1247 lines
46 KiB
JavaScript
1247 lines
46 KiB
JavaScript
/**
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* @fileoverview Controls the PC8080 CPU component.
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* @author <a href="mailto:Jeff@pcjs.org">Jeff Parsons</a>
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* @copyright © Jeff Parsons 2012-2017
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*
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* This file is part of PCjs, a computer emulation software project at <http://pcjs.org/>.
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*
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* PCjs is free software: you can redistribute it and/or modify it under the terms of the
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* GNU General Public License as published by the Free Software Foundation, either version 3
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* of the License, or (at your option) any later version.
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*
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* PCjs is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without
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* even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along with PCjs. If not,
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* see <http://www.gnu.org/licenses/gpl.html>.
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*
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* You are required to include the above copyright notice in every modified copy of this work
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* and to display that copyright notice when the software starts running; see COPYRIGHT in
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* <http://pcjs.org/modules/shared/lib/defines.js>.
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*
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* Some PCjs files also attempt to load external resource files, such as character-image files,
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* ROM files, and disk image files. Those external resource files are not considered part of PCjs
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* for purposes of the GNU General Public License, and the author does not claim any copyright
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* as to their contents.
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*/
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"use strict";
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if (NODE) {
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var Str = require("../../shared/lib/strlib");
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var Component = require("../../shared/lib/component");
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var Messages8080 = require("./messages");
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}
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/**
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* TODO: The Closure Compiler treats ES6 classes as 'struct' rather than 'dict' by default,
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* which would force us to declare all class properties in the constructor, as well as prevent
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* us from defining any named properties. So, for now, we mark all our classes as 'unrestricted'.
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*
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* @unrestricted
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*/
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class CPU8080 extends Component {
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/**
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* CPU8080(parmsCPU, nCyclesDefault)
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*
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* The CPU8080 class supports the following (parmsCPU) properties:
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*
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* cycles: the machine's base cycles per second; the CPUState8080 constructor
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* will provide us with a default (based on the CPU model) to use as a fallback.
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*
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* multiplier: base cycle multiplier; default is 1.
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*
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* autoStart: true to automatically start, false to not, or null if "it depends";
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* null is the default, which means do not autostart UNLESS there is no Debugger
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* and no "Run" button (ie, no way to manually start the machine).
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*
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* csStart: the number of cycles that runCPU() must wait before generating
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* checksum records; -1 if disabled. checksum records are a diagnostic aid
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* used to help compare one CPU run to another.
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*
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* csInterval: the number of cycles that runCPU() must execute before generating
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* a checksum record; -1 if disabled.
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*
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* csStop: the number of cycles to stop generating checksum records.
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*
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* This component is primarily responsible for interfacing the CPU with the outside
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* world (eg, Panel and Debugger components), and managing overall CPU operation.
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*
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* It is extended by the CPUState8080 component, where the simulation control logic resides.
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*
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* @this {CPU8080}
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* @param {Object} parmsCPU
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* @param {number} nCyclesDefault
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*/
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constructor(parmsCPU, nCyclesDefault)
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{
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super("CPU", parmsCPU, Messages8080.CPU);
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var nCycles = parmsCPU['cycles'] || nCyclesDefault;
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var nMultiplier = parmsCPU['multiplier'] || 1;
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this.nCyclesPerSecond = nCycles;
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/*
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* nCyclesMultiplier replaces the old "speed" variable (0, 1, 2) and eliminates the need for
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* the constants (SPEED_SLOW, SPEED_FAST and SPEED_MAX). The UI simply doubles the multiplier
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* until we've exceeded the host's speed limit and then starts the multiplier over at 1.
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*/
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this.nCyclesMultiplier = nMultiplier;
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this.mhzDefault = Math.round(this.nCyclesPerSecond / 10000) / 100;
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/*
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* TODO: Take care of this with an initial setSpeed() call instead?
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*/
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this.mhzTarget = this.mhzDefault * this.nCyclesMultiplier;
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/*
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* We add a number of flags to the set initialized by Component
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*/
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this.flags.running = false;
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this.flags.starting = false;
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this.flags.autoStart = parmsCPU['autoStart'];
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/*
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* TODO: Add some UI for fDisplayLiveRegs (either an XML property, or a UI checkbox, or both)
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*/
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this.flags.displayLiveRegs = false;
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/*
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* Get checksum parameters, if any. runCPU() behavior is not affected until fChecksum
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* is true, which won't happen until resetChecksum() is called with nCyclesChecksumInterval
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* ("csInterval") set to a positive value.
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*
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* As above, any of these parameters can also be set with the Debugger's execution options
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* command ("x"); for example, "x cs int 5000" will set nCyclesChecksumInterval to 5000
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* and call resetChecksum().
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*/
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this.flags.checksum = false;
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this.nChecksum = this.nCyclesChecksumNext = 0;
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this.nCyclesChecksumStart = parmsCPU["csStart"];
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this.nCyclesChecksumInterval = parmsCPU["csInterval"];
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this.nCyclesChecksumStop = parmsCPU["csStop"];
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/*
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* Array of countdown timers managed by addTimer() and setTimer().
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*/
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this.aTimers = [];
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this.onRunTimeout = this.runCPU.bind(this); // function onRunTimeout() { cpu.runCPU(); };
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this.setReady();
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}
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/**
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* initBus(cmp, bus, cpu, dbg)
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*
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* @this {CPU8080}
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* @param {Computer8080} cmp
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* @param {Bus8080} bus
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* @param {CPU8080} cpu
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* @param {Debugger8080} dbg
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*/
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initBus(cmp, bus, cpu, dbg)
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{
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this.cmp = cmp;
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this.bus = bus;
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this.dbg = dbg;
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for (var i = 0; i < CPU8080.BUTTONS.length; i++) {
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var control = this.bindings[CPU8080.BUTTONS[i]];
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if (control) this.cmp.setBinding(null, CPU8080.BUTTONS[i], control);
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}
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/*
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* Attach the ChipSet component to the CPU so that it can be notified whenever the CPU stops and starts.
