cpu - WIP - Continue removing material that has to move elsewhere so that this can be treated as a library
This commit is contained in:
n loewen
parent
b173d46cb6
commit
b7d13087e6
201
src/cpu.js
201
src/cpu.js
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@ -3,7 +3,7 @@ const readlineSync = require('readline-sync');
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const {
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INITIAL_IP_ADDRESS,
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DEFAULT_CYCLE_LIMIT,
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DEFAULT_CYCLE_LIMIT: CYCLE_LIMIT,
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KEYPAD_ADDR,
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KEY_MAP,
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} = require('./machine.config');
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@ -29,6 +29,7 @@ const CPU = {
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/** Debug info **/
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debug: {
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sourceInfo: null,
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previousIP: 0,
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currentInstruction: {
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opcode: null,
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@ -40,12 +41,17 @@ const CPU = {
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/** Functions that update state **/
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/** @param {Uint8Array} data */
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/** @param {Uint8Array} data **/
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loadMemory(data) {
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this.state.memory = new Uint8Array(256);
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this.state.memory.set(data, 0);
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},
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/** @param {Array} info **/ // TODO type info
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loadSourceInfo(info) {
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this.debug.sourceInfo = info;
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},
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incrementIP(offset) {
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this.state.previousIP = this.state.IP;
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this.state.IP = this.state.IP + offset;
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@ -59,13 +65,52 @@ const CPU = {
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updateFlagZero() { this.state.flags.Z = this.state.acc === 0; },
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updateFlagNegative() { this.state.acc & 128 ? this.state.flags.N = true : this.state.flags.N = false },
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/**
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* Load code into memory and set CPU state to "state.running"
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* @param {Uint8Array} code - Machine code to load
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**/
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startCPU(code) {
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CPU.loadMemory(code);
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CPU.state.running = true;
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},
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/** Execute the next instruction in memory **/
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stepCPU() {
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CPU.cycleStartCallbacks.forEach((fn) => fn());
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if (CPU.state.IP >= CPU.state.memory.length) {
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console.error('HALTING - IP greater than memory size'); // TODO -- should this throw an error instead?
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CPU.state.running = false;
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} else {
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CPU.debug.currentInstruction.opcode = CPU.state.memory[CPU.state.IP];
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CPU.debug.currentInstruction.operand = CPU.state.memory[CPU.state.IP+1];
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let executeInstruction = opcodes2mnemonics[CPU.debug.currentInstruction.opcode];
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if (typeof executeInstruction === 'undefined') { failInvalidOpcode(); }
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executeInstruction(CPU.debug.currentInstruction.operand);
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CPU.debug.cycleCounter += 1;
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}
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// Temporary limit as a lazy way to halt infinite loops
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if ((CYCLE_LIMIT > 0) && CPU.debug.cycleCounter >= CYCLE_LIMIT) {
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console.warn(' HALTING - reached cycle limit'); // TODO -- throw error?
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CPU.state.running = false;
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}
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if (!CPU.state.running) process.exit();
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CPU.cycleEndCallbacks.forEach((fn) => fn());
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},
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/** Hooks **/
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onTickHooks: [],
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cycleStartCallbacks: [],
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cycleEndCallbacks: [],
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/** @param {function} fn **/
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onTick(fn) { this.onTickHooks.push(fn) },
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onCycleStart(fn) { this.cycleStartCallbacks.push(fn) },
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onCycleEnd(fn) { this.cycleEndCallbacks.push(fn) },
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}
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@ -296,144 +341,12 @@ const opcodes2mnemonics = {
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15: (operand) => Instructions.no_op(),
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};
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/**
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* Load code into memory and set CPU state to "state.running"
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* @param {Uint8Array} code - Machine code to load
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**/
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function startCPU(code) {
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CPU.loadMemory(code);
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CPU.debug.cycleCounter = 0;
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CPU.state.running = true;
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// FIXME: This conflicts with single-stepping
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// (you can single-step, but keys aren't passed
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// through to the Cardiograph)
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//
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// -> The fix is maybe to remove readlineSync,
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// and instead stash the keypress into a buffer variable.*
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// Then have the stepping function check that buffer,
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// and then clear the buffer, each time it runs.
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//
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// * If it's in the set of keys that are relevant
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// to single-stepping.
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// Start listening for keypresses...
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readline.emitKeypressEvents(process.stdin);
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if (process.stdin.setRawMode != null) {
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process.stdin.setRawMode(true);
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}
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process.stdin.on('keypress', (str, key) => { // TODO: is it possible to turn this off again?
