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https://git.tukaani.org/xz.git
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liblzma: Moved CLMUL CRC logic to crc_common.h.
crc64_fast.c was updated to use the code from crc_common.h instead.
This commit is contained in:
parent
233885a437
commit
93e6fb08b2
2 changed files with 240 additions and 247 deletions
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@ -10,9 +10,9 @@
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///
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///
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/// crc64_clmul uses 32/64-bit x86 SSSE3, SSE4.1, and CLMUL instructions.
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/// crc64_clmul uses 32/64-bit x86 SSSE3, SSE4.1, and CLMUL instructions.
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/// It was derived from
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/// It was derived from
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/// https://www.intel.com/content/dam/www/public/us/en/documents/white-papers/fast-crc-computation-generic-polynomials-pclmulqdq-paper.pdf
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/// https://www.researchgate.net/publication/263424619_Fast_CRC_computation
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/// and the public domain code from https://github.com/rawrunprotected/crc
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/// and the public domain code from https://github.com/rawrunprotected/crc
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/// (URLs were checked on 2022-11-07).
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/// (URLs were checked on 2023-09-29).
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///
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///
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/// FIXME: Builds for 32-bit x86 use crc64_x86.S by default instead
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/// FIXME: Builds for 32-bit x86 use crc64_x86.S by default instead
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/// of this file and thus CLMUL version isn't available on 32-bit x86
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/// of this file and thus CLMUL version isn't available on 32-bit x86
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@ -29,47 +29,7 @@
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///////////////////////////////////////////////////////////////////////////////
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///////////////////////////////////////////////////////////////////////////////
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#include "check.h"
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#include "check.h"
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#include "crc_common.h"
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#undef CRC_GENERIC
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#undef CRC_CLMUL
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#undef CRC_USE_GENERIC_FOR_SMALL_INPUTS
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// If CLMUL cannot be used then only the generic slice-by-four is built.
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#if !defined(HAVE_USABLE_CLMUL)
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# define CRC_GENERIC 1
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// If CLMUL is allowed unconditionally in the compiler options then the
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// generic version can be omitted. Note that this doesn't work with MSVC
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// as I don't know how to detect the features here.
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//
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// NOTE: Keep this this in sync with crc64_table.c.
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#elif (defined(__SSSE3__) && defined(__SSE4_1__) && defined(__PCLMUL__)) \
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|| (defined(__e2k__) && __iset__ >= 6)
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# define CRC_CLMUL 1
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// Otherwise build both and detect at runtime which version to use.
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#else
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# define CRC_GENERIC 1
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# define CRC_CLMUL 1
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/*
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// The generic code is much faster with 1-8-byte inputs and has
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// similar performance up to 16 bytes at least in microbenchmarks
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// (it depends on input buffer alignment too). If both versions are
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// built, this #define will use the generic version for inputs up to
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// 16 bytes and CLMUL for bigger inputs. It saves a little in code
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// size since the special cases for 0-16-byte inputs will be omitted
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// from the CLMUL code.
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# define CRC_USE_GENERIC_FOR_SMALL_INPUTS 1
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*/
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# if defined(_MSC_VER)
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# include <intrin.h>
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# elif defined(HAVE_CPUID_H)
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# include <cpuid.h>
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# endif
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#endif
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/////////////////////////////////
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/////////////////////////////////
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// Generic slice-by-four CRC64 //
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// Generic slice-by-four CRC64 //
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@ -77,8 +37,6 @@
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#ifdef CRC_GENERIC
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#ifdef CRC_GENERIC
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#include "crc_common.h"
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#ifdef WORDS_BIGENDIAN
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#ifdef WORDS_BIGENDIAN
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# define A1(x) ((x) >> 56)
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# define A1(x) ((x) >> 56)
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@ -173,17 +131,6 @@ calc_hi(uint64_t poly, uint64_t a)
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*/
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*/
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#define MASK_L(in, mask, r) \
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r = _mm_shuffle_epi8(in, mask)
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#define MASK_H(in, mask, r) \
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r = _mm_shuffle_epi8(in, _mm_xor_si128(mask, vsign))
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#define MASK_LH(in, mask, low, high) \
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MASK_L(in, mask, low); \
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MASK_H(in, mask, high)
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// MSVC (VS2015 - VS2022) produces bad 32-bit x86 code from the CLMUL CRC
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// MSVC (VS2015 - VS2022) produces bad 32-bit x86 code from the CLMUL CRC
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// code when optimizations are enabled (release build). According to the bug
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// code when optimizations are enabled (release build). According to the bug
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// report, the ebx register is corrupted and the calculated result is wrong.
