/*
* MIPS-Stimulator : load.js [Load submodule for VM]
* Copyright (C) 2017 Progyan Bhattacharya, Bytes Club
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
"use strict";
/** function: load
* @desc Performs Load Operation Inside Virtual Machine
* @param {Object} item - Operand Details and Arguments
* @param {Number} i - Index of The Instrcution
*/
const load = function (item, i) {
switch (item.type) {
case "Integer": {
const [ dest, integer ] = item.argument;
this.loadOnRegister(dest, Number(integer), i);
break;
}
case "Address": {
const [ dest, label ] = item.argument;
const value = this.valueFromLabel(label, i);
this.loadOnRegister(dest, value, i);
break;
}
case "Register": {
const [ dest, src, ofs ] = item.argument;
const offset = typeof ofs !== "undefined" ?
Number(ofs) :
0;
const addr = Number(this.valueFromRegister(src, i));
const target = offset !== 0 ?
addr + Number(offset) :
addr;
const value = this.valueFromLabel(target, i);
this.loadOnRegister(dest, value, i);
break;
}
default:
console.error(`Error: Invalid load statement found at ${i}`);
process.exit(4);
}
};
module.exports = load;