Split a double-precision floating-point number into a higher order word and a lower order word.
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> Split a [double-precision floating-point number][ieee754] into a higher order word and a lower order word.
``bash`
npm install @stdlib/number-float64-base-to-words
`javascript`
var toWords = require( '@stdlib/number-float64-base-to-words' );
#### toWords( x )
Splits a [double-precision floating-point number][ieee754] into a higher order word (unsigned 32-bit integer) and a lower order word (unsigned 32-bit integer).
`javascript`
var w = toWords( 3.14e201 );
// returns [ 1774486211, 2479577218 ]
By default, the function returns an array containing two elements: a higher order word and a lower order word. The lower order word contains the less significant bits, while the higher order word contains the more significant bits and includes the exponent and sign.
`javascript
var w = toWords( 3.14e201 );
// returns [ 1774486211, 2479577218 ]
var high = w[ 0 ];
// returns 1774486211
var low = w[ 1 ];
// returns 2479577218
`
#### toWords.assign( x, out, stride, offset )
Splits a [double-precision floating-point number][ieee754] into a higher order word (unsigned 32-bit integer) and a lower order word (unsigned 32-bit integer) and assigns results to a provided output array.
`javascript
var Uint32Array = require( '@stdlib/array-uint32' );
var out = new Uint32Array( 2 );
var w = toWords.assign( 3.14e201, out, 1, 0 );
// returns
var bool = ( w === out );
// returns true
`
`javascript
var floor = require( '@stdlib/math-base-special-floor' );
var randu = require( '@stdlib/random-base-randu' );
var pow = require( '@stdlib/math-base-special-pow' );
var toWords = require( '@stdlib/number-float64-base-to-words' );
var frac;
var exp;
var w;
var x;
var i;
// Generate random numbers and split into words...
for ( i = 0; i < 100; i++ ) {
frac = randu() * 10.0;
exp = -floor( randu()*324.0 );
x = frac * pow( 10.0, exp );
w = toWords( x );
console.log( 'x: %d. higher: %d. lower: %d.', x, w[ 0 ], w[ 1 ] );
}
`
*
`c`
#include "stdlib/number/float64/base/to_words.h"
#### stdlib_base_float64_to_words( x, \high, \low )
Splits a double-precision floating-point number into a higher order word and a lower order word.
`c
#include
uint32_t high;
uint32_t low;
stdlib_base_float64_to_words( 3.14, &high, &low );
`
The function accepts the following arguments:
- x: [in] double input value.[out] uint32_t*
- high: destination for higher order word.[out] uint32_t*
- low: destination for lower order word.
`c`
void stdlib_base_float64_to_words( const double x, uint32_t high, uint32_t low );
#### stdlib_base_float64_words_t
An opaque type definition for a union for converting between a double-precision floating-point number and two unsigned 32-bit integers.
`c
#include
stdlib_base_float64_words_t w;
// Assign a double-precision floating-point number:
w.value = 3.14;
// Extract the high and low words:
uint32_t high = w.words.high;
uint32_t low = w.words.low;
`
The union has the following members:
- value: double double-precision floating-point number.
- words: struct struct having the following members:
- high: uint32_t higher order word.uint32_t
- low: lower order word.
`c
#include "stdlib/number/float64/base/to_words.h"
#include
#include
int main( void ) {
double x[] = { 3.14, -3.14, 0.0, 0.0/0.0 };
uint32_t high;
uint32_t low;
int i;
for ( i = 0; i < 4; i++ ) {
stdlib_base_float64_to_words( x[ i ], &high, &low );
printf( "%lf => high: %u, low: %u\n", x[ i ], high, low );
}
}
`
*
- [@stdlib/number-float64/base/from-words][@stdlib/number/float64/base/from-words]: create a double-precision floating-point number from a higher order word and a lower order word.
- [@stdlib/number-float32/base/to-word][@stdlib/number/float32/base/to-word]: return an unsigned 32-bit integer corresponding to the IEEE 754 binary representation of a single-precision floating-point number.
*
This package is part of [stdlib][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][stdlib], see the main project [repository][stdlib].
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---
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