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/*
* Accelerated CRC32(C) using AArch64 CRC instructions
*
* Copyright (C) 2016 - 2018 Linaro Ltd <ard.biesheuvel@linaro.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/linkage.h>
#include <asm/alternative.h>
#include <asm/assembler.h>
.cpu generic+crc
.macro __crc32, c
cmp x2, #16
b.lt 8f // less than 16 bytes
and x7, x2, #0x1f
and x2, x2, #~0x1f
cbz x7, 32f // multiple of 32 bytes
and x8, x7, #0xf
ldp x3, x4, [x1]
add x8, x8, x1
add x1, x1, x7
ldp x5, x6, [x8]
CPU_BE( rev x3, x3 )
CPU_BE( rev x4, x4 )
CPU_BE( rev x5, x5 )
CPU_BE( rev x6, x6 )
tst x7, #8
crc32\c\()x w8, w0, x3
csel x3, x3, x4, eq
csel w0, w0, w8, eq
tst x7, #4
lsr x4, x3, #32
crc32\c\()w w8, w0, w3
csel x3, x3, x4, eq
csel w0, w0, w8, eq
tst x7, #2
lsr w4, w3, #16
crc32\c\()h w8, w0, w3
csel w3, w3, w4, eq
csel w0, w0, w8, eq
tst x7, #1
crc32\c\()b w8, w0, w3
csel w0, w0, w8, eq
tst x7, #16
crc32\c\()x w8, w0, x5
crc32\c\()x w8, w8, x6
csel w0, w0, w8, eq
cbz x2, 0f
32: ldp x3, x4, [x1], #32
sub x2, x2, #32
ldp x5, x6, [x1, #-16]
CPU_BE( rev x3, x3 )
CPU_BE( rev x4, x4 )
CPU_BE( rev x5, x5 )
CPU_BE( rev x6, x6 )
crc32\c\()x w0, w0, x3
crc32\c\()x w0, w0, x4
crc32\c\()x w0, w0, x5
crc32\c\()x w0, w0, x6
cbnz x2, 32b
0: ret
8: tbz x2, #3, 4f
ldr x3, [x1], #8
CPU_BE( rev x3, x3 )
crc32\c\()x w0, w0, x3
4: tbz x2, #2, 2f
ldr w3, [x1], #4
CPU_BE( rev w3, w3 )
crc32\c\()w w0, w0, w3
2: tbz x2, #1, 1f
ldrh w3, [x1], #2
CPU_BE( rev16 w3, w3 )
crc32\c\()h w0, w0, w3
1: tbz x2, #0, 0f
ldrb w3, [x1]
crc32\c\()b w0, w0, w3
0: ret
.endm
.align 5
ENTRY(crc32_le)
alternative_if_not ARM64_HAS_CRC32
b crc32_le_base
alternative_else_nop_endif
__crc32
ENDPROC(crc32_le)
.align 5
ENTRY(__crc32c_le)
alternative_if_not ARM64_HAS_CRC32
b __crc32c_le_base
alternative_else_nop_endif
__crc32 c
ENDPROC(__crc32c_le)
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