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      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 (at) anholt.net>
     25  *    Matt Turner <mattst88 (at) 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 }
     89