| // Copyright 2015 Google Inc. All rights reserved. |
| // |
| // 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. |
| |
| // SSE3 instrinsics for cumulative sum and conversion to pixels |
| |
| #include <stdint.h> |
| #include <tmmintrin.h> |
| |
| void accumulate_sse(const float *in, uint8_t *out, uint32_t n) { |
| __m128 offset = _mm_setzero_ps(); |
| __m128i mask = _mm_set1_epi32(0x0c080400); |
| __m128 sign_mask = _mm_set1_ps(-0.f); |
| for (uint32_t i = 0; i < n; i += 4) { |
| __m128 x = _mm_load_ps(&in[i]); |
| x = _mm_add_ps(x, _mm_castsi128_ps(_mm_slli_si128(_mm_castps_si128(x), 4))); |
| x = _mm_add_ps(x, _mm_shuffle_ps(_mm_setzero_ps(), x, 0x40)); |
| x = _mm_add_ps(x, offset); |
| __m128 y = _mm_andnot_ps(sign_mask, x); // fabs(x) |
| y = _mm_min_ps(y, _mm_set1_ps(1.0f)); |
| y = _mm_mul_ps(y, _mm_set1_ps(255.0f)); |
| __m128i z = _mm_cvttps_epi32(y); |
| z = _mm_shuffle_epi8(z, mask); |
| _mm_store_ss((float *)&out[i], _mm_castsi128_ps(z)); |
| offset = _mm_shuffle_ps(x, x, _MM_SHUFFLE(3, 3, 3, 3)); |
| } |
| } |