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// report, the ebx register is corrupted and the calculated result is wrong.
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@ -206,14 +153,6 @@ calc_hi(uint64_t poly, uint64_t a)
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#if (defined(__GNUC__) || defined(__clang__)) && !defined(__EDG__)
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#if (defined(__GNUC__) || defined(__clang__)) && !defined(__EDG__)
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__attribute__((__target__("ssse3,sse4.1,pclmul")))
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__attribute__((__target__("ssse3,sse4.1,pclmul")))
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#endif
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#endif
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// The intrinsics use 16-byte-aligned reads from buf, thus they may read
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// up to 15 bytes before or after the buffer (depending on the alignment
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// of the buf argument). The values of the extra bytes are ignored.
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// This unavoidably trips -fsanitize=address so address sanitizier has
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// to be disabled for this function.
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#if lzma_has_attribute(__no_sanitize_address__)
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__attribute__((__no_sanitize_address__))
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#endif
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static uint64_t
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static uint64_t
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crc64_clmul(const uint8_t *buf, size_t size, uint64_t crc)
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crc64_clmul(const uint8_t *buf, size_t size, uint64_t crc)
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{
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{
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@ -237,150 +176,24 @@ crc64_clmul(const uint8_t *buf, size_t size, uint64_t crc)
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const uint64_t mu = 0x9c3e466c172963d5; // (calc_lo(poly) << 1) | 1
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const uint64_t mu = 0x9c3e466c172963d5; // (calc_lo(poly) << 1) | 1
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const uint64_t k2 = 0xdabe95afc7875f40; // calc_hi(poly, 1)
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const uint64_t k2 = 0xdabe95afc7875f40; // calc_hi(poly, 1)
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const uint64_t k1 = 0xe05dd497ca393ae4; // calc_hi(poly, k2)
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const uint64_t k1 = 0xe05dd497ca393ae4; // calc_hi(poly, k2)
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const __m128i vfold0 = _mm_set_epi64x(p, mu);
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const __m128i vfold1 = _mm_set_epi64x(k2, k1);
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// Create a vector with 8-bit values 0 to 15. This is used to
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const __m128i vfold8 = _mm_set_epi64x(p, mu);
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// construct control masks for _mm_blendv_epi8 and _mm_shuffle_epi8.
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const __m128i vfold16 = _mm_set_epi64x(k2, k1);
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const __m128i vramp = _mm_setr_epi32(
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0x03020100, 0x07060504, 0x0b0a0908, 0x0f0e0d0c);
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// This is used to inverse the control mask of _mm_shuffle_epi8
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__m128i v0, v1, v2;
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// so that bytes that wouldn't be picked with the original mask
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// will be picked and vice versa.
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const __m128i vsign = _mm_set1_epi8(0x80);
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// Memory addresses A to D and the distances between them:
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//
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// A B C D
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// [skip_start][size][skip_end]
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// [ size2 ]
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//
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// A and D are 16-byte aligned. B and C are 1-byte aligned.
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// skip_start and skip_end are 0-15 bytes. size is at least 1 byte.
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//
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// A = aligned_buf will initially point to this address.
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// B = The address pointed by the caller-supplied buf.
