hdl-js/dist/emulator/hardware/builtin-gates/ALU.js

Hardware definition language (HDL) and Hardware simulator

/**
 * The MIT License (MIT)
 * Copyright (c) 2017-present Dmitry Soshnikov <dmitry.soshnikov@gmail.com>
 */

'use strict';

var _createClass = function () { function defineProperties(target, props) { for (var i = 0; i < props.length; i++) { var descriptor = props[i]; descriptor.enumerable = descriptor.enumerable || false; descriptor.configurable = true; if ("value" in descriptor) descriptor.writable = true; Object.defineProperty(target, descriptor.key, descriptor); } } return function (Constructor, protoProps, staticProps) { if (protoProps) defineProperties(Constructor.prototype, protoProps); if (staticProps) defineProperties(Constructor, staticProps); return Constructor; }; }();

function _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } }

function _possibleConstructorReturn(self, call) { if (!self) { throw new ReferenceError("this hasn't been initialised - super() hasn't been called"); } return call && (typeof call === "object" || typeof call === "function") ? call : self; }

function _inherits(subClass, superClass) { if (typeof superClass !== "function" && superClass !== null) { throw new TypeError("Super expression must either be null or a function, not " + typeof superClass); } subClass.prototype = Object.create(superClass && superClass.prototype, { constructor: { value: subClass, enumerable: false, writable: true, configurable: true } }); if (superClass) Object.setPrototypeOf ? Object.setPrototypeOf(subClass, superClass) : subClass.__proto__ = superClass; }

var BuiltInGate = require('../BuiltInGate');

var _require = require('../../../util/numbers'),
    int16Table = _require.int16Table,
    int16 = _require.int16;

