Function change_sign

Source/astcenc_vecmathlib.h:275–282

* @brief Return @c a with lanes negated if the @c b lane is negative. */

 * @brief Return @c a with lanes negated if the @c b lane is negative.
 */
ASTCENC_SIMD_INLINE vfloat change_sign(vfloat a, vfloat b)
{
	vint ia = float_as_int(a);
	vint ib = float_as_int(b);
	vint sign_mask(static_cast<int>(0x80000000));
	vint r = ia ^ (ib & sign_mask);
	return int_as_float(r);
}

/**
 * @brief Return fast, but approximate, vector atan(x).