tesseract/src/arch/dotproductavx.cpp
Stefan Weil 61eab60fe3 arch: Reduce number of include files for dot product functions
dotproductavx.h and dotproductsse.h declared only two functions.
Move those declarations to dotproduct.h.

Signed-off-by: Stefan Weil <sw@weilnetz.de>
2019-07-12 23:18:00 +02:00

60 lines
1.9 KiB
C++

///////////////////////////////////////////////////////////////////////
// File: dotproductavx.cpp
// Description: Architecture-specific dot-product function.
// Author: Ray Smith
//
// (C) Copyright 2015, Google Inc.
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
// http://www.apache.org/licenses/LICENSE-2.0
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
///////////////////////////////////////////////////////////////////////
#if !defined(__AVX__)
#error Implementation only for AVX capable architectures
#endif
#include <immintrin.h>
#include <cstdint>
#include "dotproduct.h"
namespace tesseract {
// Computes and returns the dot product of the n-vectors u and v.
// Uses Intel AVX intrinsics to access the SIMD instruction set.
double DotProductAVX(const double* u, const double* v, int n) {
const unsigned quot = n / 8;
const unsigned rem = n % 8;
__m256d t0 = _mm256_setzero_pd();
__m256d t1 = _mm256_setzero_pd();
for (unsigned k = 0; k < quot; k++) {
__m256d f0 = _mm256_loadu_pd(u);
__m256d f1 = _mm256_loadu_pd(v);
f0 = _mm256_mul_pd(f0, f1);
t0 = _mm256_add_pd(t0, f0);
u += 4;
v += 4;
__m256d f2 = _mm256_loadu_pd(u);
__m256d f3 = _mm256_loadu_pd(v);
f2 = _mm256_mul_pd(f2, f3);
t1 = _mm256_add_pd(t1, f2);
u += 4;
v += 4;
}
t0 = _mm256_hadd_pd(t0, t1);
alignas(32) double tmp[4];
_mm256_store_pd(tmp, t0);
double result = tmp[0] + tmp[1] + tmp[2] + tmp[3];
for (unsigned k = 0; k < rem; k++) {
result += *u++ * *v++;
}
return result;
}
} // namespace tesseract.