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comparison mupdf-source/thirdparty/tesseract/src/arch/intsimdmatrixsse.cpp @ 2:b50eed0cc0ef upstream

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ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. The directory name has changed: no version number in the expanded directory now.
author Franz Glasner <fzglas.hg@dom66.de>
date Mon, 15 Sep 2025 11:43:07 +0200
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1:1d09e1dec1d9 2:b50eed0cc0ef
1 ///////////////////////////////////////////////////////////////////////
2 // File: intsindmatrixsse.cpp
3 // Description: SSE implementation of 8-bit int SIMD matrix multiply.
4 // Author: Ray Smith
5 //
6 // (C) Copyright 2017, Google Inc.
7 // Licensed under the Apache License, Version 2.0 (the "License");
8 // you may not use this file except in compliance with the License.
9 // You may obtain a copy of the License at
10 // http://www.apache.org/licenses/LICENSE-2.0
11 // Unless required by applicable law or agreed to in writing, software
12 // distributed under the License is distributed on an "AS IS" BASIS,
13 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 // See the License for the specific language governing permissions and
15 // limitations under the License.
16 ///////////////////////////////////////////////////////////////////////
17
18 #if !defined(__SSE4_1__)
19 # if defined(__i686__) || defined(__x86_64__)
20 # error Implementation only for SSE 4.1 capable architectures
21 # endif
22 #else
23
24 # include "intsimdmatrix.h"
25
26 # include <emmintrin.h>
27 # include <smmintrin.h>
28 # include <cstdint>
29
30 namespace tesseract {
31
32 // Computes and returns the dot product of the n-vectors u and v.
33 // Uses Intel SSE intrinsics to access the SIMD instruction set.
34 static int32_t IntDotProductSSE(const int8_t *u, const int8_t *v, int n) {
35 int max_offset = n - 8;
36 int offset = 0;
37 // Accumulate a set of 4 32-bit sums in sum, by loading 8 pairs of 8-bit
38 // values, extending to 16 bit, multiplying to make 32 bit results.
39 int32_t result = 0;
40 if (offset <= max_offset) {
41 offset = 8;
42 __m128i packed1 = _mm_loadl_epi64(reinterpret_cast<const __m128i *>(u));
43 __m128i packed2 = _mm_loadl_epi64(reinterpret_cast<const __m128i *>(v));
44 __m128i sum = _mm_cvtepi8_epi16(packed1);
45 packed2 = _mm_cvtepi8_epi16(packed2);
46 // The magic _mm_add_epi16 is perfect here. It multiplies 8 pairs of 16 bit
47 // ints to make 32 bit results, which are then horizontally added in pairs
48 // to make 4 32 bit results that still fit in a 128 bit register.
49 sum = _mm_madd_epi16(sum, packed2);
50 while (offset <= max_offset) {
51 packed1 = _mm_loadl_epi64(reinterpret_cast<const __m128i *>(u + offset));
52 packed2 = _mm_loadl_epi64(reinterpret_cast<const __m128i *>(v + offset));
53 offset += 8;
54 packed1 = _mm_cvtepi8_epi16(packed1);
55 packed2 = _mm_cvtepi8_epi16(packed2);
56 packed1 = _mm_madd_epi16(packed1, packed2);
57 sum = _mm_add_epi32(sum, packed1);
58 }
59 // Sum the 4 packed 32 bit sums and extract the low result.
60 sum = _mm_hadd_epi32(sum, sum);
61 sum = _mm_hadd_epi32(sum, sum);
62 result = _mm_cvtsi128_si32(sum);
63 }
64 while (offset < n) {
65 result += u[offset] * v[offset];
66 ++offset;
67 }
68 return result;
69 }
70
71 // Computes part of matrix.vector v = Wu. Computes 1 result.
72 static void PartialMatrixDotVector1(const int8_t *wi, const TFloat *scales, const int8_t *u,
73 int num_in, TFloat *v) {
74 TFloat total = IntDotProductSSE(u, wi, num_in);
75 // Add in the bias and correct for integer values.
76 *v = (total + wi[num_in] * INT8_MAX) * *scales;
77 }
78
79 static void matrixDotVector(int dim1, int dim2, const int8_t *wi, const TFloat *scales,
80 const int8_t *u, TFloat *v) {
81 const int num_out = dim1;
82 const int num_in = dim2 - 1;
83 int output = 0;
84
85 for (; output < num_out; output++) {
86 PartialMatrixDotVector1(wi, scales, u, num_in, v);
87 wi += dim2;
88 scales++;
89 v++;
90 }
91 }
92
93 const IntSimdMatrix IntSimdMatrix::intSimdMatrixSSE = {
94 matrixDotVector,
95 // Number of 32 bit outputs held in each register.
96 1,
97 // Maximum number of registers that we will use to hold outputs.
98 1,
99 // Number of 8 bit inputs in the inputs register.
100 1,
101 // Number of inputs in each weight group.
102 1
103 };
104
105 } // namespace tesseract.
106
107 #endif