From Words

Create a double-precision floating-point number from a higher order word and a lower order word.

Usage

var fromWords = require( '@stdlib/number/float64/base/from-words' );

fromWords( high, low )

Creates a double-precision floating-point number from a higher order word (unsigned 32-bit integer) and a lower order word (unsigned 32-bit integer).

var v = fromWords( 1774486211, 2479577218 );
// returns 3.14e201

v = fromWords( 3221823995, 1413754136 );
// returns -3.141592653589793

v = fromWords( 0, 0 );
// returns 0.0

v = fromWords( 2147483648, 0 );
// returns -0.0

v = fromWords( 2146959360, 0 );
// returns NaN

v = fromWords( 2146435072, 0 );
// returns Infinity

v = fromWords( 4293918720, 0 );
// returns -Infinity

Notes

For more information regarding higher and lower order words, see to-words.

Examples

var randu = require( '@stdlib/random/base/randu' );
var round = require( '@stdlib/math/base/special/round' );
var MAX_UINT32 = require( '@stdlib/constants/uint32/max' );
var fromWords = require( '@stdlib/number/float64/base/from-words' );

var high;
var low;
var x;
var i;

for ( i = 0; i < 100; i++ ) {
    high = round( randu()*MAX_UINT32 );
    low = round( randu()*MAX_UINT32 );
    x = fromWords( high, low );
    console.log( 'higher: %d. lower: %d. float: %d.', high, low, x );
}

C APIs

Usage

#include "stdlib/number/float64/base/from_words.h"

stdlib_base_float64_from_words( high, low, *x )

Creates a double-precision floating-point number from a higher order word and a lower order word.

#include <stdint.h>

uint32_t high = 1074339512;
uint32_t low = 1374389535;

double x;
stdlib_base_float64_from_words( high, low, &x );

The function accepts the following arguments:

high: [in] uint32_t higher order word.
low: [in] uint32_t lower order word.
x: [out] double* destination for a double-precision floating-point number.

void stdlib_base_float64_from_words( const uint32_t high, const uint32_t low, double *x );

Examples

#include "stdlib/number/float64/base/from_words.h"
#include <stdint.h>
#include <stdio.h>

int main( void ) {
    uint32_t high = 1074339512;
    uint32_t low[] = { 0, 10000, 1000000, 1374389535 };

    double x;
    int i;
    for ( i = 0; i < 4; i++ ) {
        stdlib_base_float64_from_words( high, low[ i ], &x );
        printf( "high: %u, low: %u => %lf\n", high, low[ i ], x );
    }
}