/* GPL HEADER START
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*
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 only,
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* as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License version 2 for more details (a copy is included
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* in the LICENSE file that accompanied this code).
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*
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* You should have received a copy of the GNU General Public License
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* version 2 along with this program; If not, see http://www.gnu.org/licenses
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*
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* Please visit http://www.xyratex.com/contact if you need additional
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* information or have any questions.
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*
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* GPL HEADER END
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*/
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/*
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* Copyright 2012 Xyratex Technology Limited
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*
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* Using hardware provided PCLMULQDQ instruction to accelerate the CRC32
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* calculation.
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* CRC32 polynomial:0x04c11db7(BE)/0xEDB88320(LE)
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* PCLMULQDQ is a new instruction in Intel SSE4.2, the reference can be found
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* at:
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* http://www.intel.com/products/processor/manuals/
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* Intel(R) 64 and IA-32 Architectures Software Developer's Manual
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* Volume 2B: Instruction Set Reference, N-Z
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*
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* Authors: Gregory Prestas <Gregory_Prestas@us.xyratex.com>
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* Alexander Boyko <Alexander_Boyko@xyratex.com>
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*/
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#include <linux/linkage.h>
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.section .rodata
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.align 16
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/*
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* [x4*128+32 mod P(x) << 32)]' << 1 = 0x154442bd4
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* #define CONSTANT_R1 0x154442bd4LL
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*
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* [(x4*128-32 mod P(x) << 32)]' << 1 = 0x1c6e41596
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* #define CONSTANT_R2 0x1c6e41596LL
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*/
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.Lconstant_R2R1:
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.octa 0x00000001c6e415960000000154442bd4
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/*
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* [(x128+32 mod P(x) << 32)]' << 1 = 0x1751997d0
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* #define CONSTANT_R3 0x1751997d0LL
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*
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* [(x128-32 mod P(x) << 32)]' << 1 = 0x0ccaa009e
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* #define CONSTANT_R4 0x0ccaa009eLL
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*/
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.Lconstant_R4R3:
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.octa 0x00000000ccaa009e00000001751997d0
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/*
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* [(x64 mod P(x) << 32)]' << 1 = 0x163cd6124
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* #define CONSTANT_R5 0x163cd6124LL
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*/
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.Lconstant_R5:
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.octa 0x00000000000000000000000163cd6124
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.Lconstant_mask32:
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.octa 0x000000000000000000000000FFFFFFFF
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/*
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* #define CRCPOLY_TRUE_LE_FULL 0x1DB710641LL
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*
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* Barrett Reduction constant (u64`) = u` = (x**64 / P(x))` = 0x1F7011641LL
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* #define CONSTANT_RU 0x1F7011641LL
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*/
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.Lconstant_RUpoly:
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.octa 0x00000001F701164100000001DB710641
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#define CONSTANT %xmm0
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#ifdef __x86_64__
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#define BUF %rdi
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#define LEN %rsi
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#define CRC %edx
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#else
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#define BUF %eax
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#define LEN %edx
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#define CRC %ecx
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#endif
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.text
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/**
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* Calculate crc32
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* BUF - buffer (16 bytes aligned)
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* LEN - sizeof buffer (16 bytes aligned), LEN should be grater than 63
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* CRC - initial crc32
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* return %eax crc32
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* uint crc32_pclmul_le_16(unsigned char const *buffer,
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* size_t len, uint crc32)
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*/
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SYM_FUNC_START(crc32_pclmul_le_16) /* buffer and buffer size are 16 bytes aligned */
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movdqa (BUF), %xmm1
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movdqa 0x10(BUF), %xmm2
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movdqa 0x20(BUF), %xmm3
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movdqa 0x30(BUF), %xmm4
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movd CRC, CONSTANT
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pxor CONSTANT, %xmm1
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sub $0x40, LEN
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add $0x40, BUF
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cmp $0x40, LEN
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jb less_64
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#ifdef __x86_64__
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movdqa .Lconstant_R2R1(%rip), CONSTANT
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#else
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movdqa .Lconstant_R2R1, CONSTANT
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#endif
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loop_64:/* 64 bytes Full cache line folding */
