math-float64-from-words

toFloat64

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

Installation

$ npm install math-float64-from-words

Usage

var toFloat64 = require( 'math-float64-from-words' );

toFloat64( 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 val = toFloat64( 1774486211, 2479577218 );
// returns 3.14e201

val = toFloat64( 3221823995, 1413754136 );
// returns 3.141592653589793

val = toFloat64( 0, 0 );
// returns 0

val = toFloat64( 2147483648, 0 );
// returns -0

val = toFloat64( 2146959360, 0 );
// returns NaN

val = toFloat64( 2146435072, 0 );
// returns +infinity

val = toFloat64( 4293918720, 0 );
// returns -infinity

Notes

• For more information regarding higher and lower order words, see math-float64-to-words.

Examples

var round = require( 'math-round' );
var pow = require( 'math-power' );
var toFloat64 = require( 'math-float64-from-words' );

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

MAX_UINT = pow( 2, 32 ) - 1;
for ( i = 0; i < 100; i++ ) {
	high = round( Math.random()*MAX_UINT );
	low = round( Math.random()*MAX_UINT );
	x = toFloat64( high, low );
	console.log( 'higher: %d. lower: %d. float: %d.', high, low, x );
}

To run the example code from the top-level application directory,

$ node ./examples/index.js

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Tests

Unit

This repository uses tape for unit tests. To run the tests, execute the following command in the top-level application directory:

$ make test

All new feature development should have corresponding unit tests to validate correct functionality.

Test Coverage

This repository uses Istanbul as its code coverage tool. To generate a test coverage report, execute the following command in the top-level application directory:

$ make test-cov

Istanbul creates a ./reports/coverage directory. To access an HTML version of the report,

$ make view-cov

Browser Support

This repository uses Testling for browser testing. To run the tests in a (headless) local web browser, execute the following command in the top-level application directory:

$ make test-browsers

To view the tests in a local web browser,

$ make view-browser-tests

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License

MIT license.

Copyright

Copyright © 2016. The Compute.io Authors.