/*
* MIPS-Stimulator : logical-shift.js [Shift Logic 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: logicalShift
* @desc Performs logical SHIFT Operation Inside Virtual Machine
* @param {Object} item - Operand Details and Arguments
* @param {Number} i - Index of The Instrcution
*/
const logicalShift = function (item, i) {
const [ dest, src, imm ] = item.argument;
const valr = this.valueFromRegister(src, i);
const vali = Number(imm);
if (isNaN(vali)) {
console.error(`Type Error: Invalid value found at ${i}`);
process.exit(4);
}
switch (item.type) {
case "Left": {
this.loadOnRegister(dest, parseInt(valr << vali, 10), i);
break;
}
case "Right": {
this.loadOnRegister(dest, parseInt(valr >>> vali, 10), i);
break;
}
default:
console.error(`Error: Invalid ALU instrcution found at ${i}`);
process.exit(4);
}
};
module.exports = logicalShift;