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SxROM: 1% speedup

This commit is contained in:
goyuken 2012-11-02 17:51:07 +00:00
parent 03b5cd4cc4
commit 5bf33b54a6
1 changed files with 5 additions and 12 deletions
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17
BizHawk.Emulation/Consoles/Nintendo/NES/Boards/SxROM.cs
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@ -207,25 +207,19 @@ namespace BizHawk.Emulation.Consoles.Nintendo
//configuration //configuration
protected int prg_mask, chr_mask; protected int prg_mask, chr_mask;
protected int vram_mask; protected int vram_mask;
const int pputimeout = 4; // i don't know if this is right, but anything lower will not boot Bill & Ted
bool disablemirror = false; // mapper 171: mmc1 without mirroring control bool disablemirror = false; // mapper 171: mmc1 without mirroring control
//state //state
public MMC1 mmc1; public MMC1 mmc1;
/// <summary>number of cycles since last WritePRG()</summary> /// <summary>cpu cyle when the last MMC1 serial write occured</summary>
uint ppuclock; int lastwritecycle;
public override void ClockPPU()
{
ppuclock++;
}
public override void WritePRG(int addr, byte value) public override void WritePRG(int addr, byte value)
{ {
// mmc1 ignores subsequent writes that are very close together // mmc1 ignores subsequent writes that are very close together
if (ppuclock >= pputimeout) if (NES.cpu.TotalExecutedCycles - lastwritecycle != 1)
{ {
ppuclock = 0; lastwritecycle = NES.cpu.TotalExecutedCycles;
mmc1.Write(addr, value); mmc1.Write(addr, value);
if (!disablemirror) if (!disablemirror)
SetMirrorType(mmc1.mirror); //often redundant, but gets the job done SetMirrorType(mmc1.mirror); //often redundant, but gets the job done
@ -271,7 +265,7 @@ namespace BizHawk.Emulation.Consoles.Nintendo
{ {
base.SyncState(ser); base.SyncState(ser);
mmc1.SyncState(ser); mmc1.SyncState(ser);
ser.Sync("ppuclock", ref ppuclock); ser.Sync("lastwritecycle", ref lastwritecycle);
} }
public override bool Configure(NES.EDetectionOrigin origin) public override bool Configure(NES.EDetectionOrigin origin)
@ -365,7 +359,6 @@ namespace BizHawk.Emulation.Consoles.Nintendo
chr_mask = (Cart.chr_size / 8 * 2) - 1; chr_mask = (Cart.chr_size / 8 * 2) - 1;
if (!disablemirror) if (!disablemirror)
SetMirrorType(mmc1.mirror); SetMirrorType(mmc1.mirror);
ppuclock = pputimeout;
} }
} //class SxROM } //class SxROM