137 lines
4.6 KiB
JavaScript
137 lines
4.6 KiB
JavaScript
"use strict";
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// Worker that manages a WebAssembly instance of the C core library
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(globalThis.Emulator = class Emulator {
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// Static initializer
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static initializer() {
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new Emulator();
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}
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// Object constructor
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constructor() {
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// Configure instance fields
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this.buffers = {};
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// Configure message port
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onmessage = e=>this.onmessage(e.data);
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}
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///////////////////////////// Message Methods /////////////////////////////
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// Message received
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onmessage(msg) {
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switch (msg.command) {
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case "GetRegisters": this.getRegisters(msg); break;
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case "Init" : this.init (msg); break;
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case "ReadBuffer" : this.readBuffer (msg); break;
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case "SetRegister" : this.setRegister (msg); break;
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case "SetROM" : this.setROM (msg); break;
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}
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}
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// Retrieve the values of all the CPU registers
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getRegisters(msg) {
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msg.pc = this.core.GetProgramCounter(msg.sim, 0);
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msg.pcFrom = this.core.GetProgramCounter(msg.sim, 1);
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msg.pcTo = this.core.GetProgramCounter(msg.sim, 2);
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msg.adtre = this.core.GetSystemRegister(msg.sim, 25);
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msg.chcw = this.core.GetSystemRegister(msg.sim, 24);
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msg.ecr = this.core.GetSystemRegister(msg.sim, 4);
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msg.eipc = this.core.GetSystemRegister(msg.sim, 0);
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msg.eipsw = this.core.GetSystemRegister(msg.sim, 1);
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msg.fepc = this.core.GetSystemRegister(msg.sim, 2);
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msg.fepsw = this.core.GetSystemRegister(msg.sim, 3);
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msg.pir = this.core.GetSystemRegister(msg.sim, 6);
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msg.psw = this.core.GetSystemRegister(msg.sim, 5);
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msg.tkcw = this.core.GetSystemRegister(msg.sim, 7);
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msg.sr29 = this.core.GetSystemRegister(msg.sim, 29);
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msg.sr30 = this.core.GetSystemRegister(msg.sim, 30);
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msg.sr31 = this.core.GetSystemRegister(msg.sim, 31);
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msg.program = new Array(32);
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for (let x = 0; x <= 31; x++)
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msg.program[x] = this.core.GetProgramRegister(msg.sim, x);
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postMessage(msg);
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}
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// Initialize the WebAssembly core module
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async init(msg) {
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// Load and instantiate the WebAssembly module
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this.wasm = await WebAssembly.instantiate(msg.wasm,
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{ env: { emscripten_notify_memory_growth: ()=>this.onmemory() }});
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this.wasm.instance.exports.Init();
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// Configure instance fields
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this.core = this.wasm.instance.exports;
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postMessage({ command: "Init" });
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}
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// Read multiple data units from the bus
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readBuffer(msg) {
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let buffer = this.malloc(Uint8Array, msg.size);
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this.core.ReadBuffer(msg.sim, buffer.pointer,
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msg.address, msg.size, msg.debug ? 1 : 0);
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msg.buffer = this.core.memory.buffer.slice(
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buffer.pointer, buffer.pointer + msg.size);
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this.free(buffer);
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postMessage(msg, msg.buffer);
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}
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// Specify a new value for a register
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setRegister(msg) {
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switch (msg.type) {
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case "pc" : msg.value =
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this.core.SetProgramCounter (msg.sim, msg.value);
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break;
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case "program": msg.value =
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this.core.SetProgramRegister(msg.sim, msg.id, msg.value);
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break;
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case "system" : msg.value =
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this.core.SetSystemRegister (msg.sim, msg.id, msg.value);
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}
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postMessage(msg);
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}
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// Supply a ROM buffer
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setROM(msg) {
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let rom = new Uint8Array(msg.rom);
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let buffer = this.malloc(Uint8Array, rom.length);
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for (let x = 0; x < rom.length; x++)
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buffer.data[x] = rom[x];
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msg.success = !!this.core.SetROM(msg.sim, buffer.pointer, rom.length);
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delete msg.rom;
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postMessage(msg);
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}
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///////////////////////////// Private Methods /////////////////////////////
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// Delete a previously-allocated memory buffer
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free(buffer) {
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this.core.Free(buffer.pointer);
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delete this.buffers[buffer.pointer];
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}
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// Allocate a typed array in WebAssembly core memory
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malloc(type, size) {
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let pointer = this.core.Malloc(size);
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let data = new type(this.core.memory.buffer, pointer, size);
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return this.buffers[pointer] = { data: data, pointer: pointer };
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}
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// WebAssembly memory has grown
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onmemory() {
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for (let buffer of Object.values(this.buffers)) {
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buffer.data = new buffer.data.constructor(
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this.core.memory.buffer, buffer.pointer);
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}
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}
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}).initializer();
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