Retro/pcjs
Watch
1
0
Fork
You've already forked pcjs
 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

Infrastructure in place for 8080 hardware interrupts (more specifically, vertical retrace interrupts)

Browse source
This commit is contained in:
Jeff Parsons 2016-04-25 18:39:43 -07:00
commit 07259c93ef
17 changed files with 1072 additions and 434 deletions
Download patch file Download diff file Expand all files Collapse all files

35
modules/pc8080/lib/cpu.js
View file

@ -82,6 +82,7 @@ function CPU(parmsCPU, nCyclesDefault)
this.aCounts = {};
this.aCounts.nCyclesPerSecond = nCycles;
this.aCounts.nVideoUpdates = 0;
/*
* nCyclesMultiplier replaces the old "speed" variable (0, 1, 2) and eliminates the need for
@ -148,7 +149,7 @@ Component.subclass(CPU);
* this.aCounts.nCyclesNextStatusUpdate <= this.aCounts.nCyclesPerStatusUpdate
*/
CPU.YIELDS_PER_SECOND = 30;
CPU.VIDEO_UPDATES_PER_SECOND = 60; // WARNING: if you change this, beware of side-effects in the Video component
CPU.VIDEO_UPDATES_PER_SECOND = 60;
CPU.STATUS_UPDATES_PER_SECOND = 2;
CPU.BUTTONS = ["power", "reset"];
@ -173,13 +174,14 @@ CPU.prototype.initBus = function(cmp, bus, cpu, dbg)
if (control) this.cmp.setBinding(null, CPU.BUTTONS[i], control);
}
this.fpu = cmp.getMachineComponent("FPU");
/*
* We need to know the refresh rate (and corresponding interrupt rate, if any) of the Video component.
*/
var video = cmp.getMachineComponent("Video");
this.refreshRate = video && video.getRefreshRate() || CPU.VIDEO_UPDATES_PER_SECOND;
/*
* Attach the ChipSet component to the CPU so that it can obtain the IDT vector number
* of pending hardware interrupts in response to the ChipSet's updateINTR() notifications.
*
* We must also call chipset.updateAllTimers() periodically; stepCPU() takes care of that.
* Attach the ChipSet component to the CPU so that it can be notified whenever the CPU stops and starts.
*/
this.chipset = cmp.getMachineComponent("ChipSet");
@ -197,12 +199,11 @@ CPU.prototype.initBus = function(cmp, bus, cpu, dbg)
/**
* reset()
*
* This is a placeholder for reset (overridden by the CPUSim component).
*
* @this {CPU}
*/
CPU.prototype.reset = function()
{
this.aCounts.nVideoUpdates = 0;
};
/**
@ -550,7 +551,7 @@ CPU.prototype.setBurstCycles = function(nCycles)
* costs are being properly assessed, then we need to update nSnapCycles as well.
*
* TODO: If the delta is negative, we could simply ignore the request, but we must first carefully
* consider the impact on the ChipSet timers.
* consider the impact on the ChipSet timers, if any.
*/
// if (DEBUG) this.nSnapCycles -= nDelta;
this.nStepCycles -= nDelta;
@ -606,7 +607,7 @@ CPU.prototype.calcCycles = function(fRecalc)
* Calculate the most cycles we're allowed to execute in a single "burst"
*/
var nMostUpdatesPerSecond = CPU.YIELDS_PER_SECOND;
if (nMostUpdatesPerSecond < CPU.VIDEO_UPDATES_PER_SECOND) nMostUpdatesPerSecond = CPU.VIDEO_UPDATES_PER_SECOND;
if (nMostUpdatesPerSecond < this.refreshRate) nMostUpdatesPerSecond = this.refreshRate;
if (nMostUpdatesPerSecond < CPU.STATUS_UPDATES_PER_SECOND) nMostUpdatesPerSecond = CPU.STATUS_UPDATES_PER_SECOND;
/*
@ -622,7 +623,7 @@ CPU.prototype.calcCycles = function(fRecalc)
this.aCounts.msPerYield = Math.round(1000 / CPU.YIELDS_PER_SECOND);
this.aCounts.nCyclesPerBurst = Math.floor(this.aCounts.nCyclesPerSecond / nMostUpdatesPerSecond * vMultiplier);
this.aCounts.nCyclesPerYield = Math.floor(this.aCounts.nCyclesPerSecond / CPU.YIELDS_PER_SECOND * vMultiplier);
this.aCounts.nCyclesPerVideoUpdate = Math.floor(this.aCounts.nCyclesPerSecond / CPU.VIDEO_UPDATES_PER_SECOND * vMultiplier);
this.aCounts.nCyclesPerVideoUpdate = Math.floor(this.aCounts.nCyclesPerSecond / this.refreshRate * vMultiplier);
this.aCounts.nCyclesPerStatusUpdate = Math.floor(this.aCounts.nCyclesPerSecond / CPU.STATUS_UPDATES_PER_SECOND * vMultiplier);
/*
@ -807,7 +808,6 @@ CPU.prototype.calcSpeed = function(nCycles, msElapsed)
this.aCounts.mhz = Math.round(nCycles / (msElapsed * 10)) / 100;
if (msElapsed >= 86400000) {
this.nTotalCycles = 0;
if (this.chipset) this.chipset.updateAllTimers(true);
this.setSpeed(); // reset all counters once per day so that we never have to worry about overflow
}
}
@ -965,12 +965,6 @@ CPU.prototype.runCPU = function(fUpdateFocus)
do {
var nCyclesPerBurst = (this.flags.fChecksum? 1 : this.aCounts.nCyclesPerBurst);
if (this.chipset) {
this.chipset.updateAllTimers();
nCyclesPerBurst = this.chipset.getTimerCycleLimit(0, nCyclesPerBurst);
nCyclesPerBurst = this.chipset.getRTCCycleLimit(nCyclesPerBurst);
}
/*
* nCyclesPerBurst is how many cycles we WANT to run on each iteration of stepCPU(), but it may run
* significantly less (or slightly more, since we can't execute partial instructions).
@ -1005,7 +999,8 @@ CPU.prototype.runCPU = function(fUpdateFocus)
this.aCounts.nCyclesNextVideoUpdate -= nCycles;
if (this.aCounts.nCyclesNextVideoUpdate <= 0) {
this.aCounts.nCyclesNextVideoUpdate += this.aCounts.nCyclesPerVideoUpdate;
if (this.cmp) this.cmp.updateVideo();
if (this.cmp) this.cmp.updateVideo(this.aCounts.nVideoUpdates++);
if (this.aCounts.nVideoUpdates > this.refreshRate) this.aCounts.nVideoUpdates = 0;
}
this.aCounts.nCyclesNextStatusUpdate -= nCycles;
@ -1117,7 +1112,7 @@ CPU.prototype.stopCPU = function(fComplete)
CPU.prototype.updateCPU = function(fForce)
{
if (this.cmp) {
this.cmp.updateVideo(fForce);
this.cmp.updateVideo(-1);
this.cmp.updateStatus(fForce);
}
};