1/*
2 * Copyright © 2014 Timothy Arceri
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 * Author:
24 *    Timothy Arceri <t_arceri@yahoo.com.au>
25 *
26 */
27
28#include "main/sse_minmax.h"
29#include <smmintrin.h>
30#include <stdint.h>
31
32void
33_mesa_uint_array_min_max(const unsigned *ui_indices, unsigned *min_index,
34                         unsigned *max_index, const unsigned count)
35{
36   unsigned max_ui = 0;
37   unsigned min_ui = ~0U;
38   unsigned i = 0;
39   unsigned aligned_count = count;
40
41   /* handle the first few values without SSE until the pointer is aligned */
42   while (((uintptr_t)ui_indices & 15) && aligned_count) {
43      if (*ui_indices > max_ui)
44         max_ui = *ui_indices;
45      if (*ui_indices < min_ui)
46         min_ui = *ui_indices;
47
48      aligned_count--;
49      ui_indices++;
50   }
51
52   /* TODO: The actual threshold for SSE begin useful may be higher than 8.
53    * Some careful microbenchmarks and measurement are required to
54    * find the actual tipping point.
55    */
56   if (aligned_count >= 8) {
57      unsigned max_arr[4] __attribute__ ((aligned (16)));
58      unsigned min_arr[4] __attribute__ ((aligned (16)));
59      unsigned vec_count;
60      __m128i max_ui4 = _mm_setzero_si128();
61      __m128i min_ui4 = _mm_set1_epi32(~0U);
62      __m128i ui_indices4;
63      __m128i *ui_indices_ptr;
64
65      vec_count = aligned_count & ~0x3;
66      ui_indices_ptr = (__m128i *)ui_indices;
67      for (i = 0; i < vec_count / 4; i++) {
68         ui_indices4 = _mm_load_si128(&ui_indices_ptr[i]);
69         max_ui4 = _mm_max_epu32(ui_indices4, max_ui4);
70         min_ui4 = _mm_min_epu32(ui_indices4, min_ui4);
71      }
72
73      _mm_store_si128((__m128i *)max_arr, max_ui4);
74      _mm_store_si128((__m128i *)min_arr, min_ui4);
75
76      for (i = 0; i < 4; i++) {
77         if (max_arr[i] > max_ui)
78            max_ui = max_arr[i];
79         if (min_arr[i] < min_ui)
80            min_ui = min_arr[i];
81      }
82      i = vec_count;
83   }
84
85   for (; i < aligned_count; i++) {
86      if (ui_indices[i] > max_ui)
87         max_ui = ui_indices[i];
88      if (ui_indices[i] < min_ui)
89         min_ui = ui_indices[i];
90   }
91
92   *min_index = min_ui;
93   *max_index = max_ui;
94}
95