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// C = buf + size == aligned_buf + size2
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// D = buf + size + skip_end == aligned_buf + size2 + skip_end
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const size_t skip_start = (size_t)((uintptr_t)buf & 15);
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const size_t skip_end = (size_t)((0U - (uintptr_t)(buf + size)) & 15);
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const __m128i *aligned_buf = (const __m128i *)(
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(uintptr_t)buf & ~(uintptr_t)15);
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// If size2 <= 16 then the whole input fits into a single 16-byte
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// vector. If size2 > 16 then at least two 16-byte vectors must
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// be processed. If size2 > 16 && size <= 16 then there is only
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// one 16-byte vector's worth of input but it is unaligned in memory.
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//
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// NOTE: There is no integer overflow here if the arguments are valid.
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// If this overflowed, buf + size would too.
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size_t size2 = skip_start + size;
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// Masks to be used with _mm_blendv_epi8 and _mm_shuffle_epi8:
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// The first skip_start or skip_end bytes in the vectors will have
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// the high bit (0x80) set. _mm_blendv_epi8 and _mm_shuffle_epi8
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// will produce zeros for these positions. (Bitwise-xor of these
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// masks with vsign will produce the opposite behavior.)
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const __m128i mask_start
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= _mm_sub_epi8(vramp, _mm_set1_epi8(skip_start));
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const __m128i mask_end = _mm_sub_epi8(vramp, _mm_set1_epi8(skip_end));
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// Get the first 1-16 bytes into data0. If loading less than 16 bytes,
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// the bytes are loaded to the high bits of the vector and the least
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// significant positions are filled with zeros.
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const __m128i data0 = _mm_blendv_epi8(_mm_load_si128(aligned_buf),
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_mm_setzero_si128(), mask_start);
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++aligned_buf;
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#if defined(__i386__) || defined(_M_IX86)
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#if defined(__i386__) || defined(_M_IX86)
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const __m128i initial_crc = _mm_set_epi64x(0, ~crc);
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crc_simd_body(buf, size, &v0, &v1, vfold16, _mm_set_epi64x(0, ~crc));
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#else
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#else
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// GCC and Clang would produce good code with _mm_set_epi64x
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// GCC and Clang would produce good code with _mm_set_epi64x
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// but MSVC needs _mm_cvtsi64_si128 on x86-64.
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// but MSVC needs _mm_cvtsi64_si128 on x86-64.
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const __m128i initial_crc = _mm_cvtsi64_si128(~crc);
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crc_simd_body(buf, size, &v0, &v1, vfold16, _mm_cvtsi64_si128(~crc));
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#endif
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#endif
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__m128i v0, v1, v2, v3;
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v1 = _mm_xor_si128(_mm_clmulepi64_si128(v0, vfold16, 0x10), v1);
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v0 = _mm_clmulepi64_si128(v1, vfold8, 0x00);
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#ifndef CRC_USE_GENERIC_FOR_SMALL_INPUTS
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v2 = _mm_clmulepi64_si128(v0, vfold8, 0x10);
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if (size <= 16) {
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v0 = _mm_xor_si128(_mm_xor_si128(v1, _mm_slli_si128(v0, 8)), v2);
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// Right-shift initial_crc by 1-16 bytes based on "size"
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// and store the result in v1 (high bytes) and v0 (low bytes).
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//
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// NOTE: The highest 8 bytes of initial_crc are zeros so
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// v1 will be filled with zeros if size >= 8. The highest 8
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// bytes of v1 will always become zeros.
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//
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// [ v1 ][ v0 ]
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// [ initial_crc ] size == 1
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// [ initial_crc ] size == 2
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// [ initial_crc ] size == 15
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// [ initial_crc ] size == 16 (all in v0)
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const __m128i mask_low = _mm_add_epi8(
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vramp, _mm_set1_epi8(size - 16));
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MASK_LH(initial_crc, mask_low, v0, v1);
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if (size2 <= 16) {
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// There are 1-16 bytes of input and it is all
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// in data0. Copy the input bytes to v3. If there
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// are fewer than 16 bytes, the low bytes in v3
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// will be filled with zeros. That is, the input
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// bytes are stored to the same position as
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// (part of) initial_crc is in v0.
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MASK_L(data0, mask_end, v3);
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} else {
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// There are 2-16 bytes of input but not all bytes
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// are in data0.
