linux/arch/arm64/lib/crc32.S

61 lines
1.2 KiB
ArmAsm

/*
* 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
0: subs x2, x2, #16
b.mi 8f
ldp x3, x4, [x1], #16
CPU_BE( rev x3, x3 )
CPU_BE( rev x4, x4 )
crc32\c\()x w0, w0, x3
crc32\c\()x w0, w0, x4
b.ne 0b
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)