time-to-botec

Benchmark sampling in different programming languages
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main.js (1839B)

      1 /**
      2 * @license Apache-2.0
      3 *
      4 * Copyright (c) 2018 The Stdlib Authors.
      5 *
      6 * Licensed under the Apache License, Version 2.0 (the "License");
      7 * you may not use this file except in compliance with the License.
      8 * You may obtain a copy of the License at
      9 *
     10 *    http://www.apache.org/licenses/LICENSE-2.0
     11 *
     12 * Unless required by applicable law or agreed to in writing, software
     13 * distributed under the License is distributed on an "AS IS" BASIS,
     14 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     15 * See the License for the specific language governing permissions and
     16 * limitations under the License.
     17 */
     18 
     19 'use strict';
     20 
     21 // MODULES //
     22 
     23 var toUint32 = require( './../../../../int32/base/to-uint32' );
     24 
     25 
     26 // VARIABLES //
     27 
     28 // Shift mask: 00000000000000000000000000011111
     29 var MAX_SHIFT = toUint32( 31 );
     30 
     31 
     32 // MAIN //
     33 
     34 /**
     35 * Performs a bitwise rotation to the right.
     36 *
     37 * ## References
     38 *
     39 * -   [Safe, Efficient, and Portable Rotate in C/C++](http://blog.regehr.org/archives/1063)
     40 * -   [Best practices for rotates in C/C++](https://stackoverflow.com/a/776523/224132)
     41 * -   [Near constant time rotate that does not violate the standards](https://stackoverflow.com/a/31488147/224132)
     42 *
     43 *
     44 * @param {uinteger32} x - unsigned integer
     45 * @param {uinteger32} shift - number of bits to shift
     46 * @returns {uinteger32} shifted integer
     47 *
     48 * @example
     49 * var toBinaryStringUint32 = require( '@stdlib/number/uint32/base/to-binary-string' );
     50 *
     51 * var bstr = toBinaryStringUint32( 2147483649 );
     52 * // returns '10000000000000000000000000000001'
     53 *
     54 * var x = rotr32( 2147483649, 10 );
     55 * // returns 6291456
     56 *
     57 * bstr = toBinaryStringUint32( x );
     58 * // returns '00000000011000000000000000000000'
     59 */
     60 function rotr32( x, shift ) {
     61 	shift &= MAX_SHIFT;
     62 	return toUint32( ( x >>> shift ) | (x << ((-shift) & MAX_SHIFT)) );
     63 }
     64 
     65 
     66 // EXPORTS //
     67 
     68 module.exports = rotr32;