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*/
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this.chipset = /** @type {ChipSet8080} */ (cmp.getMachineComponent("ChipSet"));
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/*
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* We've already saved the parmsCPU 'autoStart' setting, but there may be a machine (or URL) override.
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*/
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var sAutoStart = cmp.getMachineParm('autoStart');
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if (sAutoStart != null) {
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this.flags.autoStart = (sAutoStart == "true"? true : (sAutoStart == "false"? false : !!sAutoStart));
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}
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this.setReady();
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}
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/**
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* reset()
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*
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* @this {CPU8080}
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*/
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reset()
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{
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}
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/**
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* save()
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*
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* This is a placeholder for save support (overridden by the CPUState8080 component).
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*
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* @this {CPU8080}
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* @return {Object|null}
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*/
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save()
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{
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return null;
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}
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/**
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* restore(data)
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*
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* This is a placeholder for restore support (overridden by the CPUState8080 component).
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*
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* @this {CPU8080}
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* @param {Object} data
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* @return {boolean} true if restore successful, false if not
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*/
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restore(data)
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{
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return false;
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}
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/**
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* powerUp(data, fRepower)
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*
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* @this {CPU8080}
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* @param {Object|null} data
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* @param {boolean} [fRepower]
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* @return {boolean} true if successful, false if failure
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*/
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powerUp(data, fRepower)
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{
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if (!fRepower) {
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if (!data || !this.restore) {
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this.reset();
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} else {
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this.resetCycles();
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if (!this.restore(data)) return false;
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this.resetChecksum();
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}
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/*
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* Give the Debugger a chance to do/print something once we've powered up
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*/
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if (DEBUGGER && this.dbg) {
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this.dbg.init();
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} else {
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this.println("No debugger detected");
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}
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}
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/*
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* The Computer component (which is responsible for all powerDown and powerUp notifications)
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* is now responsible for managing a component's fPowered flag, not us.
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*
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* this.flags.powered = true;
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*/
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this.updateCPU();
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return true;
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}
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/**
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* powerDown(fSave, fShutdown)
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*
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* @this {CPU8080}
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* @param {boolean} [fSave]
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* @param {boolean} [fShutdown]
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* @return {Object|boolean} component state if fSave; otherwise, true if successful, false if failure
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*/
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powerDown(fSave, fShutdown)
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{
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/*
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* The Computer component (which is responsible for all powerDown and powerUp notifications)
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* is now responsible for managing a component's fPowered flag, not us.
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*
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* this.flags.powered = false;
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*/
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return fSave? this.save() : true;
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}
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/**
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* autoStart()
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*
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* @this {CPU8080}
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* @return {boolean} true if started, false if not
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*/
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autoStart()
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{
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/*
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* Start running automatically on power-up, assuming there's no Debugger and no "Run" button
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*/
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if (this.flags.autoStart || (!DEBUGGER || !this.dbg) && this.bindings["run"] === undefined) {
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/*
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* We used to also set fUpdateFocus when calling runCPU(), on the assumption that in the "auto-starting"
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* context, a machine without focus is like a day without sunshine, but in reality, focus should only be
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* forced when the user takes some other machine-related action.
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*/
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this.runCPU();
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return true;
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}
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return false;
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}
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/**
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* isPowered()
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*
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* @this {CPU8080}
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* @return {boolean}
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*/
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isPowered()
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{
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if (!this.flags.powered) {
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this.println(this.toString() + " not powered");
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return false;
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}
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return true;
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}
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/**
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* isRunning()
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*
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* @this {CPU8080}
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* @return {boolean}
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*/
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isRunning()
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{
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return this.flags.running;
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}
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/**
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* getChecksum()
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*
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* This will be implemented by the CPUState8080 component.
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*
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* @this {CPU8080}
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* @return {number} a 32-bit summation of key elements of the current CPU state (used by the CPU checksum code)
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*/
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getChecksum()
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{
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return 0;
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}
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/**
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* resetChecksum()
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*
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* If checksum generation is enabled (fChecksum is true), this resets the running 32-bit checksum and the
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* cycle counter that will trigger the next displayChecksum(); called by resetCycles(), which is called whenever
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* the CPU is reset or restored.
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*
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* @this {CPU8080}
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* @return {boolean} true if checksum generation enabled, false if not
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*/
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resetChecksum()
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{
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if (this.nCyclesChecksumStart === undefined) this.nCyclesChecksumStart = 0;
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if (this.nCyclesChecksumInterval === undefined) this.nCyclesChecksumInterval = -1;
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if (this.nCyclesChecksumStop === undefined) this.nCyclesChecksumStop = -1;
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this.flags.checksum = (this.nCyclesChecksumStart >= 0 && this.nCyclesChecksumInterval > 0);
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if (this.flags.checksum) {
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this.nChecksum = 0;
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this.nCyclesChecksumNext = this.nCyclesChecksumStart - this.nTotalCycles;
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/*
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* this.nCyclesChecksumNext = this.nCyclesChecksumStart + this.nCyclesChecksumInterval -
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* (this.nTotalCycles % this.nCyclesChecksumInterval);
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*/
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return true;
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}
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return false;
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}
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/**
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* updateChecksum(nCycles)
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*
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* When checksum generation is enabled (fChecksum is true), runCPU() asks stepCPU() to execute a minimum
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* number of cycles (1), effectively limiting execution to a single instruction, and then we're called with
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* the exact number cycles that were actually executed. This should give us instruction-granular checksums
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* at precise intervals that are 100% repeatable.