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const __m128i data1 = _mm_load_si128(aligned_buf);
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// Collect the 2-16 input bytes from data0 and data1
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// to v2 and v3, and bitwise-xor them with the
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// low bits of initial_crc in v0. Note that the
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// the second xor is below this else-block as it
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// is shared with the other branch.
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MASK_H(data0, mask_end, v2);
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MASK_L(data1, mask_end, v3);
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v0 = _mm_xor_si128(v0, v2);
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}
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v0 = _mm_xor_si128(v0, v3);
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v1 = _mm_alignr_epi8(v1, v0, 8);
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} else
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#endif
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{
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const __m128i data1 = _mm_load_si128(aligned_buf);
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MASK_LH(initial_crc, mask_start, v0, v1);
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v0 = _mm_xor_si128(v0, data0);
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v1 = _mm_xor_si128(v1, data1);
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#define FOLD \
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v1 = _mm_xor_si128(v1, _mm_clmulepi64_si128(v0, vfold1, 0x00)); \
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v0 = _mm_xor_si128(v1, _mm_clmulepi64_si128(v0, vfold1, 0x11));
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while (size2 > 32) {
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++aligned_buf;
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size2 -= 16;
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FOLD
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v1 = _mm_load_si128(aligned_buf);
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}
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if (size2 < 32) {
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MASK_H(v0, mask_end, v2);
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MASK_L(v0, mask_end, v0);
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MASK_L(v1, mask_end, v3);
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v1 = _mm_or_si128(v2, v3);
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}
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FOLD
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v1 = _mm_srli_si128(v0, 8);
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#undef FOLD
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}
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v1 = _mm_xor_si128(_mm_clmulepi64_si128(v0, vfold1, 0x10), v1);
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v0 = _mm_clmulepi64_si128(v1, vfold0, 0x00);
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v2 = _mm_clmulepi64_si128(v0, vfold0, 0x10);
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v0 = _mm_xor_si128(_mm_xor_si128(v2, _mm_slli_si128(v0, 8)), v1);
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#if defined(__i386__) || defined(_M_IX86)
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#if defined(__i386__) || defined(_M_IX86)
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return ~(((uint64_t)(uint32_t)_mm_extract_epi32(v0, 3) << 32) |
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return ~(((uint64_t)(uint32_t)_mm_extract_epi32(v0, 3) << 32) |
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@ -399,53 +212,7 @@ crc64_clmul(const uint8_t *buf, size_t size, uint64_t crc)
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#endif
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#endif
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#endif
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#endif
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////////////////////////
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// Detect CPU support //
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////////////////////////
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#if defined(CRC_GENERIC) && defined(CRC_CLMUL)
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#if defined(CRC_GENERIC) && defined(CRC_CLMUL)
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static inline bool
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is_clmul_supported(void)
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{
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int success = 1;
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uint32_t r[4]; // eax, ebx, ecx, edx
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#if defined(_MSC_VER)
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// This needs <intrin.h> with MSVC. ICC has it as a built-in
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// on all platforms.
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__cpuid(r, 1);
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#elif defined(HAVE_CPUID_H)
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// Compared to just using __asm__ to run CPUID, this also checks
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// that CPUID is supported and saves and restores ebx as that is
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// needed with GCC < 5 with position-independent code (PIC).
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success = __get_cpuid(1, &r[0], &r[1], &r[2], &r[3]);
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#else
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// Just a fallback that shouldn't be needed.
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__asm__("cpuid\n\t"
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: "=a"(r[0]), "=b"(r[1]), "=c"(r[2]), "=d"(r[3])
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: "a"(1), "c"(0));
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#endif
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// Returns true if these are supported:
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// CLMUL (bit 1 in ecx)
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// SSSE3 (bit 9 in ecx)
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// SSE4.1 (bit 19 in ecx)
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const uint32_t ecx_mask = (1 << 1) | (1 << 9) | (1 << 19);
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return success && (r[2] & ecx_mask) == ecx_mask;
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// Alternative methods that weren't used:
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// - ICC's _may_i_use_cpu_feature: the other methods should work too.
