function ldexpf( frac, exp ) {
	return addon( frac, exp );
}
Multiplies a single-precision floating-point number by an integer power of two.

@private
@param {number} frac - fraction
@param {integer} exp - exponent
@returns {number} single-precision floating-point number

@example
var x = ldexpf( 0.5, 3 ); // => 0.5 * 2^3 = 0.5 * 8
// returns 4.0

@example
var x = ldexpf( 4.0, -2 ); // => 4 * 2^(-2) = 4 * (1/4)
// returns 1.0

@example
var x = ldexpf( 0.0, 20 );
// returns 0.0

@example
var x = ldexpf( -0.0, 39 );
// returns -0.0

@example
var x = ldexpf( NaN, -101 );
// returns NaN

@example
var x = ldexpf( Infinity, 11 );
// returns Infinity

@example
var x = ldexpf( -Infinity, -118 );
// returns -Infinity