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freebsd
GitHub Repository: freebsd/freebsd-src
 Path: blob/main/sys/libkern/arm64/crc32c_armv8.S
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/*-

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 * Copyright (c) 2017 Michael Tuexen

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 * All rights reserved.

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 *

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 * Redistribution and use in source and binary forms, with or without

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 * modification, are permitted provided that the following conditions

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 * are met:

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 * 1. Redistributions of source code must retain the above copyright

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 *    notice, this list of conditions and the following disclaimer.

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 * 2. Redistributions in binary form must reproduce the above copyright

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 *    notice, this list of conditions and the following disclaimer in the

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 *    documentation and/or other materials provided with the distribution.

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 *

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 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND

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 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

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 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

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 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE

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 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL

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 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS

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 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)

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 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT

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 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY

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 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF

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 * SUCH DAMAGE.

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 *

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 */

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#include <machine/asm.h>

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#include <sys/elf_common.h>

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.arch_extension crc

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/*

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 * uint32_t

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 * armv8_crc32c(uint32_t crc, const unsigned char *buf, unsigned int len)

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 */

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ENTRY(armv8_crc32c)

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	cbz	w2, end

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	tbz	x1, #0x0, half_word_aligned

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	sub	w2, w2, 0x1

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	ldr	w10, [x1], #0x1

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	crc32cb	w0, w0, w10

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half_word_aligned:

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	cmp	w2, #0x2

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	b.lo	last_byte

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	tbz	x1, #0x1, word_aligned

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	sub	w2, w2, 0x2

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	ldr	w10, [x1], #0x2

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	crc32ch	w0, w0, w10

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word_aligned:

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	cmp	w2, #0x4

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	b.lo	last_half_word

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	tbz	x1, #0x2, double_word_aligned

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	sub	w2, w2, 0x4

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	ldr	w10, [x1], #0x4

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	crc32cw	w0, w0, w10

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double_word_aligned:

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	lsr	w9, w2, #0x3

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	cbz	w9, last_word

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loop:

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	ldr	x10, [x1], #0x8

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	crc32cx	w0, w0, x10

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	subs	w9, w9, #1

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	b.ne	loop

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last_word:

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	tbz	w2, #0x2, last_half_word

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	ldr	w10, [x1], #0x4

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	crc32cw	w0, w0, w10

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last_half_word:

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	tbz	w2, #0x1, last_byte

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	ldr	w10, [x1], #0x2

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	crc32ch	w0, w0, w10

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last_byte:

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	tbz	w2, #0x0, end 

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	ldr	w10, [x1], #0x1

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	crc32cb	w0, w0, w10

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end:

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	ret

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END(armv8_crc32c)

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GNU_PROPERTY_AARCH64_FEATURE_1_NOTE(GNU_PROPERTY_AARCH64_FEATURE_1_VAL)

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