105 lines
3.2 KiB
JavaScript
105 lines
3.2 KiB
JavaScript
|
/**
|
||
|
* Copyright 2020 wixette@gmail.com
|
||
|
*
|
||
|
* Licensed under the Apache License, Version 2.0 (the "License");
|
||
|
* you may not use this file except in compliance with the License.
|
||
|
* You may obtain a copy of the License at
|
||
|
*
|
||
|
* http://www.apache.org/licenses/LICENSE-2.0
|
||
|
*
|
||
|
* Unless required by applicable law or agreed to in writing, software
|
||
|
* distributed under the License is distributed on an "AS IS" BASIS,
|
||
|
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
||
|
* See the License for the specific language governing permissions and
|
||
|
* limitations under the License.
|
||
|
*
|
||
|
* @fileoverview Altair 8800 front panel simulator.
|
||
|
*/
|
||
|
|
||
|
|
||
|
/**
|
||
|
* The simulator.
|
||
|
*/
|
||
|
class Sim8800 {
|
||
|
/**
|
||
|
* @param {number} memSize The memory size, in bytes.
|
||
|
* @param {number} clockRate The clock rate.
|
||
|
*/
|
||
|
constructor(memSize, clockRate) {
|
||
|
/** @type {number} */
|
||
|
this.clockRate = clockRate;
|
||
|
/** @type {Array<number>} */
|
||
|
this.mem = new Array(memSize);
|
||
|
this.initMem();
|
||
|
}
|
||
|
|
||
|
/**
|
||
|
* Returns the byteTo (write memory) callback.
|
||
|
* @return {function(number, number)}
|
||
|
*/
|
||
|
getWriteByteCallback() {
|
||
|
var self = this;
|
||
|
return function(address, value) {
|
||
|
address = address % self.mem.length;
|
||
|
self.mem[address] = value;
|
||
|
window.console.log('writing byte @' + Sim8800.toHex(address, 8)
|
||
|
+ ' : ' + Sim8800.toHex(value, 2));
|
||
|
};
|
||
|
}
|
||
|
|
||
|
/**
|
||
|
* Returns the byteAt (read memory) callback.
|
||
|
* @return {function(number): number}
|
||
|
*/
|
||
|
getReadByteCallback() {
|
||
|
var self = this;
|
||
|
return function(address) {
|
||
|
address = address % self.mem.length;
|
||
|
var value = self.mem[address];
|
||
|
window.console.log('reading byte @' + Sim8800.toHex(address, 8)
|
||
|
+ ' : ' + Sim8800.toHex(value, 2));
|
||
|
return value;
|
||
|
};
|
||
|
}
|
||
|
|
||
|
/**
|
||
|
* Formats a number to fixed length hex string.
|
||
|
* @param {number} n The number to be formatted.
|
||
|
* @param {number} len The output length, with leading zeros.
|
||
|
*/
|
||
|
static toHex(n, len) {
|
||
|
var leadingZeros = (new Array(len)).fill('0').join('');
|
||
|
return (leadingZeros + n.toString(16)).substr(-len);
|
||
|
}
|
||
|
|
||
|
/**
|
||
|
* Fills the memory with random numbers.
|
||
|
*/
|
||
|
initMem() {
|
||
|
for (let i = 0; i < this.mem.length; i++) {
|
||
|
this.mem[i] = Math.floor(Math.random() * 256);
|
||
|
}
|
||
|
}
|
||
|
|
||
|
/**
|
||
|
* Dumps the memory to HTML, for debugging or monitoring.
|
||
|
* @param {Element} containerElem The DOM element to hold the generated HTML.
|
||
|
*/
|
||
|
dumpMem(containerElem) {
|
||
|
var sb = ['<pre>\n'];
|
||
|
for (let i = 0; i < this.mem.length; i += 16) {
|
||
|
sb.push(Sim8800.toHex(i, 4));
|
||
|
sb.push(' ');
|
||
|
for (let j = i;
|
||
|
j < Math.min(this.mem.length, i + 16);
|
||
|
j++) {
|
||
|
sb.push(Sim8800.toHex(this.mem[j], 2));
|
||
|
sb.push((j + 1) % 8 == 0 ? ' ' : ' ');
|
||
|
}
|
||
|
sb.push('\n');
|
||
|
}
|
||
|
sb.push('</pre>\n');
|
||
|
containerElem.innerHTML = sb.join('');
|
||
|
}
|
||
|
};
|