & 0x3) << 3;
ppur._h = (value >> 2) & 1;
ppur._v = (value >> 3) & 1;
ppur._fv = (value >> 4) & 3;
//nes.LogLine("addr wrote fv = {0}", ppur._fv);
}
else
{
ppur._vt &= 0x18;
ppur._vt |= (value >> 5);
ppur._ht = value & 31;
ppur.install_latches();
//nes.LogLine("addr wrote vt = {0}, ht = {1}", ppur._vt, ppur._ht);
d_latch_clear = false;
//normally the address isnt observed by the board till it gets clocked by a read or write.
//but maybe thats just because a ppu read/write shoves it on the address bus
//apparently this shoves it on the address bus, too, or else blargg's mmc3 tests dont pass
//ONLY if the ppu is not rendering
if (ppur.status.sl == 241 || (!reg_2001.show_obj && !reg_2001.show_bg))
nes.Board.AddressPPU(ppur.get_2007access());
}
if (!vtoggle)
{
ppur._vt &= 0x07;
ppur._vt |= (value & 0x3) << 3;
ppur._h = (value >> 2) & 1;
ppur._v = (value >> 3) & 1;
ppur._fv = (value >> 4) & 3;
//nes.LogLine("addr wrote fv = {0}", ppur._fv);
}
else
{
ppur._vt &= 0x18;
ppur._vt |= (value >> 5);
ppur._ht = value & 31;
ppur.install_latches();
//nes.LogLine("addr wrote vt = {0}, ht = {1}", ppur._vt, ppur._ht);
//normally the address isnt observed by the board till it gets clocked by a read or write.
//but maybe thats just because a ppu read/write shoves it on the address bus
//apparently this shoves it on the address bus, too, or else blargg's mmc3 tests dont pass
//ONLY if the ppu is not rendering
if (ppur.status.sl == 241 || (!reg_2001.show_obj && !reg_2001.show_bg))
nes.Board.AddressPPU(ppur.get_2007access());
}
vtoggle ^= true;
vtoggle ^= true;
//}
}
byte read_2006() { return ppu_open_bus; }
byte peek_2006() { return ppu_open_bus; }

47
BizHawk.Emulation.Cores/Consoles/Nintendo/NES/PPU.run.cs
View File

@ -105,16 +105,8 @@ namespace BizHawk.Emulation.Cores.Nintendo.NES
at &= 0x03;
at <<= 2;
bgdata.at = at;
//horizontal scroll clocked at cycle 3 and then
//vertical scroll at 251
runppu(1);
if (reg_2001.PPUON)
{
ppur.increment_hsc();
if (ppur.status.cycle == 251)
ppur.increment_vs();
}
break;
}
case 3:
@ -132,9 +124,20 @@ namespace BizHawk.Emulation.Cores.Nintendo.NES
ppu_addr_temp |= 8;
bgdata.pt_1 = ppubus_read(ppu_addr_temp, true, true);
runppu(1);
//horizontal scroll clocked at cycle 3 and then
//vertical scroll at 255
if (reg_2001.PPUON)
{
ppur.increment_hsc();
if (ppur.status.cycle == 255)
ppur.increment_vs();
}
break;
case 7:
runppu(1);
break;
} //switch(cycle)
}
@ -638,10 +641,32 @@ namespace BizHawk.Emulation.Cores.Nintendo.NES
//register before around a full frame, but no games
//should write to those regs during that time, it needs
//to wait for vblank
/*
if (ppudead < 2)
{
ppur.status.sl = 241;
runppu(1);
Reg2002_vblank_active = true;
runppu(5);
runppu(postNMIlines * kLineTime - 6);
ppur.status.sl = 0;
clear_2002();
}
if (ppudead==2)
{
*/
runppu(241 * kLineTime-7*3);
//runppu(preNMIlines * kLineTime);
--ppudead;
/*
} else
{
runppu(241 * kLineTime);
runppu(preNMIlines * kLineTime);
idleSynch ^= true;
}
*/
ppudead--;
}
}
}