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Text file src/crypto/subtle/xor_arm64.s

Documentation: crypto/subtle

     1// Copyright 2020 The Go Authors. All rights reserved.
     2// Use of this source code is governed by a BSD-style
     3// license that can be found in the LICENSE file.
     4
     5//go:build !purego
     6
     7#include "textflag.h"
     8
     9// func xorBytes(dst, a, b *byte, n int)
    10TEXT ·xorBytes(SB), NOSPLIT|NOFRAME, $0
    11	MOVD	dst+0(FP), R0
    12	MOVD	a+8(FP), R1
    13	MOVD	b+16(FP), R2
    14	MOVD	n+24(FP), R3
    15	CMP	$64, R3
    16	BLT	tail
    17loop_64:
    18	VLD1.P	64(R1), [V0.B16, V1.B16, V2.B16, V3.B16]
    19	VLD1.P	64(R2), [V4.B16, V5.B16, V6.B16, V7.B16]
    20	VEOR	V0.B16, V4.B16, V4.B16
    21	VEOR	V1.B16, V5.B16, V5.B16
    22	VEOR	V2.B16, V6.B16, V6.B16
    23	VEOR	V3.B16, V7.B16, V7.B16
    24	VST1.P	[V4.B16, V5.B16, V6.B16, V7.B16], 64(R0)
    25	SUBS	$64, R3
    26	CMP	$64, R3
    27	BGE	loop_64
    28tail:
    29	// quick end
    30	CBZ	R3, end
    31	TBZ	$5, R3, less_than32
    32	VLD1.P	32(R1), [V0.B16, V1.B16]
    33	VLD1.P	32(R2), [V2.B16, V3.B16]
    34	VEOR	V0.B16, V2.B16, V2.B16
    35	VEOR	V1.B16, V3.B16, V3.B16
    36	VST1.P	[V2.B16, V3.B16], 32(R0)
    37less_than32:
    38	TBZ	$4, R3, less_than16
    39	LDP.P	16(R1), (R11, R12)
    40	LDP.P	16(R2), (R13, R14)
    41	EOR	R11, R13, R13
    42	EOR	R12, R14, R14
    43	STP.P	(R13, R14), 16(R0)
    44less_than16:
    45	TBZ	$3, R3, less_than8
    46	MOVD.P	8(R1), R11
    47	MOVD.P	8(R2), R12
    48	EOR	R11, R12, R12
    49	MOVD.P	R12, 8(R0)
    50less_than8:
    51	TBZ	$2, R3, less_than4
    52	MOVWU.P	4(R1), R13
    53	MOVWU.P	4(R2), R14
    54	EORW	R13, R14, R14
    55	MOVWU.P	R14, 4(R0)
    56less_than4:
    57	TBZ	$1, R3, less_than2
    58	MOVHU.P	2(R1), R15
    59	MOVHU.P	2(R2), R16
    60	EORW	R15, R16, R16
    61	MOVHU.P	R16, 2(R0)
    62less_than2:
    63	TBZ	$0, R3, end
    64	MOVBU	(R1), R17
    65	MOVBU	(R2), R19
    66	EORW	R17, R19, R19
    67	MOVBU	R19, (R0)
    68end:
    69	RET

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