About stdlib...
We believe in a future in which the web is a preferred environment for numerical computation. To help realize this future, we've built stdlib. stdlib is a standard library, with an emphasis on numerical and scientific computation, written in JavaScript (and C) for execution in browsers and in Node.js.
The library is fully decomposable, being architected in such a way that you can swap out and mix and match APIs and functionality to cater to your exact preferences and use cases.
When you use stdlib, you can be absolutely certain that you are using the most thorough, rigorous, wellwritten, studied, documented, tested, measured, and highquality code out there.
To join us in bringing numerical computing to the web, get started by checking us out on GitHub, and please consider financially supporting stdlib. We greatly appreciate your continued support!
Set High Word
Set the more significant 32 bits of a doubleprecision floatingpoint number.
Installation
npm install @stdlib/numberfloat64basesethighword
Usage
var setHighWord = require( '@stdlib/numberfloat64basesethighword' );
setHighWord( x, high )
Sets the more significant 32 bits (higher order word) of a doubleprecision floatingpoint number x
to a bit sequence represented by an unsigned 32bit integer high
. The returned double
will have the same less significant 32 bits (lower order word) as x
.
var high = 5 >>> 0; // => 0 00000000000 00000000000000000101
var y = setHighWord( 3.14e201, high ); // => 0 00000000000 0000000000000000010110010011110010110101100010000010
// returns 1.18350528745e313
var PINF = require( '@stdlib/constantsfloat64pinf' ); // => 0 11111111111 00000000000000000000 00000000000000000000000000000000
high = 1072693248 >>> 0; // => 0 01111111111 00000000000000000000
// Set the higher order bits of `+infinity` to return `1`:
y = setHighWord( PINF, high ); // => 0 01111111111 0000000000000000000000000000000000000000000000000000
// returns 1.0
Examples
var pow = require( '@stdlib/mathbasespecialpow' );
var round = require( '@stdlib/mathbasespecialround' );
var randu = require( '@stdlib/randombaserandu' );
var MAX_UINT32 = require( '@stdlib/constantsuint32max' );
var setHighWord = require( '@stdlib/numberfloat64basesethighword' );
var high;
var frac;
var exp;
var x;
var y;
var i;
// Generate a random doubleprecision floatingpoint number:
frac = randu() * 10.0;
exp = round( randu() * 323.0 );
x = frac * pow( 10.0, exp );
// Replace the higher order word of `x` to generate new random numbers having the same lower order word...
for ( i = 0; i < 100; i++ ) {
high = round( randu()*MAX_UINT32 );
y = setHighWord( x, high );
console.log( 'x: %d. new high word: %d. y: %d.', x, high, y );
}
C APIs
Usage
#include "stdlib/number/float64/base/set_high_word.h"
stdlib_base_float64_set_high_word( high, *x )
Sets the more significant 32 bits of a doubleprecision floatingpoint number.
#include <stdint.h>
uint32_t high = 1074339512;
double x = 0.0;
stdlib_base_float64_set_high_word( high, &x );
The function accepts the following arguments:

high:
[in] uint32_t
higher order word. 
x:
[inout] double*
reference to (and destination for) a doubleprecision floatingpoint number.
void stdlib_base_float64_set_high_word( const uint32_t high, double *x );
Examples
#include "stdlib/number/float64/base/set_high_word.h"
#include <stdint.h>
#include <stdio.h>
int main( void ) {
uint32_t high[] = { 1074339512, 1074339513, 1074339514, 1074339515 };
double x = 3.14;
int i;
for ( i = 0; i < 4; i++ ) {
stdlib_base_float64_set_high_word( high[ i ], &x );
printf( "high: %u => %lf\n", high[ i ], x );
}
}
See Also

@stdlib/numberfloat64/base/gethighword
: return an unsigned 32bit integer corresponding to the more significant 32 bits of a doubleprecision floatingpoint number. 
@stdlib/numberfloat64/base/setlowword
: set the less significant 32 bits of a doubleprecision floatingpoint number.
Notice
This package is part of stdlib, a standard library for JavaScript and Node.js, with an emphasis on numerical and scientific computing. The library provides a collection of robust, high performance libraries for mathematics, statistics, streams, utilities, and more.
For more information on the project, filing bug reports and feature requests, and guidance on how to develop stdlib, see the main project repository.
Community
License
See LICENSE.
Copyright
Copyright © 20162024. The Stdlib Authors.