|
|
||||||
// - GCC >= 6 / Clang / ICX __builtin_cpu_supports("pclmul")
|
|
||||||
//
|
|
||||||
// CPUID decding is needed with MSVC anyway and older GCC. This keeps
|
|
||||||
// the feature checks in the build system simpler too. The nice thing
|
|
||||||
// about __builtin_cpu_supports would be that it generates very short
|
|
||||||
// code as is it only reads a variable set at startup but a few bytes
|
|
||||||
// doesn't matter here.
|
|
||||||
}
|
|
||||||
|
|
||||||
|
|
||||||
typedef uint64_t (*crc64_func_type)(
|
typedef uint64_t (*crc64_func_type)(
|
||||||
const uint8_t *buf, size_t size, uint64_t crc);
|
const uint8_t *buf, size_t size, uint64_t crc);
|
||||||
|
|
||||||
|
|
|
@ -1,9 +1,11 @@
|
||||||
///////////////////////////////////////////////////////////////////////////////
|
///////////////////////////////////////////////////////////////////////////////
|
||||||
//
|
//
|
||||||
/// \file crc_common.h
|
/// \file crc_common.h
|
||||||
/// \brief Some endian-dependent macros for CRC32 and CRC64
|
/// \brief Some functions and macros for CRC32 and CRC64
|
||||||
//
|
//
|
||||||
// Author: Lasse Collin
|
// Authors: Lasse Collin
|
||||||
|
// Ilya Kurdyukov
|
||||||
|
// Hans Jansen
|
||||||
//
|
//
|
||||||
// This file has been put into the public domain.
|
// This file has been put into the public domain.
|
||||||
// You can do whatever you want with this file.
|
// You can do whatever you want with this file.
|
||||||
|
@ -28,3 +30,227 @@
|
||||||
# define S8(x) ((x) >> 8)
|
# define S8(x) ((x) >> 8)
|
||||||
# define S32(x) ((x) >> 32)
|
# define S32(x) ((x) >> 32)
|
||||||
#endif
|
#endif
|
||||||
|
|
||||||
|
|
||||||
|
#undef CRC_GENERIC
|
||||||
|
#undef CRC_CLMUL
|
||||||
|
#undef CRC_USE_GENERIC_FOR_SMALL_INPUTS
|
||||||
|
|
||||||
|
// If CLMUL cannot be used then only the generic slice-by-four is built.
|
||||||
|
#if !defined(HAVE_USABLE_CLMUL)
|
||||||
|
# define CRC_GENERIC 1
|
||||||
|
|
||||||
|
// If CLMUL is allowed unconditionally in the compiler options then the
|
||||||
|
// generic version can be omitted. Note that this doesn't work with MSVC
|
||||||
|
// as I don't know how to detect the features here.
|
||||||
|
//
|
||||||
|
// NOTE: Keep this this in sync with crc32_table.c.
|
||||||
|
#elif (defined(__SSSE3__) && defined(__SSE4_1__) && defined(__PCLMUL__)) \
|
||||||
|
|| (defined(__e2k__) && __iset__ >= 6)
|
||||||
|
# define CRC_CLMUL 1
|
||||||
|
|
||||||
|
// Otherwise build both and detect at runtime which version to use.
|
||||||
|
#else
|
||||||
|
# define CRC_GENERIC 1
|
||||||
|
# define CRC_CLMUL 1
|
||||||
|
|
||||||
|
/*
|
||||||
|
// The generic code is much faster with 1-8-byte inputs and has
|
||||||
|
// similar performance up to 16 bytes at least in microbenchmarks
|
||||||
|
// (it depends on input buffer alignment too). If both versions are
|
||||||
|
// built, this #define will use the generic version for inputs up to
|
||||||
|
// 16 bytes and CLMUL for bigger inputs. It saves a little in code
|
||||||
|
// size since the special cases for 0-16-byte inputs will be omitted
|
||||||
|
// from the CLMUL code.