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*
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* @this {CPU8080}
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* @param {number} nCycles
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*/
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updateChecksum(nCycles)
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{
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if (this.flags.checksum) {
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/*
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* Get a 32-bit summation of the current CPU state and add it to our running 32-bit checksum
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*/
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var fDisplay = false;
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this.nChecksum = (this.nChecksum + this.getChecksum())|0;
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this.nCyclesChecksumNext -= nCycles;
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if (this.nCyclesChecksumNext <= 0) {
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this.nCyclesChecksumNext += this.nCyclesChecksumInterval;
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fDisplay = true;
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}
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if (this.nCyclesChecksumStop >= 0) {
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if (this.nCyclesChecksumStop <= this.getCycles()) {
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this.nCyclesChecksumInterval = this.nCyclesChecksumStop = -1;
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this.resetChecksum();
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this.stopCPU();
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fDisplay = true;
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}
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}
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if (fDisplay) this.displayChecksum();
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}
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}
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/**
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* displayChecksum()
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*
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* When checksum generation is enabled (fChecksum is true), this is called to provide a crude log of all
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* checksums generated at the specified cycle intervals, as specified by the "csStart" and "csInterval" parmsCPU
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* properties).
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*
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* @this {CPU8080}
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*/
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displayChecksum()
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{
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this.println(this.getCycles() + " cycles: " + "checksum=" + Str.toHex(this.nChecksum));
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}
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/**
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* displayValue(sLabel, nValue, cch)
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*
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* This is principally for displaying register values, but in reality, it can be used to display any
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* numeric (hex) value bound to the given label.
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*
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* @this {CPU8080}
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* @param {string} sLabel
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* @param {number} nValue
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* @param {number} cch
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*/
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displayValue(sLabel, nValue, cch)
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{
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if (this.bindings[sLabel]) {
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if (nValue === undefined) {
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this.setError("Value for " + sLabel + " is invalid");
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this.stopCPU();
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}
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var sVal;
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if (!this.flags.running || this.flags.displayLiveRegs) {
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sVal = Str.toHex(nValue, cch);
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} else {
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sVal = "--------".substr(0, cch);
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}
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/*
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* TODO: Determine if this test actually avoids any redrawing when a register hasn't changed, and/or if
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* we should maintain our own (numeric) cache of displayed register values (to avoid creating these temporary
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* string values that will have to garbage-collected), and/or if this is actually slower, and/or if I'm being
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* too obsessive.
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*/
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if (this.bindings[sLabel].textContent != sVal) this.bindings[sLabel].textContent = sVal;
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}
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}
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/**
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* setBinding(sHTMLType, sBinding, control, sValue)
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*
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* @this {CPU8080}
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* @param {string|null} sHTMLType is the type of the HTML control (eg, "button", "list", "text", "submit", "textarea", "canvas")
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* @param {string} sBinding is the value of the 'binding' parameter stored in the HTML control's "data-value" attribute (eg, "run")
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* @param {Object} control is the HTML control DOM object (eg, HTMLButtonElement)
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* @param {string} [sValue] optional data value
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* @return {boolean} true if binding was successful, false if unrecognized binding request
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*/
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setBinding(sHTMLType, sBinding, control, sValue)
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{
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var cpu = this;
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var fBound = false;
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switch (sBinding) {
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case "power":
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case "reset":
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/*
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* The "power" and "reset" buttons are functions of the entire computer, not just the CPU,
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* but it's not always convenient to stick a power button in the Computer component definition,
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* so we record those bindings here and pass them on to the Computer component in initBus().
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*/
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this.bindings[sBinding] = control;
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fBound = true;
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break;
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case "run":
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this.bindings[sBinding] = control;
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control.onclick = function onClickRun() {
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if (!cpu.cmp || !cpu.cmp.checkPower()) return;
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/*
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* We no longer pass true to these runCPU()/stopCPU() calls, on the theory that if the "run"
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* control is visible, then the computer is probably sufficiently visible as well; the problem
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* with setting fUpdateFocus to true is that it can jerk the web page around in annoying ways.
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*/
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if (!cpu.flags.running)
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cpu.runCPU();
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else
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cpu.stopCPU();
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};
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fBound = true;
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break;
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case "speed":
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this.bindings[sBinding] = control;
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fBound = true;
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break;
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case "setSpeed":
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this.bindings[sBinding] = control;
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control.onclick = function onClickSetSpeed() {
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cpu.setSpeed(cpu.nCyclesMultiplier << 1, true);
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};
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control.textContent = this.getSpeedTarget();
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fBound = true;
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break;
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default:
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break;
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}
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return fBound;
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}
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|
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/**
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* setBurstCycles(nCycles)
|
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*
|
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* This function is used by the ChipSet component whenever a very low timer count is set,
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* in anticipation of the timer requiring an update sooner than the normal nCyclesPerYield
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* period in runCPU() would normally provide.
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*
|
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* NOTE: In this context, "timer" refers to a timer chip (eg, an Intel 8253) being emulated by
|
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* by the ChipSet component, not the timers managed by the CPU (eg, addTimer(), setTimer(), etc).
|
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*
|
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* @this {CPU8080}
|
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* @param {number} nCycles is the target number of cycles to drop the current burst to
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* @return {boolean}
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*/
|
|
setBurstCycles(nCycles)
|
|
{
|
|
if (this.flags.running) {
|
|
var nDelta = this.nStepCycles - nCycles;
|
|
/*
|
|
* NOTE: If nDelta is negative, we will actually be increasing nStepCycles and nBurstCycles.
|
|
* Which is OK, but if we're also taking snapshots of the cycle counts, to make sure that instruction
|
|
* 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, if any.
|
|
*/
|
|
// if (DEBUG) this.nSnapCycles -= nDelta;
|
|
this.nStepCycles -= nDelta;
|
|
this.nBurstCycles -= nDelta;
|
|
return true;
|
|
}
|
|
return false;
|
|
}
|
|
|
|
/**
|
|
* addCycles(nCycles, fEndStep)
|
|
*
|
|
* @this {CPU8080}
|
|
* @param {number} nCycles
|
|
* @param {boolean} [fEndStep]
|
|
*/
|
|
addCycles(nCycles, fEndStep)
|
|
{
|
|
this.nTotalCycles += nCycles;
|
|
if (fEndStep) {
|
|
this.nBurstCycles = this.nStepCycles = 0;
|
|
}
|
|
}
|
|
|
|
/**
|
|
* calcCycles(fRecalc)
|
|
*
|
|
* Calculate the number of cycles to process for each "burst" of CPU activity. The size of a burst
|
|
* is driven by YIELDS_PER_SECOND (eg, 30).
