hdl-js/dist/util/numbers.js

Hardware definition language (HDL) and Hardware simulator

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

'use strict';

/**
 * Converts a number to signed 16-bit integer.
 */

function int16(v) {
  if (typeof v === 'string') {
    v = Number.parseInt(v, 2);
  }

  return v << 16 >> 16;
}

/**
 * Converts all rows in a table to `int16`.
 */
function int16Table(table) {
  var _iteratorNormalCompletion = true;
  var _didIteratorError = false;
  var _iteratorError = undefined;

  try {
    for (var _iterator = table[Symbol.iterator](), _step; !(_iteratorNormalCompletion = (_step = _iterator.next()).done); _iteratorNormalCompletion = true) {
      var row = _step.value;

      for (var pin in row) {
        if (pin === '$clock') {
          continue;
        }
        row[pin] = int16(row[pin]);
      }
    }
  } catch (err) {
    _didIteratorError = true;
    _iteratorError = err;
  } finally {
    try {
      if (!_iteratorNormalCompletion && _iterator.return) {
        _iterator.return();
      }
    } finally {
      if (_didIteratorError) {
        throw _iteratorError;
      }
    }
  }

  return table;
}

/**
 * Converts a number to unsigned 16-bit integer.
 */
function uint16(v) {
  return v & 0xffff;
}

/**
 * Test for a neagtive zero.
 */
function isNegativeZero(value) {
  return value === 0 && 1 / value === -Infinity;
}

/**
 * Converts a number value to decimal string with the sign.
 */
function toSignedString(value) {
  if (isNegativeZero(value)) {
    return '-0';
  }

  return (value >= 0 ? '+' : '') + value;
}

/**
 * Returns the value of particular bit in a 16-bit number.
 */
function getBitAt(number, index) {
  return number >> index & 1;
}

/**
 * Sets a particular bit to the value.
 */
function setBitAt(number, index, value) {
  // Set 1.
  if (value === 1) {
    number |= 1 << index;
  } else {
    // Set 0 ("clear").
    number &= ~(1 << index);
  }
  return number;
}

/**
 * Returns a bit range.
 */
function getBitRange(number, from, to) {
  return number >> from & (1 << to + 1 - from) - 1;
}

/**
 * Sets a bits range.
 */
function setBitRange(number, from, to, range) {
  var mask = (1 << to + 1 - from) - 1 << from;
  return number & ~mask | range << from & mask;
}

module.exports = {
  getBitAt: getBitAt,
  getBitRange: getBitRange,
  int16: int16,
  int16Table: int16Table,
  isNegativeZero: isNegativeZero,
  setBitAt: setBitAt,
  setBitRange: setBitRange,
  toSignedString: toSignedString,
  uint16: uint16
};