|
||||||
|
# define CRC_USE_GENERIC_FOR_SMALL_INPUTS 1
|
||||||
|
*/
|
||||||
|
|
||||||
|
# if defined(_MSC_VER)
|
||||||
|
# include <intrin.h>
|
||||||
|
# elif defined(HAVE_CPUID_H)
|
||||||
|
# include <cpuid.h>
|
||||||
|
# endif
|
||||||
|
#endif
|
||||||
|
|
||||||
|
////////////////////////
|
||||||
|
// Detect CPU support //
|
||||||
|
////////////////////////
|
||||||
|
|
||||||
|
#if defined(CRC_GENERIC) && defined(CRC_CLMUL)
|
||||||
|
static inline bool
|
||||||
|
is_clmul_supported(void)
|
||||||
|
{
|
||||||
|
int success = 1;
|
||||||
|
uint32_t r[4]; // eax, ebx, ecx, edx
|
||||||
|
|
||||||
|
#if defined(_MSC_VER)
|
||||||
|
// This needs <intrin.h> with MSVC. ICC has it as a built-in
|
||||||
|
// on all platforms.
|
||||||
|
__cpuid(r, 1);
|
||||||
|
#elif defined(HAVE_CPUID_H)
|
||||||
|
// Compared to just using __asm__ to run CPUID, this also checks
|
||||||
|
// that CPUID is supported and saves and restores ebx as that is
|
||||||
|
// needed with GCC < 5 with position-independent code (PIC).
|
||||||
|
success = __get_cpuid(1, &r[0], &r[1], &r[2], &r[3]);
|
||||||
|
#else
|
||||||
|
// Just a fallback that shouldn't be needed.
|
||||||
|
__asm__("cpuid\n\t"
|
||||||
|
: "=a"(r[0]), "=b"(r[1]), "=c"(r[2]), "=d"(r[3])
|
||||||
|
: "a"(1), "c"(0));
|
||||||
|
#endif
|
||||||
|
|
||||||
|
// Returns true if these are supported:
|
||||||
|
// CLMUL (bit 1 in ecx)
|
||||||
|
// SSSE3 (bit 9 in ecx)
|
||||||
|
// SSE4.1 (bit 19 in ecx)
|
||||||
|
const uint32_t ecx_mask = (1 << 1) | (1 << 9) | (1 << 19);
|
||||||
|
return success && (r[2] & ecx_mask) == ecx_mask;
|
||||||
|
|
||||||
|
// Alternative methods that weren't used:
|
||||||
|
// - ICC's _may_i_use_cpu_feature: the other methods should work too.
|
||||||
|
// - GCC >= 6 / Clang / ICX __builtin_cpu_supports("pclmul")
|
||||||
|
//
|
||||||
|
// CPUID decding is needed with MSVC anyway and older GCC. This keeps
|
||||||
|
// the feature checks in the build system simpler too. The nice thing
|
||||||
|
// about __builtin_cpu_supports would be that it generates very short
|
||||||
|
// code as is it only reads a variable set at startup but a few bytes
|
||||||
|
// doesn't matter here.
|
||||||
|
}
|
||||||
|
#endif
|
||||||
|
|
||||||
|
|
||||||
|
#define MASK_L(in, mask, r) r = _mm_shuffle_epi8(in, mask);
|
||||||
|
#define MASK_H(in, mask, r) \
|
||||||
|
r = _mm_shuffle_epi8(in, _mm_xor_si128(mask, vsign));
|
||||||
|
#define MASK_LH(in, mask, low, high) \
|
||||||
|
MASK_L(in, mask, low) MASK_H(in, mask, high)
|
||||||
|
|
||||||
|
#ifdef CRC_CLMUL
|
||||||
|
|
||||||
|
#include <immintrin.h>
|
||||||
|
|
||||||
|
|
||||||
|
#if (defined(__GNUC__) || defined(__clang__)) && !defined(__EDG__)
|
||||||
|
__attribute__((__target__("ssse3,sse4.1,pclmul")))
|
||||||
|
#endif
|
||||||
|
#if lzma_has_attribute(__no_sanitize_address__)
|
||||||
|
__attribute__((__no_sanitize_address__))
|
||||||
|
#endif
|
||||||
|
static inline void
|
||||||
|
crc_simd_body(const uint8_t *buf, size_t size, __m128i *v0, __m128i *v1,
|
||||||
|
__m128i vfold16, __m128i crc2vec)
|
||||||
|
{
|
||||||
|
#if TUKLIB_GNUC_REQ(4, 6) || defined(__clang__)
|
||||||
|
# pragma GCC diagnostic push
|
||||||
|
# pragma GCC diagnostic ignored "-Wsign-conversion"
|
||||||
|
#endif
|
||||||
|
// Memory addresses A to D and the distances between them:
|
||||||
|
//
|
||||||
|
// A B C D
|
||||||
|
// [skip_start][size][skip_end]
|
||||||
|
// [ size2 ]
|
||||||
|
//
|
||||||
|
// A and D are 16-byte aligned. B and C are 1-byte aligned.