|
|
*
|
|
* At the end of each burst, we subtract burst cycles from the yield cycle "threshold" counter.
|
|
* Whenever the "next yield" cycle counter goes to (or below) zero, we compare elapsed time to the time
|
|
* we expected the virtual hardware to take (eg, 1000ms/50 or 20ms), and if we still have time remaining,
|
|
* we sleep the remaining time (or 0ms if there's no remaining time), and then restart runCPU().
|
|
*
|
|
* @this {CPU8080}
|
|
* @param {boolean} [fRecalc] is true if the caller wants to recalculate thresholds based on the most recent
|
|
* speed calculation (see calcSpeed).
|
|
*/
|
|
calcCycles(fRecalc)
|
|
{
|
|
/*
|
|
* Calculate "per" yield values.
|
|
*/
|
|
var vMultiplier = 1;
|
|
if (fRecalc) {
|
|
if (this.nCyclesMultiplier > 1 && this.mhz) {
|
|
vMultiplier = (this.mhz / this.mhzDefault);
|
|
}
|
|
}
|
|
|
|
this.msPerYield = Math.round(1000 / CPU8080.YIELDS_PER_SECOND);
|
|
this.nCyclesPerYield = Math.floor(this.nCyclesPerSecond / CPU8080.YIELDS_PER_SECOND * vMultiplier);
|
|
|
|
/*
|
|
* And initialize "next" yield values to the "per" values.
|
|
*/
|
|
if (!fRecalc) {
|
|
this.nCyclesNextYield = this.nCyclesPerYield;
|
|
}
|
|
this.nCyclesRecalc = 0;
|
|
}
|
|
|
|
/**
|
|
* getCycles(fScaled)
|
|
*
|
|
* getCycles() returns the number of cycles executed so far. Note that we can be called after
|
|
* runCPU() OR during runCPU(), perhaps from a handler triggered during the current run's stepCPU(),
|
|
* so nRunCycles must always be adjusted by number of cycles stepCPU() was asked to run (nBurstCycles),
|
|
* less the number of cycles it has yet to run (nStepCycles).
|
|
*
|
|
* nRunCycles is zeroed whenever the CPU is halted or the CPU speed is changed, which is why we also
|
|
* have nTotalCycles, which accumulates all nRunCycles before we zero it. However, nRunCycles and
|
|
* nTotalCycles eventually get reset by calcSpeed(), to avoid overflow, so components that rely on
|
|
* getCycles() returning steadily increasing values should also be prepared for a reset at any time.
|
|
*
|
|
* @this {CPU8080}
|
|
* @param {boolean} [fScaled] is true if the caller wants a cycle count relative to a multiplier of 1
|
|
* @return {number}
|
|
*/
|
|
getCycles(fScaled)
|
|
{
|
|
var nCycles = this.nTotalCycles + this.nRunCycles + this.nBurstCycles - this.nStepCycles;
|
|
if (fScaled && this.nCyclesMultiplier > 1 && this.mhz > this.mhzDefault) {
|
|
/*
|
|
* We could scale the current cycle count by the current effective speed (this.mhz); eg:
|
|
*
|
|
* nCycles = Math.round(nCycles / (this.mhz / this.mhzDefault));
|
|
*
|
|
* but that speed will fluctuate somewhat: large fluctuations at first, but increasingly smaller
|
|
* fluctuations after each burst of instructions that runCPU() executes.
|
|
*
|
|
* Alternatively, we can scale the cycle count by the multiplier, which is good in that the
|
|
* multiplier doesn't vary once the user changes it, but a potential downside is that the
|
|
* multiplier might be set too high, resulting in a target speed that's higher than the effective
|
|
* speed is able to reach.
|
|
*
|
|
* Also, if multipliers were always limited to a power-of-two, then this could be calculated
|
|
* with a simple shift. However, only the "setSpeed" UI binding limits it that way; the Debugger
|
|
* interface allows any value, as does the CPU "multiplier" parmsCPU property (from the machine's
|
|
* XML file).
|
|
*/
|
|
nCycles = Math.round(nCycles / this.nCyclesMultiplier);
|
|
}
|
|
return nCycles;
|
|
}
|
|
|
|
/**
|
|
* getCyclesPerSecond()
|
|
*
|
|
* This returns the CPU's "base" speed (ie, the original cycles per second defined for the machine)
|
|
*
|
|
* @this {CPU8080}
|
|
* @return {number}
|
|
*/
|
|
getCyclesPerSecond()
|
|
{
|
|
return this.nCyclesPerSecond;
|
|
}
|
|
|
|
/**
|
|
* resetCycles()
|
|
*
|
|
* Resets speed and cycle information as part of any reset() or restore(); this typically occurs during powerUp().
|
|
* It's important that this be called BEFORE the actual restore() call, because restore() may want to call setSpeed(),
|
|
* which in turn assumes that all the cycle counts have been initialized to sensible values.
|
|
*
|
|
* @this {CPU8080}
|
|
*/
|
|
resetCycles()
|
|
{
|
|
this.mhz = 0;
|
|
this.nYieldsSinceStatusUpdate = 0;
|
|
this.nTotalCycles = this.nRunCycles = this.nBurstCycles = this.nStepCycles = 0;
|
|
this.resetChecksum();
|
|
this.setSpeed(1);
|
|
}
|
|
|
|
/**
|
|
* getSpeed()
|
|
*
|
|
* @this {CPU8080}
|
|
* @return {number} the current speed multiplier
|
|
*/
|
|
getSpeed()
|
|
{
|
|
return this.nCyclesMultiplier;
|
|
}
|
|
|
|
/**
|
|
* getSpeedCurrent()
|
|
*
|
|
* @this {CPU8080}
|
|
* @return {string} the current speed, in mhz, as a string formatted to two decimal places
|
|
*/
|
|
getSpeedCurrent()
|
|
{
|
|
/*
|
|
* TODO: Has toFixed() been "fixed" in all browsers (eg, IE) to return a rounded value now?