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prefetchnta 0x40(BUF)
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movdqa %xmm1, %xmm5
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movdqa %xmm2, %xmm6
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movdqa %xmm3, %xmm7
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#ifdef __x86_64__
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movdqa %xmm4, %xmm8
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#endif
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pclmulqdq $0x00, CONSTANT, %xmm1
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pclmulqdq $0x00, CONSTANT, %xmm2
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pclmulqdq $0x00, CONSTANT, %xmm3
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#ifdef __x86_64__
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pclmulqdq $0x00, CONSTANT, %xmm4
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#endif
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pclmulqdq $0x11, CONSTANT, %xmm5
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pclmulqdq $0x11, CONSTANT, %xmm6
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pclmulqdq $0x11, CONSTANT, %xmm7
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#ifdef __x86_64__
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pclmulqdq $0x11, CONSTANT, %xmm8
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#endif
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pxor %xmm5, %xmm1
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pxor %xmm6, %xmm2
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pxor %xmm7, %xmm3
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#ifdef __x86_64__
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pxor %xmm8, %xmm4
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#else
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/* xmm8 unsupported for x32 */
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movdqa %xmm4, %xmm5
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pclmulqdq $0x00, CONSTANT, %xmm4
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pclmulqdq $0x11, CONSTANT, %xmm5
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pxor %xmm5, %xmm4
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#endif
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pxor (BUF), %xmm1
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pxor 0x10(BUF), %xmm2
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pxor 0x20(BUF), %xmm3
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pxor 0x30(BUF), %xmm4
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sub $0x40, LEN
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add $0x40, BUF
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cmp $0x40, LEN
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jge loop_64
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less_64:/* Folding cache line into 128bit */
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#ifdef __x86_64__
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movdqa .Lconstant_R4R3(%rip), CONSTANT
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#else
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movdqa .Lconstant_R4R3, CONSTANT
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#endif
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prefetchnta (BUF)
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movdqa %xmm1, %xmm5
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pclmulqdq $0x00, CONSTANT, %xmm1
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pclmulqdq $0x11, CONSTANT, %xmm5
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pxor %xmm5, %xmm1
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pxor %xmm2, %xmm1
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movdqa %xmm1, %xmm5
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pclmulqdq $0x00, CONSTANT, %xmm1
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pclmulqdq $0x11, CONSTANT, %xmm5
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pxor %xmm5, %xmm1
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pxor %xmm3, %xmm1
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movdqa %xmm1, %xmm5
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pclmulqdq $0x00, CONSTANT, %xmm1
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pclmulqdq $0x11, CONSTANT, %xmm5
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pxor %xmm5, %xmm1
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pxor %xmm4, %xmm1
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cmp $0x10, LEN
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jb fold_64
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loop_16:/* Folding rest buffer into 128bit */
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movdqa %xmm1, %xmm5
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pclmulqdq $0x00, CONSTANT, %xmm1
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pclmulqdq $0x11, CONSTANT, %xmm5
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pxor %xmm5, %xmm1
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pxor (BUF), %xmm1
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sub $0x10, LEN
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add $0x10, BUF
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cmp $0x10, LEN
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jge loop_16
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fold_64:
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/* perform the last 64 bit fold, also adds 32 zeroes
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* to the input stream */
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pclmulqdq $0x01, %xmm1, CONSTANT /* R4 * xmm1.low */
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psrldq $0x08, %xmm1
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pxor CONSTANT, %xmm1
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/* final 32-bit fold */
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movdqa %xmm1, %xmm2
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#ifdef __x86_64__
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movdqa .Lconstant_R5(%rip), CONSTANT
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movdqa .Lconstant_mask32(%rip), %xmm3
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#else
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movdqa .Lconstant_R5, CONSTANT
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movdqa .Lconstant_mask32, %xmm3
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#endif
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psrldq $0x04, %xmm2
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pand %xmm3, %xmm1
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pclmulqdq $0x00, CONSTANT, %xmm1
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pxor %xmm2, %xmm1
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/* Finish up with the bit-reversed barrett reduction 64 ==> 32 bits */
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#ifdef __x86_64__
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movdqa .Lconstant_RUpoly(%rip), CONSTANT
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#else
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movdqa .Lconstant_RUpoly, CONSTANT
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#endif
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movdqa %xmm1, %xmm2
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pand %xmm3, %xmm1
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pclmulqdq $0x10, CONSTANT, %xmm1
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pand %xmm3, %xmm1
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pclmulqdq $0x00, CONSTANT, %xmm1
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pxor %xmm2, %xmm1
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pextrd $0x01, %xmm1, %eax
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RET
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SYM_FUNC_END(crc32_pclmul_le_16)
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