main.js (1720B)
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 toWord = require( './../../../../float32/base/to-word' ); 24 25 26 // MAIN // 27 28 /** 29 * Returns a boolean indicating if the sign bit is on (true) or off (false). 30 * 31 * @param {number} x - single-precision floating-point number 32 * @returns {boolean} boolean indicating if sign bit is on or off 33 * 34 * @example 35 * var toFloat32 = require( '@stdlib/number/float64/base/to-float32' ); 36 * var bool = signbitf( toFloat32( 4.0 ) ); 37 * // returns false 38 * 39 * @example 40 * var toFloat32 = require( '@stdlib/number/float64/base/to-float32' ); 41 * var bool = signbitf( toFloat32( -9.14e-34 ) ); 42 * // returns true 43 * 44 * @example 45 * var bool = signbitf( 0.0 ); 46 * // returns false 47 * 48 * @example 49 * var bool = signbitf( -0.0 ); 50 * // returns true 51 */ 52 function signbitf( x ) { 53 // Convert `x` to an unsigned 32-bit integer corresponding to the value's IEEE 754 binary representation: 54 var w = toWord( x ); 55 56 // Shift off all bits which are not the sign bit and check if the sign bit is on: 57 return ( w >>> 31 ) ? true : false; // eslint-disable-line no-unneeded-ternary 58 } 59 60 61 // EXPORTS // 62 63 module.exports = signbitf;