intparts

Manipulate the integer parts of a JS Number, including frexp and ldexp.

Author(s)

Christoph Zurnieden [e-mail]

Installation

$ git clone https://github.com/czurnieden/intparts.git
$ cd intparts
$ npm install -g

There is also a Unix (or newer Macs) dependent CLI version in ./bin.

Please be aware that this module assumes little endian.

Version

0.0.1 Initial publication

Description

This library implements some of the functions to inspect the innards of a 64 bit double, the default type in ECMAScript up to version 5.1 at least. It allows direct manipulation of the bits in a Number. Included are ports of C-lib's frexp and ldexp.

This module runs as ams.js where applicable.

Usage

The usage is like with any other node/browser module:

var ip = require('intparts');
var raw_exponent = ip.getexponent(123.312); // 0x405
var unbiased_exponent = ip.frexp(123.321)[1]; // 7

This program offers ten functions which are in alphabetical order:

frexp(number)

Return: an Uint32Array containing the mantissa and the exponent in that order such that mantissa * 2^exponent = number

getexponent(number)

Return: the biased, raw exponent in hexadecimal representation

gethigh(number)

Return: the high word in hexadecimal representation

getlow(number)

Return: the low word in hexadecimal representation

getsign(number)

Return: the sign bit in hexadecimal representation

getwords(number)

Return: the comma separated low and high words in hexadecimal representation and in that order

ldexp(mantissa,exponent)

Return: a number such that mantissa * 2^exponent = number

sethigh(integer,number)

Sets the high word of number

Return: the manipulated number

setlow(integer,number)

Sets the high word of number

Return: the manipulated number

setwords(number,high_integer,low_integer)

Sets the words of number

Return: the manipulated number

This module does no error catching.

Example

No example yet, but ideas are welcome.