/**
 * Canonical truth table for the `ALU` gate.
 */
// prettier-ignore


var TRUTH_TABLE = int16Table([{ x: 0, y: 65535, zx: 1, nx: 0, zy: 1, ny: 0, f: 1, no: 0, out: 0, zr: 1, ng: 0 }, { x: 0, y: 65535, zx: 1, nx: 1, zy: 1, ny: 1, f: 1, no: 1, out: 1, zr: 0, ng: 0 }, { x: 0, y: 65535, zx: 1, nx: 1, zy: 1, ny: 0, f: 1, no: 0, out: 65535, zr: 0, ng: 1 }, { x: 0, y: 65535, zx: 0, nx: 0, zy: 1, ny: 1, f: 0, no: 0, out: 0, zr: 1, ng: 0 }, { x: 0, y: 65535, zx: 1, nx: 1, zy: 0, ny: 0, f: 0, no: 0, out: 65535, zr: 0, ng: 1 }, { x: 0, y: 65535, zx: 0, nx: 0, zy: 1, ny: 1, f: 0, no: 1, out: 65535, zr: 0, ng: 1 }, { x: 0, y: 65535, zx: 1, nx: 1, zy: 0, ny: 0, f: 0, no: 1, out: 0, zr: 1, ng: 0 }, { x: 0, y: 65535, zx: 0, nx: 0, zy: 1, ny: 1, f: 1, no: 1, out: 0, zr: 1, ng: 0 }, { x: 0, y: 65535, zx: 1, nx: 1, zy: 0, ny: 0, f: 1, no: 1, out: 1, zr: 0, ng: 0 }, { x: 0, y: 65535, zx: 0, nx: 1, zy: 1, ny: 1, f: 1, no: 1, out: 1, zr: 0, ng: 0 }, { x: 0, y: 65535, zx: 1, nx: 1, zy: 0, ny: 1, f: 1, no: 1, out: 0, zr: 1, ng: 0 }, { x: 0, y: 65535, zx: 0, nx: 0, zy: 1, ny: 1, f: 1, no: 0, out: 65535, zr: 0, ng: 1 }, { x: 0, y: 65535, zx: 1, nx: 1, zy: 0, ny: 0, f: 1, no: 0, out: 65534, zr: 0, ng: 1 }, { x: 0, y: 65535, zx: 0, nx: 0, zy: 0, ny: 0, f: 1, no: 0, out: 65535, zr: 0, ng: 1 }, { x: 0, y: 65535, zx: 0, nx: 1, zy: 0, ny: 0, f: 1, no: 1, out: 1, zr: 0, ng: 0 }, { x: 0, y: 65535, zx: 0, nx: 0, zy: 0, ny: 1, f: 1, no: 1, out: 65535, zr: 0, ng: 1 }, { x: 0, y: 65535, zx: 0, nx: 0, zy: 0, ny: 0, f: 0, no: 0, out: 0, zr: 1, ng: 0 }, { x: 0, y: 65535, zx: 0, nx: 1, zy: 0, ny: 1, f: 0, no: 1, out: 65535, zr: 0, ng: 1 }, { x: 17, y: 3, zx: 1, nx: 0, zy: 1, ny: 0, f: 1, no: 0, out: 0, zr: 1, ng: 0 }, { x: 17, y: 3, zx: 1, nx: 1, zy: 1, ny: 1, f: 1, no: 1, out: 1, zr: 0, ng: 0 }, { x: 17, y: 3, zx: 1, nx: 1, zy: 1, ny: 0, f: 1, no: 0, out: 65535, zr: 0, ng: 1 }, { x: 17, y: 3, zx: 0, nx: 0, zy: 1, ny: 1, f: 0, no: 0, out: 17, zr: 0, ng: 0 }, { x: 17, y: 3, zx: 1, nx: 1, zy: 0, ny: 0, f: 0, no: 0, out: 3, zr: 0, ng: 0 }, { x: 17, y: 3, zx: 0, nx: 0, zy: 1, ny: 1, f: 0, no: 1, out: 65518, zr: 0, ng: 1 }, { x: 17, y: 3, zx: 1, nx: 1, zy: 0, ny: 0, f: 0, no: 1, out: 65532, zr: 0, ng: 1 }, { x: 17, y: 3, zx: 0, nx: 0, zy: 1, ny: 1, f: 1, no: 1, out: 65519, zr: 0, ng: 1 }, { x: 17, y: 3, zx: 1, nx: 1, zy: 0, ny: 0, f: 1, no: 1, out: 65533, zr: 0, ng: 1 }, { x: 17, y: 3, zx: 0, nx: 1, zy: 1, ny: 1, f: 1, no: 1, out: 18, zr: 0, ng: 0 }, { x: 17, y: 3, zx: 1, nx: 1, zy: 0, ny: 1, f: 1, no: 1, out: 4, zr: 0, ng: 0 }, { x: 17, y: 3, zx: 0, nx: 0, zy: 1, ny: 1, f: 1, no: 0, out: 16, zr: 0, ng: 0 }, { x: 17, y: 3, zx: 1, nx: 1, zy: 0, ny: 0, f: 1, no: 0, out: 2, zr: 0, ng: 0 }, { x: 17, y: 3, zx: 0, nx: 0, zy: 0, ny: 0, f: 1, no: 0, out: 20, zr: 0, ng: 0 }, { x: 17, y: 3, zx: 0, nx: 1, zy: 0, ny: 0, f: 1, no: 1, out: 14, zr: 0, ng: 0 }, { x: 17, y: 3, zx: 0, nx: 0, zy: 0, ny: 1, f: 1, no: 1, out: 65522, zr: 0, ng: 1 }, { x: 17, y: 3, zx: 0, nx: 0, zy: 0, ny: 0, f: 0, no: 0, out: 1, zr: 0, ng: 0 }, { x: 17, y: 3, zx: 0, nx: 1, zy: 0, ny: 1, f: 0, no: 1, out: 19, zr: 0, ng: 0 }]);