|
|
*/
|
|
return ((this.flags.running && this.mhz)? (this.mhz.toFixed(2) + "Mhz") : "Stopped");
|
|
}
|
|
|
|
/**
|
|
* getSpeedTarget()
|
|
*
|
|
* @this {CPU8080}
|
|
* @return {string} the target speed, in mhz, as a string formatted to two decimal places
|
|
*/
|
|
getSpeedTarget()
|
|
{
|
|
/*
|
|
* TODO: Has toFixed() been "fixed" in all browsers (eg, IE) to return a rounded value now?
|
|
*/
|
|
return this.mhzTarget.toFixed(2) + "Mhz";
|
|
}
|
|
|
|
/**
|
|
* setSpeed(nMultiplier, fUpdateFocus)
|
|
*
|
|
* NOTE: This used to return the target speed, in mhz, but no callers appear to care at this point.
|
|
*
|
|
* @desc Whenever the speed is changed, the running cycle count and corresponding start time must be reset,
|
|
* so that the next effective speed calculation obtains sensible results. In fact, when runCPU() initially calls
|
|
* setSpeed() with no parameters, that's all this function does (it doesn't change the current speed setting).
|
|
*
|
|
* @this {CPU8080}
|
|
* @param {number} [nMultiplier] is the new proposed multiplier (reverts to 1 if the target was too high)
|
|
* @param {boolean} [fUpdateFocus] is true to update Computer focus
|
|
* @return {boolean} true if successful, false if not
|
|
*/
|
|
setSpeed(nMultiplier, fUpdateFocus)
|
|
{
|
|
var fSuccess = false;
|
|
if (nMultiplier !== undefined) {
|
|
/*
|
|
* If we haven't reached 80% (0.8) of the current target speed, revert to a multiplier of one (1).
|
|
*/
|
|
if (this.mhz / this.mhzTarget < 0.8) {
|
|
nMultiplier = 1;
|
|
} else {
|
|
fSuccess = true;
|
|
}
|
|
this.nCyclesMultiplier = nMultiplier;
|
|
var mhz = this.mhzDefault * this.nCyclesMultiplier;
|
|
if (this.mhzTarget != mhz) {
|
|
this.mhzTarget = mhz;
|
|
var sSpeed = this.getSpeedTarget();
|
|
var controlSpeed = this.bindings["setSpeed"];
|
|
if (controlSpeed) controlSpeed.textContent = sSpeed;
|
|
this.println("target speed: " + sSpeed);
|
|
}
|
|
if (fUpdateFocus && this.cmp) this.cmp.updateFocus();
|
|
}
|
|
this.addCycles(this.nRunCycles);
|
|
this.nRunCycles = 0;
|
|
this.msStartRun = Component.getTime();
|
|
this.msEndThisRun = 0;
|
|
this.calcCycles();
|
|
return fSuccess;
|
|
}
|
|
|
|
/**
|
|
* calcSpeed(nCycles, msElapsed)
|
|
*
|
|
* @this {CPU8080}
|
|
* @param {number} nCycles
|
|
* @param {number} msElapsed
|
|
*/
|
|
calcSpeed(nCycles, msElapsed)
|
|
{
|
|
if (msElapsed) {
|
|
this.mhz = Math.round(nCycles / (msElapsed * 10)) / 100;
|
|
if (msElapsed >= 86400000) {
|
|
this.nTotalCycles = 0;
|
|
this.setSpeed(); // reset all counters once per day so that we never have to worry about overflow
|
|
}
|
|
}
|
|
}
|
|
|
|
/**
|
|
* calcStartTime()
|
|
*
|
|
* @this {CPU8080}
|
|
*/
|
|
calcStartTime()
|
|
{
|
|
if (this.nCyclesRecalc >= this.nCyclesPerSecond) {
|
|
this.calcCycles(true);
|
|
}
|
|
this.nCyclesThisRun = 0;
|
|
this.msStartThisRun = Component.getTime();
|
|
|
|
/*
|
|
* Try to detect situations where the browser may have throttled us, such as when the user switches
|
|
* to a different tab; in those situations, Chrome and Safari may restrict setTimeout() callbacks
|
|
* to roughly one per second.
|
|
*
|
|
* Another scenario: the user resizes the browser window. setTimeout() callbacks are not throttled,
|
|
* but there can still be enough of a lag between the callbacks that CPU speed will be noticeably
|
|
* erratic if we don't compensate for it here.
|
|
*
|
|
* We can detect throttling/lagging by verifying that msEndThisRun (which was set at the end of the
|
|
* previous run and includes any requested sleep time) is comparable to the current msStartThisRun;
|
|
* if the delta is significant, we compensate by bumping msStartRun forward by that delta.
|
|
*
|
|
* This shouldn't be triggered when the Debugger halts the CPU, because setSpeed() -- which is called
|
|
* whenever the CPU starts running again -- zeroes msEndThisRun.
|
|
*
|
|
* This also won't do anything about other internal delays; for example, Debugger message() calls.
|
|
* By the time the message() function has called yieldCPU(), the cost of the message has already been
|
|
* incurred, so it will be end up being charged against the instruction(s) that triggered it.
|
|
*
|
|
* TODO: Consider calling yieldCPU() sooner from message(), so that it can arrange for the msEndThisRun
|
|
* "snapshot" to occur sooner; it's unclear, however, whether that will really improve the CPU's ability
|
|
* to hit its target speed, since you would expect any instruction that displays a message to be an
|
|
* EXTREMELY slow instruction.
|
|
*/
|
|
if (this.msEndThisRun) {
|
|
var msDelta = this.msStartThisRun - this.msEndThisRun;
|
|
if (msDelta > this.msPerYield) {
|
|
if (MAXDEBUG) this.println("large time delay: " + msDelta + "ms");
|
|
this.msStartRun += msDelta;
|
|
/*
|
|
* Bumping msStartRun forward should NEVER cause it to exceed msStartThisRun; however, just
|
|
* in case, I make absolutely sure it cannot happen, since doing so could result in negative
|
|
* speed calculations.
