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NesHawk - better clean up of ppu open bus decay method even more, this should be more performant too

This commit is contained in:
adelikat 2017-06-28 13:44:55 -05:00
parent bc8ac1c1a4
commit 3c799931bc
2 changed files with 53 additions and 51 deletions
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2
BizHawk.Emulation.Cores/Consoles/Nintendo/NES/PPU.cs
View File

@ -310,7 +310,7 @@ namespace BizHawk.Emulation.Cores.Nintendo.NES
nes.RunCpuOne(); nes.RunCpuOne();
// decay the ppu bus, approximating real behaviour // decay the ppu bus, approximating real behaviour
ppu_open_bus_decay(0); PpuOpenBusDecay(DecayType.None);
// Check for NMIs // Check for NMIs
if (NMI_PendingInstructions > 0) if (NMI_PendingInstructions > 0)

100
BizHawk.Emulation.Cores/Consoles/Nintendo/NES/PPU.regs.cs
View File

@ -365,7 +365,7 @@ namespace BizHawk.Emulation.Cores.Nintendo.NES
// update the open bus here // update the open bus here
ppu_open_bus = ret; ppu_open_bus = ret;
ppu_open_bus_decay(2); PpuOpenBusDecay(DecayType.High);
return ret; return ret;
} }
byte peek_2002() byte peek_2002()
@ -468,7 +468,7 @@ namespace BizHawk.Emulation.Cores.Nintendo.NES
} }
ppu_open_bus = ret; ppu_open_bus = ret;
ppu_open_bus_decay(1); PpuOpenBusDecay(DecayType.All);
return ret; return ret;
} }
byte peek_2004() { return OAM[reg_2003]; } byte peek_2004() { return OAM[reg_2003]; }
@ -595,10 +595,11 @@ namespace BizHawk.Emulation.Cores.Nintendo.NES
ppu_open_bus = ret; ppu_open_bus = ret;
if (bus_case==0) if (bus_case==0)
{ {
ppu_open_bus_decay(1); PpuOpenBusDecay(DecayType.All);
} else }
else
{ {
ppu_open_bus_decay(3); PpuOpenBusDecay(DecayType.Low);
} }
return ret; return ret;
@ -671,6 +672,7 @@ namespace BizHawk.Emulation.Cores.Nintendo.NES
default: throw new InvalidOperationException(); default: throw new InvalidOperationException();
} }
} }
public byte PeekReg(int addr) public byte PeekReg(int addr)
{ {
switch (addr) switch (addr)
@ -680,6 +682,7 @@ namespace BizHawk.Emulation.Cores.Nintendo.NES
default: throw new InvalidOperationException(); default: throw new InvalidOperationException();
} }
} }
public void WriteReg(int addr, byte value) public void WriteReg(int addr, byte value)
{ {
PPUGenLatch = value; PPUGenLatch = value;
@ -709,55 +712,54 @@ namespace BizHawk.Emulation.Cores.Nintendo.NES
} }
} }
public void ppu_open_bus_decay(byte action) private enum DecayType
{ {
// if there is no action, decrement the timer None = 0, // if there is no action, decrement the timer
if (action == 0) All = 1, // reset the timer for all bits (reg 2004 / 2007 (non-palette)
{ High = 2, // reset the timer for high 3 bits (reg 2002)
for (int i = 0; i < 8; i++) Low = 3 // reset the timer for all low 6 bits (reg 2007 (palette))
{
if (ppu_open_bus_decay_timer[i] == 0)
{
ppu_open_bus = (byte)(ppu_open_bus & (0xff - (1 << i)));
ppu_open_bus_decay_timer[i] = 1786840; // about 1 second worth of cycles
}
else
{
ppu_open_bus_decay_timer[i]--;
}
}
}
// reset the timer for all bits (reg 2004 / 2007 (non-palette)
else if (action == 1)
{
for (int i = 0; i < 8; i++)
{
ppu_open_bus_decay_timer[i] = 1786840;
}
}
// reset the timer for high 3 bits (reg 2002)
else if (action == 2)
{
ppu_open_bus_decay_timer[7] = 1786840;
ppu_open_bus_decay_timer[6] = 1786840;
ppu_open_bus_decay_timer[5] = 1786840;
}
// reset the timer for all low 6 bits (reg 2007 (palette))
else if (action == 3)
{
for (int i = 0; i < 6; i++)
{
ppu_open_bus_decay_timer[i] = 1786840;
}
}
// other values of action are reserved for possibly needed expansions, but this passes // other values of action are reserved for possibly needed expansions, but this passes
// ppu_open_bus for now. // ppu_open_bus for now.
} }
private void PpuOpenBusDecay(DecayType action)
{
switch (action)
{
case DecayType.None:
for (int i = 0; i < 8; i++)
{
if (ppu_open_bus_decay_timer[i] == 0)
{
ppu_open_bus = (byte)(ppu_open_bus & (0xff - (1 << i)));
ppu_open_bus_decay_timer[i] = 1786840; // about 1 second worth of cycles
}
else
{
ppu_open_bus_decay_timer[i]--;
}
}
break;
case DecayType.All:
for (int i = 0; i < 8; i++)
{
ppu_open_bus_decay_timer[i] = 1786840;
}
break;
case DecayType.High:
ppu_open_bus_decay_timer[7] = 1786840;
ppu_open_bus_decay_timer[6] = 1786840;
ppu_open_bus_decay_timer[5] = 1786840;
break;
case DecayType.Low:
for (int i = 0; i < 6; i++)
{
ppu_open_bus_decay_timer[i] = 1786840;
}
break;
}
}
} }
} }