README.md

fromBinaryString

Create a half-precision floating-point number from an IEEE 754 literal bit representation.

Usage

var fromBinaryString = require( '@stdlib/number/float16/base/from-binary-string' );

fromBinaryString( bstr )

Creates a half-precision floating-point number from an IEEE 754 literal bit representation.

var bstr = '0100010000000000';
var v = fromBinaryString( bstr );
// returns 4.0

bstr = '0100001001001000';
v = fromBinaryString( bstr );
// returns ~3.140625

bstr = '1110001111010000';
v = fromBinaryString( bstr );
// returns -1000.0

The function handles subnormals.

var bstr = '1000000000000001';
var val = fromBinaryString( bstr );
// returns ~-5.96e-8

bstr = '0000000000000001';
val = fromBinaryString( bstr );
// returns ~5.96e-8

The function handles special values.

var bstr = '0000000000000000';
var val = fromBinaryString( bstr );
// returns 0.0

bstr = '1000000000000000';
val = fromBinaryString( bstr );
// returns -0.0

bstr = '0111111000000000';
val = fromBinaryString( bstr );
// returns NaN

bstr = '0111110000000000';
val = fromBinaryString( bstr );
// returns Infinity

bstr = '1111110000000000';
val = fromBinaryString( bstr );
// returns -Infinity

Examples

var randu = require( '@stdlib/random/base/randu' );
var round = require( '@stdlib/math/base/special/round' );
var pow = require( '@stdlib/math/base/special/pow' );
var toFloat16 = require( '@stdlib/number/float64/base/to-float16' );
var toBinaryString = require( '@stdlib/number/float16/base/to-binary-string' );
var fromBinaryString = require( '@stdlib/number/float16/base/from-binary-string' );

var frac;
var sign;
var exp;
var b;
var x;
var y;
var i;

// Convert random numbers to IEEE 754 literal bit representations and then convert them back...
for ( i = 0; i < 100; i++ ) {
    if ( randu() < 0.5 ) {
        sign = -1.0;
    } else {
        sign = 1.0;
    }
    frac = randu() * 10.0;
    exp = round( randu()*5.0 );
    if ( randu() < 0.5 ) {
        exp = -exp;
    }
    x = sign * frac * pow( 2.0, exp );
    x = toFloat16( x );

    b = toBinaryString( x );
    y = fromBinaryString( b );

    console.log( '%d => %s => %d', x, b, y );
    console.log( x === y );
}