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// Copyright 2020 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
#include "textflag.h"
// func xorBytesARM64(dst, a, b *byte, n int)
TEXT ·xorBytesARM64(SB), NOSPLIT|NOFRAME, $0
MOVD dst+0(FP), R0
MOVD a+8(FP), R1
MOVD b+16(FP), R2
MOVD n+24(FP), R3
CMP $64, R3
BLT tail
loop_64:
VLD1.P 64(R1), [V0.B16, V1.B16, V2.B16, V3.B16]
VLD1.P 64(R2), [V4.B16, V5.B16, V6.B16, V7.B16]
VEOR V0.B16, V4.B16, V4.B16
VEOR V1.B16, V5.B16, V5.B16
VEOR V2.B16, V6.B16, V6.B16
VEOR V3.B16, V7.B16, V7.B16
VST1.P [V4.B16, V5.B16, V6.B16, V7.B16], 64(R0)
SUBS $64, R3
CMP $64, R3
BGE loop_64
tail:
// quick end
CBZ R3, end
TBZ $5, R3, less_than32
VLD1.P 32(R1), [V0.B16, V1.B16]
VLD1.P 32(R2), [V2.B16, V3.B16]
VEOR V0.B16, V2.B16, V2.B16
VEOR V1.B16, V3.B16, V3.B16
VST1.P [V2.B16, V3.B16], 32(R0)
less_than32:
TBZ $4, R3, less_than16
LDP.P 16(R1), (R11, R12)
LDP.P 16(R2), (R13, R14)
EOR R11, R13, R13
EOR R12, R14, R14
STP.P (R13, R14), 16(R0)
less_than16:
TBZ $3, R3, less_than8
MOVD.P 8(R1), R11
MOVD.P 8(R2), R12
EOR R11, R12, R12
MOVD.P R12, 8(R0)
less_than8:
TBZ $2, R3, less_than4
MOVWU.P 4(R1), R13
MOVWU.P 4(R2), R14
EORW R13, R14, R14
MOVWU.P R14, 4(R0)
less_than4:
TBZ $1, R3, less_than2
MOVHU.P 2(R1), R15
MOVHU.P 2(R2), R16
EORW R15, R16, R16
MOVHU.P R16, 2(R0)
less_than2:
TBZ $0, R3, end
MOVBU (R1), R17
MOVBU (R2), R19
EORW R17, R19, R19
MOVBU R19, (R0)
end:
RET