|
||||||
|
// skip_start and skip_end are 0-15 bytes. size is at least 1 byte.
|
||||||
|
//
|
||||||
|
// A = aligned_buf will initially point to this address.
|
||||||
|
// B = The address pointed by the caller-supplied buf.
|
||||||
|
// C = buf + size == aligned_buf + size2
|
||||||
|
// D = buf + size + skip_end == aligned_buf + size2 + skip_end
|
||||||
|
uintptr_t skip_start = (uintptr_t)buf & 15;
|
||||||
|
uintptr_t skip_end = -(uintptr_t)(buf + size) & 15;
|
||||||
|
|
||||||
|
// Create a vector with 8-bit values 0 to 15.
|
||||||
|
// This is used to construct control masks
|
||||||
|
// for _mm_blendv_epi8 and _mm_shuffle_epi8.
|
||||||
|
__m128i vramp = _mm_setr_epi32(
|
||||||
|
0x03020100, 0x07060504, 0x0b0a0908, 0x0f0e0d0c);
|
||||||
|
|
||||||
|
// This is used to inverse the control mask of _mm_shuffle_epi8
|
||||||
|
// so that bytes that wouldn't be picked with the original mask
|
||||||
|
// will be picked and vice versa.
|
||||||
|
__m128i vsign = _mm_set1_epi8(-0x80);
|
||||||
|
|
||||||
|
// Masks to be used with _mm_blendv_epi8 and _mm_shuffle_epi8
|
||||||
|
// The first skip_start or skip_end bytes in the vectors will hav
|
||||||
|
// the high bit (0x80) set. _mm_blendv_epi8 and _mm_shuffle_epi
|
||||||
|
// will produce zeros for these positions. (Bitwise-xor of thes
|
||||||
|
// masks with vsign will produce the opposite behavior.)
|
||||||
|
__m128i mask_start = _mm_sub_epi8(vramp, _mm_set1_epi8(skip_start));
|
||||||
|
__m128i mask_end = _mm_sub_epi8(vramp, _mm_set1_epi8(skip_end));
|
||||||
|
|
||||||
|
// If size2 <= 16 then the whole input fits into a single 16-byte
|
||||||
|
// vector. If size2 > 16 then at least two 16-byte vectors must
|
||||||
|
// be processed. If size2 > 16 && size <= 16 then there is only
|
||||||
|
// one 16-byte vector's worth of input but it is unaligned in memory.
|
||||||
|
//
|
||||||
|
// NOTE: There is no integer overflow here if the arguments
|
||||||
|
// are valid. If this overflowed, buf + size would too.
|
||||||
|
uintptr_t size2 = skip_start + size;
|
||||||
|
const __m128i *aligned_buf = (const __m128i*)((uintptr_t)buf & -16);
|
||||||
|
__m128i v2, v3, vcrc, data0;
|
||||||
|
|
||||||
|
vcrc = crc2vec;
|
||||||
|
|
||||||
|
// Get the first 1-16 bytes into data0. If loading less than 16
|
||||||
|
// bytes, the bytes are loaded to the high bits of the vector and
|
||||||
|
// the least significant positions are filled with zeros.
