function subf( x, y ) {
	return addon( x, y );
}
Subtracts two single-precision floating-point numbers `x` and `y`.

@private
@param {number} x - first input value
@param {number} y - second input value
@returns {number} result

@example
var v = subf( -1.0, 5.0 );
// returns -6.0

@example
var v = subf( 2.0, 5.0 );
// returns -3.0

@example
var v = subf( 0.0, 5.0 );
// returns -5.0

@example
var v = subf( -0.0, 0.0 );
// returns -0.0

@example
var v = subf( NaN, NaN );
// returns NaN