// tagMask and writes the result to out.
func (g *gcmAsm) auth(out, ciphertext, aad []byte, tagMask *[gcmTagSize]byte) {
	var hash [16]byte
	g.paddedGHASH(&hash, aad)
	g.paddedGHASH(&hash, ciphertext)
	lens := gcmLengths(uint64(len(aad))*8, uint64(len(ciphertext))*8)
	g.paddedGHASH(&hash, lens[:])

	copy(out, hash[:])
	for i := range out {
		out[i] ^= tagMask[i]
	}
}

func (g *gcmAsm) auth(out, ciphertext, additionalData []byte, tagMask *[gcmTagSize]byte) {
	var hash [16]byte
	g.paddedGHASH(&hash, additionalData)
	g.paddedGHASH(&hash, ciphertext)
	lens := gcmLengths(uint64(len(additionalData))*8, uint64(len(ciphertext))*8)
	g.paddedGHASH(&hash, lens[:])

	copy(out, hash[:])
	for i := range out {
		out[i] ^= tagMask[i]
	}
}