1 /*
2 * Copyright (c) 2018, Alliance for Open Media. All rights reserved
3 *
4 * This source code is subject to the terms of the BSD 2 Clause License and
5 * the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License
6 * was not distributed with this source code in the LICENSE file, you can
7 * obtain it at www.aomedia.org/license/software. If the Alliance for Open
8 * Media Patent License 1.0 was not distributed with this source code in the
9 * PATENTS file, you can obtain it at www.aomedia.org/license/patent.
10 */
11
12 #include <stdlib.h>
13 #include <memory.h>
14 #include <math.h>
15 #include <assert.h>
16
17 #include <smmintrin.h>
18
19 #include "config/av1_rtcd.h"
20
21 #include "aom_ports/mem.h"
22 #include "aom_ports/system_state.h"
23 #include "av1/encoder/corner_match.h"
24
25 DECLARE_ALIGNED(16, static const uint8_t,
26 byte_mask[16]) = { 255, 255, 255, 255, 255, 255, 255, 255,
27 255, 255, 255, 255, 255, 0, 0, 0 };
28 #if MATCH_SZ != 13
29 #error "Need to change byte_mask in corner_match_sse4.c if MATCH_SZ != 13"
30 #endif
31
32 /* Compute corr(im1, im2) * MATCH_SZ * stddev(im1), where the
33 correlation/standard deviation are taken over MATCH_SZ by MATCH_SZ windows
34 of each image, centered at (x1, y1) and (x2, y2) respectively.
35 */
av1_compute_cross_correlation_sse4_1(unsigned char * im1,int stride1,int x1,int y1,unsigned char * im2,int stride2,int x2,int y2)36 double av1_compute_cross_correlation_sse4_1(unsigned char *im1, int stride1,
37 int x1, int y1, unsigned char *im2,
38 int stride2, int x2, int y2) {
39 int i;
40 // 2 16-bit partial sums in lanes 0, 4 (== 2 32-bit partial sums in lanes 0,
41 // 2)
42 __m128i sum1_vec = _mm_setzero_si128();
43 __m128i sum2_vec = _mm_setzero_si128();
44 // 4 32-bit partial sums of squares
45 __m128i sumsq2_vec = _mm_setzero_si128();
46 __m128i cross_vec = _mm_setzero_si128();
47
48 const __m128i mask = _mm_load_si128((__m128i *)byte_mask);
49 const __m128i zero = _mm_setzero_si128();
50
51 im1 += (y1 - MATCH_SZ_BY2) * stride1 + (x1 - MATCH_SZ_BY2);
52 im2 += (y2 - MATCH_SZ_BY2) * stride2 + (x2 - MATCH_SZ_BY2);
53
54 for (i = 0; i < MATCH_SZ; ++i) {
55 const __m128i v1 =
56 _mm_and_si128(_mm_loadu_si128((__m128i *)&im1[i * stride1]), mask);
57 const __m128i v2 =
58 _mm_and_si128(_mm_loadu_si128((__m128i *)&im2[i * stride2]), mask);
59
60 // Using the 'sad' intrinsic here is a bit faster than adding
61 // v1_l + v1_r and v2_l + v2_r, plus it avoids the need for a 16->32 bit
62 // conversion step later, for a net speedup of ~10%
63 sum1_vec = _mm_add_epi16(sum1_vec, _mm_sad_epu8(v1, zero));
64 sum2_vec = _mm_add_epi16(sum2_vec, _mm_sad_epu8(v2, zero));
65
66 const __m128i v1_l = _mm_cvtepu8_epi16(v1);
67 const __m128i v1_r = _mm_cvtepu8_epi16(_mm_srli_si128(v1, 8));
68 const __m128i v2_l = _mm_cvtepu8_epi16(v2);
69 const __m128i v2_r = _mm_cvtepu8_epi16(_mm_srli_si128(v2, 8));
70
71 sumsq2_vec = _mm_add_epi32(
72 sumsq2_vec,
73 _mm_add_epi32(_mm_madd_epi16(v2_l, v2_l), _mm_madd_epi16(v2_r, v2_r)));
74 cross_vec = _mm_add_epi32(
75 cross_vec,
76 _mm_add_epi32(_mm_madd_epi16(v1_l, v2_l), _mm_madd_epi16(v1_r, v2_r)));
77 }
78
79 // Now we can treat the four registers (sum1_vec, sum2_vec, sumsq2_vec,
80 // cross_vec)
81 // as holding 4 32-bit elements each, which we want to sum horizontally.
82 // We do this by transposing and then summing vertically.
83 __m128i tmp_0 = _mm_unpacklo_epi32(sum1_vec, sum2_vec);
84 __m128i tmp_1 = _mm_unpackhi_epi32(sum1_vec, sum2_vec);
85 __m128i tmp_2 = _mm_unpacklo_epi32(sumsq2_vec, cross_vec);
86 __m128i tmp_3 = _mm_unpackhi_epi32(sumsq2_vec, cross_vec);
87
88 __m128i tmp_4 = _mm_unpacklo_epi64(tmp_0, tmp_2);
89 __m128i tmp_5 = _mm_unpackhi_epi64(tmp_0, tmp_2);
90 __m128i tmp_6 = _mm_unpacklo_epi64(tmp_1, tmp_3);
91 __m128i tmp_7 = _mm_unpackhi_epi64(tmp_1, tmp_3);
92
93 __m128i res =
94 _mm_add_epi32(_mm_add_epi32(tmp_4, tmp_5), _mm_add_epi32(tmp_6, tmp_7));
95
96 int sum1 = _mm_extract_epi32(res, 0);
97 int sum2 = _mm_extract_epi32(res, 1);
98 int sumsq2 = _mm_extract_epi32(res, 2);
99 int cross = _mm_extract_epi32(res, 3);
100
101 int var2 = sumsq2 * MATCH_SZ_SQ - sum2 * sum2;
102 int cov = cross * MATCH_SZ_SQ - sum1 * sum2;
103 aom_clear_system_state();
104 return cov / sqrt((double)var2);
105 }
106