/**
 * The ALU (Arithmetic Logic Unit).
 *
 * Computes one of the following functions:
 *
 * x+y, x-y, y-x, 0, 1, -1, x, y, -x, -y, !x, !y,
 * x+1, y+1, x-1, y-1, x&y, x|y on two 16-bit inputs,
 * according to 6 input bits denoted zx, nx, zy, ny, f, no.
 *
 * In addition, the ALU computes two 1-bit outputs:
 *
 * if the ALU output == 0, zr is set to 1; otherwise zr is set to 0;
 * if the ALU output < 0, ng is set to 1; otherwise ng is set to 0.
 *
 * Implementation: the ALU logic manipulates the x and y inputs
 * and operates on the resulting values, as follows:
 *
 * if (zx === 1) set x = 0        // 16-bit constant
 * if (nx === 1) set x = ~x       // bitwise not
 * if (zy === 1) set y = 0        // 16-bit constant
 * if (ny === 1) set y = ~y       // bitwise not
 * if (f === 1)  set out = x + y  // integer 2's complement addition
 * if (f === 0)  set out = x & y  // bitwise and
 * if (no === 1) set out = !out   // bitwise not
 * if (out === 0) set zr = 1
 * if (out < 0) set ng = 1
 */

var ALU = function (_BuiltInGate) {
  _inherits(ALU, _BuiltInGate);

  function ALU() {
    _classCallCheck(this, ALU);

    return _possibleConstructorReturn(this, (ALU.__proto__ || Object.getPrototypeOf(ALU)).apply(this, arguments));
  }

  _createClass(ALU, [{
    key: 'eval',

    /**
     * Evaluates ALU logic.
     */
    value: function _eval() {
      var x = this.getInputPins()[0].getValue();
      var y = this.getInputPins()[1].getValue();

      var zx = this.getInputPins()[2].getValue();
      var nx = this.getInputPins()[3].getValue();
      var zy = this.getInputPins()[4].getValue();
      var ny = this.getInputPins()[5].getValue();
      var f = this.getInputPins()[6].getValue();
      var no = this.getInputPins()[7].getValue();

      var out = void 0;

      if (zx === 1) {
        x = 0;
      }

      if (zy === 1) {
        y = 0;
      }

      if (nx === 1) {
        x = int16(~x);
      }

      if (ny === 1) {
        y = int16(~y);
      }

      if (f === 1) {
        out = int16(x + y);
      } else if (f === 0) {
        out = int16(x & y);
      }

      if (no === 1) {
        out = int16(~out);
      }

      this.getOutputPins()[0].setValue(out); // main out
      this.getOutputPins()[1].setValue(out === 0 ? 1 : 0); // zr
      this.getOutputPins()[2].setValue(out < 0 ? 1 : 0); // ng
    }
  }]);

  return ALU;
}(BuiltInGate);

/**
 * Specification of the `ALU` gate.
 */


ALU.Spec = {
  name: 'ALU',

  description: 'The ALU (Arithmetic Logic Unit).\n\nComputes one of the following functions:\n\nx+y, x-y, y-x, 0, 1, -1, x, y, -x, -y, !x, !y,\nx+1, y+1, x-1, y-1, x&y, x|y on two 16-bit inputs,\naccording to 6 input bits denoted zx, nx, zy, ny, f, no.\n\nIn addition, the ALU computes two 1-bit outputs:\n\nif the ALU output == 0, zr is set to 1; otherwise zr is set to 0;\nif the ALU output < 0, ng is set to 1; otherwise ng is set to 0.\n',

  inputPins: [
  // Main inputs.
  { name: 'x', size: 16 }, { name: 'y', size: 16 },

  // Should zero `x`?
  { name: 'zx', size: 1 },

  // Should negate `x`?
  { name: 'nx', size: 1 },

  // Should zero `y`?
  { name: 'zy', size: 1 },

  // Should negate `y`?
  { name: 'ny', size: 1 },

  // Opcode: 1 - And, 0 - Add.
  { name: 'f', size: 1 },

  // Should negate `out`?
  { name: 'no', size: 1 }],

  outputPins: [{ name: 'out', size: 16 },

  // Is result zero?
  { name: 'zr', size: 1 },

  // Is result negative?
  { name: 'ng', size: 1 }],

  truthTable: TRUTH_TABLE
};

module.exports = ALU;