|
|
*/
|
|
this.assert(this.msStartRun <= this.msStartThisRun);
|
|
if (this.msStartRun > this.msStartThisRun) {
|
|
this.msStartRun = this.msStartThisRun;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/**
|
|
* calcRemainingTime()
|
|
*
|
|
* @this {CPU8080}
|
|
* @return {number}
|
|
*/
|
|
calcRemainingTime()
|
|
{
|
|
this.msEndThisRun = Component.getTime();
|
|
|
|
var msYield = this.msPerYield;
|
|
if (this.nCyclesThisRun) {
|
|
/*
|
|
* Normally, we would assume we executed a full quota of work over msPerYield, but since the CPU
|
|
* now has the option of calling yieldCPU(), that might not be true. If nCyclesThisRun is correct, then
|
|
* the ratio of nCyclesThisRun/nCyclesPerYield should represent the percentage of work we performed,
|
|
* and so applying that percentage to msPerYield should give us a better estimate of work vs. time.
|
|
*/
|
|
msYield = Math.round(msYield * this.nCyclesThisRun / this.nCyclesPerYield);
|
|
}
|
|
|
|
var msElapsedThisRun = this.msEndThisRun - this.msStartThisRun;
|
|
var msRemainsThisRun = msYield - msElapsedThisRun;
|
|
|
|
/*
|
|
* We could pass only "this run" results to calcSpeed():
|
|
*
|
|
* nCycles = this.nCyclesThisRun;
|
|
* msElapsed = msElapsedThisRun;
|
|
*
|
|
* but it seems preferable to use longer time periods and hopefully get a more accurate speed.
|
|
*
|
|
* Also, if msRemainsThisRun >= 0 && this.nCyclesMultiplier == 1, we could pass these results instead:
|
|
*
|
|
* nCycles = this.nCyclesThisRun;
|
|
* msElapsed = this.msPerYield;
|
|
*
|
|
* to insure that we display a smooth, constant N Mhz. But for now, I prefer seeing any fluctuations.
|
|
*/
|
|
var nCycles = this.nRunCycles;
|
|
var msElapsed = this.msEndThisRun - this.msStartRun;
|
|
|
|
if (MAXDEBUG && msRemainsThisRun < 0 && this.nCyclesMultiplier > 1) {
|
|
this.println("warning: updates @" + msElapsedThisRun + "ms (prefer " + Math.round(msYield) + "ms)");
|
|
}
|
|
|
|
this.calcSpeed(nCycles, msElapsed);
|
|
|
|
if (msRemainsThisRun < 0 || this.mhz < this.mhzTarget) {
|
|
/*
|
|
* Try "throwing out" the effects of large anomalies, by moving the overall run start time up;
|
|
* ordinarily, this should only happen when the someone is using an external Debugger or some other
|
|
* tool or feature that is interfering with our overall execution.
|
|
*/
|
|
if (msRemainsThisRun < -1000) {
|
|
this.msStartRun -= msRemainsThisRun;
|
|
}
|
|
/*
|
|
* If the last burst took MORE time than we allotted (ie, it's taking more than 1 second to simulate
|
|
* nCyclesPerSecond), all we can do is yield for as little time as possible (ie, 0ms) and hope that the
|
|
* simulation is at least usable.
|
|
*/
|
|
msRemainsThisRun = 0;
|
|
}
|
|
|
|
/*
|
|
* Last but not least, update nCyclesRecalc, so that when runCPU() starts up again and calls calcStartTime(),
|
|
* it'll be ready to decide if calcCycles() should be called again.
|
|
*/
|
|
this.nCyclesRecalc += this.nCyclesThisRun;
|
|
|
|
if (DEBUG && this.messageEnabled(Messages8080.LOG) && msRemainsThisRun) {
|
|
this.log("calcRemainingTime: " + msRemainsThisRun + "ms to sleep after " + this.msEndThisRun + "ms");
|
|
}
|
|
|
|
this.msEndThisRun += msRemainsThisRun;
|
|
return msRemainsThisRun;
|
|
}
|
|
|
|
/**
|
|
* addTimer(callBack)
|
|
*
|
|
* Components that want to have timers that periodically fire after some number of milliseconds call
|
|
* addTimer() to create the timer, and then setTimer() every time they want to arm it. There is currently
|
|
* no removeTimer() because these are generally used for the entire lifetime of a component.
|
|
*
|
|
* Internally, each timer entry is a preallocated Array with two entries: a cycle countdown in element [0]
|
|
* and a callback function in element [1]. A timer is initially dormant; dormant timers have a countdown
|
|
* value of -1 (although any negative number will suffice) and active timers have a non-negative value.
|
|
*
|
|
* Why not use JavaScript's setTimeout() instead? Good question. For a good answer, see setTimer() below.
|
|
*
|
|
* @this {CPU8080}
|
|
* @param {function()} callBack
|
|
* @return {number} timer index
|
|
*/
|
|
addTimer(callBack)
|
|
{
|
|
var iTimer = this.aTimers.length;
|
|
this.aTimers.push([-1, callBack]);
|
|
return iTimer;
|
|
}
|
|
|
|
/**
|
|
* setTimer(iTimer, ms, fReset)
|
|
*
|
|
* Using the timer index from a previous addTimer() call, this sets that timer to fire after the
|
|
* specified number of milliseconds.
|
|
*
|
|
* This is preferred over JavaScript's setTimeout(), because all our timers are effectively paused when
|
|
* the CPU is paused (eg, when the Debugger halts execution). Moreover, setTimeout() handlers only run after
|
|
* runCPU() yields, which is far too granular for some components (eg, when the SerialPort tries to simulate
|
|
* interrupts at 9600 baud).
|
|
*
|
|
* Ideally, the only function that would use setTimeout() is runCPU(), while the rest of the components
|
|
* use setTimer(); however, due to legacy code (ie, code that predates these functions) and/or laziness,
|
|
* that's currently not the case. TODO: Fix.
