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Cleaned up endBurst() and changed yieldCPU() to stop ending bursts prematurely (it only sets the new yield flag now)

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Jeff Parsons 2017-08-14 10:36:10 -07:00 • committed by Jeff Parsons
commit 3d36682396
8 changed files with 524 additions and 538 deletions
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39
modules/pcx86/lib/cpu.js
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@ -963,10 +963,10 @@ class CPU extends Component {
if (fReset || timer[1] < 0) {
nCycles = this.getMSCycles(ms);
/*
* We must now confront the following problem: if the CPU is currently executing a burst of cycles,
* the number of cycles it has executed in that burst so far must NOT be charged against the cycle
* timeout we're about to set. The simplest way to resolve that is to immediately call endBurst()
* and bias the cycle timeout by the number of cycles that the burst executed.
* If the CPU is currently executing a burst of cycles, the number of cycles it has executed in
* that burst so far must NOT be charged against the cycle timeout we're about to set. The simplest
* way to resolve that is to immediately call endBurst() and bias the cycle timeout by the number
* of cycles that the burst executed.
*/
if (this.flags.running) {
nCycles += this.endBurst();
@ -992,10 +992,10 @@ class CPU extends Component {
if (iTimer >= 0 && iTimer < this.aTimers.length) {
var timer = this.aTimers[iTimer];
/*
* We must now confront the following problem: if the CPU is currently executing a burst of cycles,
* the number of cycles it has executed in that burst so far must NOT be charged against the cycle
* timeout we're about to set. The simplest way to resolve that is to immediately call endBurst()
* and bias the cycle timeout by the number of cycles that the burst executed.
* If the CPU is currently executing a burst of cycles, the number of cycles it has executed in
* that burst so far must NOT be charged against the cycle timeout we're about to set. The simplest
* way to resolve that is to immediately call endBurst() and bias the cycle timeout by the number
* of cycles that the burst executed.
*/
if (this.flags.running) {
nCycles += this.endBurst();
@ -1123,17 +1123,17 @@ class CPU extends Component {
}
/**
* endBurst(fReset)
* endBurst()
*
* @this {CPU}
* @param {boolean} [fReset]
* @return {number} (number of cycles executed in the most recent burst)
*/
endBurst(fReset)
endBurst()
{
var nCycles = this.nBurstCycles -= this.nStepCycles;
this.nStepCycles = 0;
if (fReset) this.nBurstCycles = 0;
var nCycles = this.nBurstCycles - this.nStepCycles;
this.nBurstCycles = this.nStepCycles = 0;
this.counts.nCyclesThisRun += nCycles;
this.nRunCycles += nCycles;
return nCycles;
}
@ -1189,19 +1189,13 @@ class CPU extends Component {
/*
* Terminate the burst, returning the number of cycles that stepCPU() actually ran.
*/
nCycles = this.endBurst(true);
/*
* Add nCycles to nCyclesThisRun, as well as nRunCycles (the cycle count since the CPU started).
*/
this.counts.nCyclesThisRun += nCycles;
this.nRunCycles += nCycles;
this.updateChecksum(nCycles);
nCycles = this.endBurst();
/*
* Update all timers, firing those whose cycle countdowns have reached (or dropped below) zero.
*/
this.updateTimers(nCycles);
this.updateChecksum(nCycles);
} while (this.flags.running && !this.flags.yield);
}
@ -1327,7 +1321,6 @@ class CPU extends Component {
*/
yieldCPU()
{
this.endBurst();
this.flags.yield = true;
/*
* The Debugger calls yieldCPU() after every message() to ensure browser responsiveness, but it looks