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Some timer tweaks to improve run repeatability

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Jeff Parsons 2014-11-23 16:57:35 -08:00 • committed by jeffpar
commit 35237a637b
3 changed files with 86 additions and 118 deletions
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27
modules/pcjs/lib/x86cpu.js
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@ -164,7 +164,7 @@ function X86CPU(parmsCPU) {
*/
this.nSamples = 50000;
this.nSampleFreq = 1;
this.nSampleSkip = 3183300;
this.nSampleSkip = 4778000;
this.aSamples = new Array(this.nSamples);
for (var i = 0; i < this.nSamples; i++) this.aSamples[i] = -1;
this.iSampleNext = 0;
@ -1101,7 +1101,7 @@ X86CPU.prototype.save = function()
state.set(0, [this.regAX, this.regBX, this.regCX, this.regDX, this.regSP, this.regBP, this.regSI, this.regDI, this.nIOPL]);
state.set(1, [this.regIP, this.segCS.save(), this.segDS.save(), this.segSS.save(), this.segES.save(), this.saveProtMode(), this.getPS()]);
state.set(2, [this.segData.sName, this.segStack.sName, this.opFlags, this.opPrefixes, this.intFlags, this.regEA, this.regEAWrite]);
state.set(3, [this.nBurstDivisor, this.nTotalCycles, this.getSpeed()]);
state.set(3, [0, this.nTotalCycles, this.getSpeed()]);
state.set(4, this.bus.saveMemory());
return state.data();
};
@ -1143,11 +1143,10 @@ X86CPU.prototype.restore = function(data)
this.opPrefixes = a[3];
this.intFlags = a[4];
this.regEA = a[5];
this.regEAWrite = a[6]; // NOTE: save/restore of prior EA calculation(s) isn't strictly necessary, but they may be of some interest to, say, the Debugger
a = data[3];
this.nBurstDivisor = a[0];
this.regEAWrite = a[6]; // save/restore of last EA calculation(s) isn't strictly necessary, but they may be of some interest to, say, the Debugger
a = data[3]; // a[0] was previously nBurstDivisor (no longer used)
this.nTotalCycles = a[1];
this.setSpeed(a[2]); // If we're restoring an old state that doesn't contain a value from getSpeed(), that's OK; setSpeed() checks for an undefined value
this.setSpeed(a[2]); // if we're restoring an old state that doesn't contain a value from getSpeed(), that's OK; setSpeed() checks for an undefined value
return this.bus.restoreMemory(data[4]);
};
@ -2466,18 +2465,10 @@ X86CPU.prototype.stepCPU = function(nMinCycles)
this.nBurstCycles = this.nStepCycles = nMinCycles;
/*
* NOTE: I have moved updateAllTimers() from runCPU() to here. The effect is exactly the same, except
* that this placement also insures that if the Debugger is doing a lot of single-stepping, all the timers
* will still get updated.
*
* In a typical PC configuration, the timer(s) should be updated a MINIMUM of 18.2 times per second,
* otherwise there's no way to guarantee the standard 18.2 interrupts per second (and in fact, our update
* frequency should probably be a bit higher, otherwise the delivery of timer interrupts may be rather
* uneven). However, I have not yet created a dedicated threshold cycle counter to insure any particular
* timer update rate; I'm currently trusting that the existing update thresholds in the runCPU() function --
* primarily video updates and yields -- will occur frequently enough to provide adequate timer updates.
* NOTE: Even though runCPU() calls updateAllTimers(), we need an additional call here if we're being
* called from the Debugger, so that any single-stepping will update the timers as well.
*/
if (this.chipset) this.chipset.updateAllTimers();
if (this.chipset && !nMinCycles) this.chipset.updateAllTimers();
/*
* Let's also suppress h/w interrupts whenever the Debugger is single-stepping an instruction; I'm loathe
@ -2567,7 +2558,7 @@ X86CPU.prototype.stepCPU = function(nMinCycles)
} else {
this.aSamples[this.iSampleNext] = this.regEIP;
}
if (this.iSampleNext == 112) {
if (this.iSampleNext == 54) {
fDebugSkip = false; // just some no-op statement we can set a breakpoint on
}
this.iSampleNext++;