src/mesa/main/streaming-load-memcpy.c

   1 /*
   2  * Copyright © 2013 Intel Corporation
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a
   5  * copy of this software and associated documentation files (the "Software"),
   6  * to deal in the Software without restriction, including without limitation
   7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   8  * and/or sell copies of the Software, and to permit persons to whom the
   9  * Software is furnished to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice (including the next
  12  * paragraph) shall be included in all copies or substantial portions of the
  13  * Software.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  18  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  19  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  20  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  21  * IN THE SOFTWARE.
  22  *
  23  * Authors:
  24  *    Eric Anholt <eric@anholt.net>
  25  *    Matt Turner <mattst88@gmail.com>
  26  *
  27  */
  28
  29 #include "main/macros.h"
  30 #include "main/streaming-load-memcpy.h"
  31 #include <smmintrin.h>
  32
  33 /* Copies memory from src to dst, using SSE 4.1's MOVNTDQA to get streaming
  34  * read performance from uncached memory.
  35  */
  36 void
  37 _mesa_streaming_load_memcpy(void *restrict dst, void *restrict src, size_t len)
  38 {
  39    char *restrict d = dst;
  40    char *restrict s = src;
  41
  42    /* If dst and src are not co-aligned, fallback to memcpy(). */
  43    if (((uintptr_t)d & 15) != ((uintptr_t)s & 15)) {
  44       memcpy(d, s, len);
  45       return;
  46    }
  47
  48    /* memcpy() the misaligned header. At the end of this if block, <d> and <s>
  49     * are aligned to a 16-byte boundary or <len> == 0.
  50     */
  51    if ((uintptr_t)d & 15) {
  52       uintptr_t bytes_before_alignment_boundary = 16 - ((uintptr_t)d & 15);
  53       assert(bytes_before_alignment_boundary < 16);
  54
  55       memcpy(d, s, MIN2(bytes_before_alignment_boundary, len));
  56
  57       d = (char *)ALIGN((uintptr_t)d, 16);
  58       s = (char *)ALIGN((uintptr_t)s, 16);
  59       len -= MIN2(bytes_before_alignment_boundary, len);
  60    }
  61
  62    if (len >= 64)
  63       _mm_mfence();
  64
  65    while (len >= 64) {
  66       __m128i *dst_cacheline = (__m128i *)d;
  67       __m128i *src_cacheline = (__m128i *)s;
  68
  69       __m128i temp1 = _mm_stream_load_si128(src_cacheline + 0);
  70       __m128i temp2 = _mm_stream_load_si128(src_cacheline + 1);
  71       __m128i temp3 = _mm_stream_load_si128(src_cacheline + 2);
  72       __m128i temp4 = _mm_stream_load_si128(src_cacheline + 3);
  73
  74       _mm_store_si128(dst_cacheline + 0, temp1);
  75       _mm_store_si128(dst_cacheline + 1, temp2);
  76       _mm_store_si128(dst_cacheline + 2, temp3);
  77       _mm_store_si128(dst_cacheline + 3, temp4);
  78
  79       d += 64;
  80       s += 64;
  81       len -= 64;
  82    }
  83
  84    /* memcpy() the tail. */
  85    if (len) {
  86       memcpy(d, s, len);
  87    }
  88 }