|
|
*
|
|
* @this {CPU8080}
|
|
* @param {number} iTimer
|
|
* @param {number} ms (converted into a cycle countdown internally)
|
|
* @param {boolean} [fReset] (true if the timer should be reset even if already armed)
|
|
* @return {number} (number of cycles used to arm timer, or -1 if error)
|
|
*/
|
|
setTimer(iTimer, ms, fReset)
|
|
{
|
|
var nCycles = -1;
|
|
if (iTimer >= 0 && iTimer < this.aTimers.length) {
|
|
if (fReset || this.aTimers[iTimer][0] < 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 above cycle timeout by the number of cycles that the burst executed.
|
|
*/
|
|
if (this.flags.running) {
|
|
nCycles += this.endBurst();
|
|
}
|
|
this.aTimers[iTimer][0] = nCycles;
|
|
}
|
|
}
|
|
return nCycles;
|
|
}
|
|
|
|
/**
|
|
* getMSCycles(ms)
|
|
*
|
|
* @this {CPU8080}
|
|
* @param {number} ms
|
|
* @return {number} number of corresponding cycles
|
|
*/
|
|
getMSCycles(ms)
|
|
{
|
|
return ((this.nCyclesPerSecond * this.nCyclesMultiplier) / 1000 * ms)|0;
|
|
}
|
|
|
|
/**
|
|
* getBurstCycles(nCycles)
|
|
*
|
|
* Used by runCPU() to get min(nCycles,[timer cycle counts])
|
|
*
|
|
* @this {CPU8080}
|
|
* @param {number} nCycles (number of cycles about to execute)
|
|
* @return {number} (either nCycles or less if a timer needs to fire)
|
|
*/
|
|
getBurstCycles(nCycles)
|
|
{
|
|
for (var i = this.aTimers.length - 1; i >= 0; i--) {
|
|
var timer = this.aTimers[i];
|
|
this.assert(!isNaN(timer[0]));
|
|
if (timer[0] < 0) continue;
|
|
if (nCycles > timer[0]) {
|
|
nCycles = timer[0];
|
|
}
|
|
}
|
|
return nCycles;
|
|
}
|
|
|
|
/**
|
|
* updateTimers(nCycles)
|
|
*
|
|
* Used by runCPU() to reduce all active timer countdown values by the number of cycles just executed;
|
|
* this is the function that actually "fires" any timer(s) whose countdown has reached (or dropped below)
|
|
* zero, invoking their callback function.
|
|
*
|
|
* @this {CPU8080}
|
|
* @param {number} nCycles (number of cycles actually executed)
|
|
*/
|
|
updateTimers(nCycles)
|
|
{
|
|
for (var i = this.aTimers.length - 1; i >= 0; i--) {
|
|
var timer = this.aTimers[i];
|
|
this.assert(!isNaN(timer[0]));
|
|
if (timer[0] < 0) continue;
|
|
timer[0] -= nCycles;
|
|
if (timer[0] <= 0) {
|
|
timer[0] = -1; // zero is technically an "active" value, so ensure the timer is dormant now
|
|
timer[1](); // safe to invoke the callback function now
|
|
}
|
|
}
|
|
}
|
|
|
|
/**
|
|
* endBurst(fReset)
|
|
*
|
|
* @this {CPU8080}
|
|
* @param {boolean} [fReset]
|
|
* @return {number} (number of cycles executed in the most recent burst)
|
|
*/
|
|
endBurst(fReset)
|
|
{
|
|
var nCycles = this.nBurstCycles -= this.nStepCycles;
|
|
this.nStepCycles = 0;
|
|
if (fReset) this.nBurstCycles = 0;
|
|
return nCycles;
|
|
}
|
|
|
|
/**
|
|
* runCPU(fUpdateFocus)
|
|
*
|
|
* @this {CPU8080}
|
|
* @param {boolean} [fUpdateFocus] is true to update Computer focus
|
|
*/
|
|
runCPU(fUpdateFocus)
|
|
{
|
|
if (!this.setBusy(true)) {
|
|
this.updateCPU();
|
|
if (this.cmp) this.cmp.stop(Component.getTime(), this.getCycles());
|
|
return;
|
|
}
|
|
|
|
this.startCPU(fUpdateFocus);
|
|
|
|
/*
|
|
* calcStartTime() initializes the cycle counter and timestamp for this runCPU() invocation, and optionally
|
|
* recalculates the the maximum number of cycles for each burst if the nCyclesRecalc threshold has been reached.
|
|
*/
|
|
this.calcStartTime();
|
|
|
|
try {
|
|
do {
|
|
/*
|
|
* nCycles is how many cycles we WANT to run on each iteration of stepCPU(), and may be as
|
|
* HIGH as nCyclesPerYield, but it may be significantly less. getBurstCycles() will adjust
|
|
* nCycles downward if any CPU timers need to fire during the next burst.
|
|
*/
|
|
var nCycles = this.getBurstCycles(this.flags.checksum? 1 : this.nCyclesPerYield);
|
|
|
|
/*
|
|
* Execute the burst.
|
|
*/
|
|
this.stepCPU(nCycles);
|
|
|
|
/*
|
|
* 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 first started).
|
|
*/
|
|
this.nCyclesThisRun += nCycles;
|
|
this.nRunCycles += nCycles;
|
|
this.updateChecksum(nCycles);
|
|
|
|
/*
|
|
* Update any/all timers, firing those whose cycle countdowns have reached (or dropped below) zero.