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if (key.sequence === '\x03') process.exit();
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let name = key.name.toUpperCase();
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if (name in KEY_MAP) {
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CPU.state.memory[KEYPAD_ADDR] = KEY_MAP[name];
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}
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});
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}
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/**
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* Execute just the next instruction in memory
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* @param {Object} debugInfo
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* @param {Boolean} [debug] - Print machine status and the line of code being executed
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**/
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async function stepCPU(debugInfo, debug = false, prettyPrintDisplay = false) {
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if (CPU.state.IP >= CPU.state.memory.length) {
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console.error('HALTING - IP greater than memory size');
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CPU.state.running = false;
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process.exit();
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} else {
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CPU.debug.currentInstruction.opcode = CPU.state.memory[CPU.state.IP];
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CPU.debug.currentInstruction.operand = CPU.state.memory[CPU.state.IP+1];
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let executeInstruction = opcodes2mnemonics[CPU.debug.currentInstruction.opcode];
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if (typeof executeInstruction === 'undefined') {
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let info = debugInfo[CPU.previousIP];
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console.error();
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console.error(`Error: Invalid opcode`);
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console.error(` Executing $${num2hex(info.machine[0])} $${num2hex(info.machine[1])}`);
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console.error(` from line ${info.lineNumber}: ${info.source}`);
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process.exit();
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}
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executeInstruction(CPU.debug.currentInstruction.operand);
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CPU.debug.cycleCounter += 1;
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}
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logCPUState(debugInfo, debug, prettyPrintDisplay);
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if (DEFAULT_CYCLE_LIMIT) { // Temporary limit as a lazy way to halt infinite loops
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if (CPU.debug.cycleCounter >= DEFAULT_CYCLE_LIMIT) {
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console.warn(' HALTING - reached cycle limit');
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CPU.state.running = false;
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}
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}
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if (!CPU.state.running) process.exit();
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}
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/**
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* @param {Uint8Array} code - Machine code to run
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* @param {Object} debugInfo TODO type
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* @param {Boolean} [debug] - Enable/disable debugging printouts
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* @param {Boolean} [singleStep]
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* @param {Boolean} [prettyPrint] - Print display with black and white emoji, instead of in hex
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* @param {Number} [clockSpeed] - CPU clock speed in milliseconds
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**/
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exports.runProgram =
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(code, debugInfo, debug=false, singleStep=false, prettyPrint=false, clockSpeed=100) => {
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if (singleStep) {
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this.singleStepProgram(code, debugInfo, debug, prettyPrint);
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} else {
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startCPU(code);
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// Animate the output by pausing between steps
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const loop = setInterval(async () => {
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stepCPU(debugInfo, debug, prettyPrint);
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if (!CPU.state.running) {
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logCPUState(debugInfo, debug, prettyPrint);
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console.log('Halted');
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process.exit();
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}
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}, clockSpeed);
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}
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};
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/**
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* @param {Uint8Array} code - Machine code to run
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* @param {any} debugInfo - TODO
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* @param {Boolean} [debug] - Enable/disable debugging printouts
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* @param {Boolean} [prettyPrintDisplay] - Print display using black and white emoji
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**/
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exports.singleStepProgram = (code, debugInfo, debug = false, prettyPrintDisplay = false) => {
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startCPU(code);
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while (CPU.state.running) {
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stepCPU(debugInfo, debug, prettyPrintDisplay);
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// FIXME: this prevents exiting with Ctrl+C:
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let key = readlineSync.keyIn('S to step, Q to quit > ', {
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limit: ['s', 'S', 'q', 'Q'],
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});
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if (key.toLowerCase() === 'q') { process.exit(); }
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console.log();
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}
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}
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// FUNCTIONS THAT PULL INFO FROM STATE TO DISPLAY
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/**
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* @param {Boolean} [debug] - Enable/disable debugging printouts
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**/
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function logCPUState(debugInfo, debug = false, prettyPrintDisplay = false) {
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debugInfo = debugInfo[CPU.previousIP] !== 'undefined' ? debugInfo[CPU.previousIP] : false;
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console.group(`Step ${CPU.debug.cycleCounter}`);
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console.log();
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if (!debug) console.clear();
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display.show(CPU.state.memory, prettyPrintDisplay);
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console.log();
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if (debugInfo) {
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console.log(`Line ${debugInfo.lineNumber}: ${debugInfo.source}`);
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console.log();
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}
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console.log('Mnemonic:', CPU.debug.currentInstruction.mnemonic);
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console.log(`Machine: $${num2hex(CPU.debug.currentInstruction.opcode)} $${num2hex(CPU.debug.currentInstruction.operand)}`);
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console.log();
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console.log(`IP: $${num2hex(CPU.state.IP)} Acc: $${num2hex(CPU.state.acc)} ONZC ${bool2bit(CPU.state.flags.O)}${bool2bit(CPU.state.flags.N)}${bool2bit(CPU.state.flags.Z)}${bool2bit(CPU.state.flags.C)}`);
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console.log(`KEY: $${num2hex(CPU.state.memory[KEYPAD_ADDR])} ${CPU.state.running ? "state.running" : "halted" }`);
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console.log();
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console.log();
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console.groupEnd();
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};
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function failInvalidOpcode() {
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let info = CPU.debug.sourceInfo[CPU.previousIP];
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console.error();
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console.error(`Error: Invalid opcode`);
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console.error(` Executing $${num2hex(info.machine[0])} $${num2hex(info.machine[1])}`);
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console.error(` from line ${info.lineNumber}: ${info.source}`);
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process.exit();
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}
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