memcpy_avx2.h

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/*
 * Copyright (c) 2016 Cisco and/or its affiliates.
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at:
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
/*-
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 *   Copyright(c) 2010-2014 Intel Corporation. All rights reserved.
 *   All rights reserved.
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 *   modification, are permitted provided that the following conditions
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 */

#ifndef included_clib_memcpy_avx2_h
#define included_clib_memcpy_avx2_h

#include <stdint.h>
#include <x86intrin.h>

static inline void
clib_mov16 (u8 * dst, const u8 * src)
{
  __m128i xmm0;

  xmm0 = _mm_loadu_si128 ((const __m128i *) src);
  _mm_storeu_si128 ((__m128i *) dst, xmm0);
}

static inline void
clib_mov32 (u8 * dst, const u8 * src)
{
  __m256i ymm0;

  ymm0 = _mm256_loadu_si256 ((const __m256i *) src);
  _mm256_storeu_si256 ((__m256i *) dst, ymm0);
}

static inline void
clib_mov64 (u8 * dst, const u8 * src)
{
  clib_mov32 ((u8 *) dst + 0 * 32, (const u8 *) src + 0 * 32);
  clib_mov32 ((u8 *) dst + 1 * 32, (const u8 *) src + 1 * 32);
}

static inline void
clib_mov128 (u8 * dst, const u8 * src)
{
  clib_mov64 ((u8 *) dst + 0 * 64, (const u8 *) src + 0 * 64);
  clib_mov64 ((u8 *) dst + 1 * 64, (const u8 *) src + 1 * 64);
}

static inline void
clib_mov128blocks (u8 * dst, const u8 * src, size_t n)
{
  __m256i ymm0, ymm1, ymm2, ymm3;

  while (n >= 128)
    {
      ymm0 =
        _mm256_loadu_si256 ((const __m256i *) ((const u8 *) src + 0 * 32));
      n -= 128;
      ymm1 =
        _mm256_loadu_si256 ((const __m256i *) ((const u8 *) src + 1 * 32));
      ymm2 =
        _mm256_loadu_si256 ((const __m256i *) ((const u8 *) src + 2 * 32));
      ymm3 =
        _mm256_loadu_si256 ((const __m256i *) ((const u8 *) src + 3 * 32));
      src = (const u8 *) src + 128;
      _mm256_storeu_si256 ((__m256i *) ((u8 *) dst + 0 * 32), ymm0);
      _mm256_storeu_si256 ((__m256i *) ((u8 *) dst + 1 * 32), ymm1);
      _mm256_storeu_si256 ((__m256i *) ((u8 *) dst + 2 * 32), ymm2);
      _mm256_storeu_si256 ((__m256i *) ((u8 *) dst + 3 * 32), ymm3);
      dst = (u8 *) dst + 128;
    }
}

static inline void *
clib_memcpy_fast (void *dst, const void *src, size_t n)
{
  uword dstu = (uword) dst;
  uword srcu = (uword) src;
  void *ret = dst;
  size_t dstofss;
  size_t bits;

  /**
   * Copy less than 16 bytes
   */
  if (n < 16)
    {
      if (n & 0x01)
        {
          *(u8 *) dstu = *(const u8 *) srcu;
          srcu = (uword) ((const u8 *) srcu + 1);
          dstu = (uword) ((u8 *) dstu + 1);
        }
      if (n & 0x02)
        {
          *(u16 *) dstu = *(const u16 *) srcu;
          srcu = (uword) ((const u16 *) srcu + 1);
          dstu = (uword) ((u16 *) dstu + 1);
        }
      if (n & 0x04)
        {
          *(u32 *) dstu = *(const u32 *) srcu;
          srcu = (uword) ((const u32 *) srcu + 1);
          dstu = (uword) ((u32 *) dstu + 1);
        }
      if (n & 0x08)
        {
          *(u64 *) dstu = *(const u64 *) srcu;
        }
      return ret;
    }

  /**
    * Fast way when copy size doesn't exceed 512 bytes
    */
  if (n <= 32)
    {
      clib_mov16 ((u8 *) dst, (const u8 *) src);
      clib_mov16 ((u8 *) dst - 16 + n, (const u8 *) src - 16 + n);
      return ret;
    }
  if (n <= 48)
    {
      clib_mov16 ((u8 *) dst, (const u8 *) src);
      clib_mov16 ((u8 *) dst + 16, (const u8 *) src + 16);
      clib_mov16 ((u8 *) dst - 16 + n, (const u8 *) src - 16 + n);
      return ret;
    }
  if (n <= 64)
    {
      clib_mov32 ((u8 *) dst, (const u8 *) src);
      clib_mov32 ((u8 *) dst - 32 + n, (const u8 *) src - 32 + n);
      return ret;
    }
  if (n <= 256)
    {
      if (n >= 128)
        {
          n -= 128;
          clib_mov128 ((u8 *) dst, (const u8 *) src);
          src = (const u8 *) src + 128;
          dst = (u8 *) dst + 128;
        }
    COPY_BLOCK_128_BACK31:
      if (n >= 64)
        {
          n -= 64;
          clib_mov64 ((u8 *) dst, (const u8 *) src);
          src = (const u8 *) src + 64;
          dst = (u8 *) dst + 64;
        }
      if (n > 32)
        {
          clib_mov32 ((u8 *) dst, (const u8 *) src);
          clib_mov32 ((u8 *) dst - 32 + n, (const u8 *) src - 32 + n);
          return ret;
        }
      if (n > 0)
        {
          clib_mov32 ((u8 *) dst - 32 + n, (const u8 *) src - 32 + n);
        }
      return ret;
    }

    /**
      * Make store aligned when copy size exceeds 256 bytes
      */
  dstofss = (uword) dst & 0x1F;
  if (dstofss > 0)
    {
      dstofss = 32 - dstofss;
      n -= dstofss;
      clib_mov32 ((u8 *) dst, (const u8 *) src);
      src = (const u8 *) src + dstofss;
      dst = (u8 *) dst + dstofss;
    }

  /**
    * Copy 128-byte blocks.
    */
  clib_mov128blocks ((u8 *) dst, (const u8 *) src, n);
  bits = n;
  n = n & 127;
  bits -= n;
  src = (const u8 *) src + bits;
  dst = (u8 *) dst + bits;

  /**
   * Copy whatever left
   */
  goto COPY_BLOCK_128_BACK31;
}


#endif /* included_clib_memcpy_avx2_h */


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