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
32 void
_mesa_uint_array_min_max(const unsigned * ui_indices,unsigned * min_index,unsigned * max_index,const unsigned count)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