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commodore64: properly emulate CPU lag when VIC is accessing sprite data

This commit is contained in:
saxxonpike 2012-11-10 08:48:36 +00:00
parent ae721eef5d
commit a096b3f224
2 changed files with 17 additions and 14 deletions
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2
BizHawk.Emulation/Computers/Commodore64/C64.cs
View File

@ -92,13 +92,13 @@ namespace BizHawk.Emulation.Computers.Commodore64
for (int i = 0; i < cyclesPerFrame; i++)
{
vic.PerformCycle();
cpu.IRQ = signal.CpuIRQ;
cpu.NMI = signal.CpuNMI;
if (signal.CpuAEC)
{
cpu.ExecuteOne();
}
vic.PerformCycle();
sid.PerformCycle();
cia0.PerformCycle();
cia1.PerformCycle();

29
BizHawk.Emulation/Computers/Commodore64/VicII.cs
View File

@ -672,17 +672,17 @@ namespace BizHawk.Emulation.Computers.Commodore64
public void PerformCycle()
{
ProcessDisplayRegisters();
RenderCycle();
// increment cycle
cycle++;
if (cycle == totalCycles)
if (cycle >= totalCycles)
{
cycle = 0;
AdvanceRaster();
}
ProcessDisplayRegisters();
RenderCycle();
// increment cycle
cycle++;
UpdateInterrupts();
signal.VicIRQ = regs.IRQ;
}
@ -794,11 +794,14 @@ namespace BizHawk.Emulation.Computers.Commodore64
{
if (regs.MYE[i])
{
regs.MCBASE[i] += 3;
if (regs.MCBASE[i] == 63)
if (regs.MD[i])
{
regs.MD[i] = false;
regs.MDMA[i] = false;
regs.MCBASE[i] += 3;
if (regs.MCBASE[i] == 63)
{
regs.MD[i] = false;
regs.MDMA[i] = false;
}
}
}
}
@ -820,7 +823,7 @@ namespace BizHawk.Emulation.Computers.Commodore64
regs.MPTR[spriteIndex] = mem.VicRead(pointerOffset);
// also fetch upper 8 bits if enabled
//signal.VicAEC = regs.MDMA[spriteIndex];
signal.VicAEC = !regs.MDMA[spriteIndex];
if (regs.MDMA[spriteIndex])
{
regs.MSRC[spriteIndex] = 24;
@ -831,7 +834,7 @@ namespace BizHawk.Emulation.Computers.Commodore64
else
{
// second half of the fetch cycle
//signal.VicAEC = regs.MDMA[spriteIndex];
signal.VicAEC = !regs.MDMA[spriteIndex];
if (regs.MDMA[spriteIndex])
{
for (int i = 0; i < 2; i++)
@ -847,7 +850,7 @@ namespace BizHawk.Emulation.Computers.Commodore64
else if (spriteFetchIndex == 16)
{
// set AEC after sprite fetches
//signal.VicAEC = true;
signal.VicAEC = true;
spriteFetchIndex++;
}