tail:
	CMPBEQ	R4, $0, done
	MOVB	0(R2)(R5*1), R7
	MOVB	0(R3)(R5*1), R8
	XOR	R7, R8
	MOVB	R8, 0(R1)(R5*1)
	LAY	1(R5), R5
	SUB	$1, R4
	BR	tail
done:
	RET

// func cryptBlocksGCM(fn code, key, dst, src, buf []byte, cnt *[16]byte)
TEXT ·cryptBlocksGCM(SB),NOSPLIT,$0-112
	MOVD	src_len+64(FP), R0
	MOVD	buf_base+80(FP), R1
	MOVD	cnt+104(FP), R12
	LMG	(R12), R2, R3

	if siz > 0 {
		ghash(&g.hashKey, hash, data[:siz])
		data = data[siz:]
	}
	if len(data) > 0 {
		var s [16]byte
		copy(s[:], data)
		ghash(&g.hashKey, hash, s[:])
	}
}

// cryptBlocksGCM encrypts src using AES in counter mode using the given
// function code and key. The rightmost 32-bits of the counter are incremented
// between each block as required by the GCM spec. The initial counter value