|
|
*/
|
|
this.updateTimers(nCycles);
|
|
|
|
this.nCyclesNextYield -= nCycles;
|
|
if (this.nCyclesNextYield <= 0) {
|
|
this.nCyclesNextYield += this.nCyclesPerYield;
|
|
if (++this.nYieldsSinceStatusUpdate >= CPU8080.YIELDS_PER_STATUS) {
|
|
if (this.cmp) this.cmp.updateStatus();
|
|
this.nYieldsSinceStatusUpdate = 0;
|
|
}
|
|
break;
|
|
}
|
|
} while (this.flags.running);
|
|
}
|
|
catch (e) {
|
|
this.stopCPU();
|
|
this.updateCPU();
|
|
if (this.cmp) this.cmp.stop(Component.getTime(), this.getCycles());
|
|
this.setBusy(false);
|
|
this.setError(e.stack || e.message);
|
|
return;
|
|
}
|
|
|
|
setTimeout(this.onRunTimeout, this.calcRemainingTime());
|
|
}
|
|
|
|
/**
|
|
* startCPU(fUpdateFocus)
|
|
*
|
|
* WARNING: Other components must use runCPU() to get the CPU running; this is a runCPU() helper function only.
|
|
*
|
|
* @param {boolean} [fUpdateFocus]
|
|
*/
|
|
startCPU(fUpdateFocus)
|
|
{
|
|
if (!this.flags.running) {
|
|
/*
|
|
* setSpeed() without a speed parameter leaves the selected speed in place, but also resets the
|
|
* cycle counter and timestamp for the current series of runCPU() calls, calculates the maximum number
|
|
* of cycles for each burst based on the last known effective CPU speed, and resets the nCyclesRecalc
|
|
* threshold counter.
|
|
*/
|
|
this.setSpeed();
|
|
if (this.cmp) this.cmp.start(this.msStartRun, this.getCycles());
|
|
this.flags.running = true;
|
|
this.flags.starting = true;
|
|
if (this.chipset) this.chipset.start();
|
|
var controlRun = this.bindings["run"];
|
|
if (controlRun) controlRun.textContent = "Halt";
|
|
if (this.cmp) {
|
|
this.cmp.updateStatus(true);
|
|
if (fUpdateFocus) this.cmp.updateFocus(true);
|
|
}
|
|
}
|
|
}
|
|
|
|
/**
|
|
* stepCPU(nMinCycles)
|
|
*
|
|
* This will be implemented by the CPUState8080 component.
|
|
*
|
|
* @this {CPU8080}
|
|
* @param {number} nMinCycles (0 implies a single-step, and therefore breakpoints should be ignored)
|
|
* @return {number} of cycles executed; 0 indicates that the last instruction was not executed
|
|
*/
|
|
stepCPU(nMinCycles)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* stopCPU(fComplete)
|
|
*
|
|
* For use by any component that wants to stop the CPU.
|
|
*
|
|
* This similar to yieldCPU(), but it doesn't need to zero nCyclesNextYield to break out of runCPU();
|
|
* it simply needs to clear fRunning (well, "simply" may be oversimplifying a bit....)
|
|
*
|
|
* @this {CPU8080}
|
|
* @param {boolean} [fComplete]
|
|
*/
|
|
stopCPU(fComplete)
|
|
{
|
|
this.isBusy(true);
|
|
this.endBurst();
|
|
this.addCycles(this.nRunCycles);
|
|
this.nRunCycles = 0;
|
|
if (this.flags.running) {
|
|
this.flags.running = false;
|
|
if (this.chipset) this.chipset.stop();
|
|
var controlRun = this.bindings["run"];
|
|
if (controlRun) controlRun.textContent = "Run";
|
|
}
|
|
this.flags.complete = fComplete;
|
|
}
|
|
|
|
/**
|
|
* updateCPU(fForce)
|
|
*
|
|
* This used to be performed at the end of every stepCPU(), but runCPU() -- which relies upon
|
|
* stepCPU() -- needed to have more control over when these updates are performed. However, for
|
|
* other callers of stepCPU(), such as the Debugger, the combination of stepCPU() + updateCPU()
|
|
* provides the old behavior.
|
|
*
|
|
* @this {CPU8080}
|
|
* @param {boolean} [fForce] (true to force a video update; used by the Debugger)
|
|
*/
|
|
updateCPU(fForce)
|
|
{
|
|
if (this.cmp) {
|
|
this.cmp.updateVideo(fForce);
|
|
this.cmp.updateStatus(fForce);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* yieldCPU()
|
|
*
|
|
* Similar to stopCPU() with regard to how it resets various cycle countdown values, but the CPU
|
|
* remains in a "running" state.
|
|
*
|
|
* @this {CPU8080}
|
|
*/
|
|
yieldCPU()
|
|
{
|
|
this.endBurst(); // this will break us out of stepCPU()
|
|
this.nCyclesNextYield = 0; // this will break us out of runCPU(), once we break out of stepCPU()
|
|
// if (DEBUG) this.nSnapCycles = this.nBurstCycles;
|
|
/*
|
|
* The Debugger calls yieldCPU() after every message() to ensure browser responsiveness, but it looks
|
|
* odd for those messages to show CPU state changes but for the CPU's own status display to not (ditto
|
|
* for the Video display), so I've added this call to try to keep things looking synchronized.
|
|
*/
|
|
this.updateCPU();
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Constants that control the frequency at which various updates should occur.
|
|
*
|
|
* These values do NOT control the simulation directly. Instead, they are used by
|
|
* calcCycles(), which uses the nCyclesPerSecond passed to the constructor as a starting
|
|
* point and computes the following variables:
|
|
*
|
|
* this.nCyclesPerYield: (this.nCyclesPerSecond / CPU8080.YIELDS_PER_SECOND)
|
|
*
|
|
* The above variables are also multiplied by any cycle multiplier in effect, via setSpeed(),
|
|
* and then they're used to initialize another set of variables for each runCPU() iteration:
|
|
*
|
|
* this.nCyclesNextYield: this.nCyclesPerYield
|
|
*/
|
|
CPU8080.YIELDS_PER_SECOND = 30; // just a gut feeling for the MINIMUM number of yields per second
|
|
CPU8080.YIELDS_PER_STATUS = 15; // every 15 yields (ie, twice per second), perform CPU status updates
|
|
|
|
CPU8080.BUTTONS = ["power", "reset"];
|
|
|
|
if (NODE) module.exports = CPU8080;
|