|
||||||
|
data0 = _mm_load_si128(aligned_buf);
|
||||||
|
data0 = _mm_blendv_epi8(data0, _mm_setzero_si128(), mask_start);
|
||||||
|
aligned_buf++;
|
||||||
|
if (size2 <= 16) {
|
||||||
|
// There are 1-16 bytes of input and it is all
|
||||||
|
// in data0. Copy the input bytes to v3. If there
|
||||||
|
// are fewer than 16 bytes, the low bytes in v3
|
||||||
|
// will be filled with zeros. That is, the input
|
||||||
|
// bytes are stored to the same position as
|
||||||
|
// (part of) initial_crc is in v0.
|
||||||
|
__m128i mask_low = _mm_add_epi8(
|
||||||
|
vramp, _mm_set1_epi8(size - 16));
|
||||||
|
MASK_LH(vcrc, mask_low, *v0, *v1)
|
||||||
|
MASK_L(data0, mask_end, v3)
|
||||||
|
*v0 = _mm_xor_si128(*v0, v3);
|
||||||
|
*v1 = _mm_alignr_epi8(*v1, *v0, 8);
|
||||||
|
} else {
|
||||||
|
__m128i data1 = _mm_load_si128(aligned_buf);
|
||||||
|
if (size <= 16) {
|
||||||
|
// Collect the 2-16 input bytes from data0 and data1
|
||||||
|
// to v2 and v3, and bitwise-xor them with the
|
||||||
|
// low bits of initial_crc in v0. Note that the
|
||||||
|
// the second xor is below this else-block as it
|
||||||
|
// is shared with the other branch.
|
||||||
|
__m128i mask_low = _mm_add_epi8(
|
||||||
|
vramp, _mm_set1_epi8(size - 16));
|
||||||
|
MASK_LH(vcrc, mask_low, *v0, *v1);
|
||||||
|
MASK_H(data0, mask_end, v2)
|
||||||
|
MASK_L(data1, mask_end, v3)
|
||||||
|
*v0 = _mm_xor_si128(*v0, v2);
|
||||||
|
*v0 = _mm_xor_si128(*v0, v3);
|
||||||
|
|
||||||
|
*v1 = _mm_alignr_epi8(*v1, *v0, 8);
|
||||||
|
} else {
|
||||||
|
const __m128i *end = (const __m128i*)(
|
||||||
|
(char*)aligned_buf++ - 16 + size2);
|
||||||
|
MASK_LH(vcrc, mask_start, *v0, *v1)
|
||||||
|
*v0 = _mm_xor_si128(*v0, data0);
|
||||||
|
*v1 = _mm_xor_si128(*v1, data1);
|
||||||
|
while (aligned_buf < end) {
|
||||||
|
*v1 = _mm_xor_si128(*v1, _mm_clmulepi64_si128(*v0, vfold16, 0x00)); \
|
||||||
|
*v0 = _mm_xor_si128(*v1, _mm_clmulepi64_si128(*v0, vfold16, 0x11));
|
||||||
|
*v1 = _mm_load_si128(aligned_buf++);
|
||||||
|
}
|
||||||
|
|
||||||
|
if (aligned_buf != end) {
|
||||||
|
MASK_H(*v0, mask_end, v2)
|
||||||
|
MASK_L(*v0, mask_end, *v0)
|
||||||
|
MASK_L(*v1, mask_end, v3)
|
||||||
|
*v1 = _mm_or_si128(v2, v3);
|
||||||
|
}
|
||||||
|
*v1 = _mm_xor_si128(*v1, _mm_clmulepi64_si128(*v0, vfold16, 0x00));
|
||||||
|
*v0 = _mm_xor_si128(*v1, _mm_clmulepi64_si128(*v0, vfold16, 0x11));
|
||||||
|
|
||||||
|
*v1 = _mm_srli_si128(*v0, 8);
|
||||||
|
}
|
||||||
|
}
|
||||||
|
}
|
||||||
|
#endif
|
||||||
|
|
Loading…
Reference in a new issue