|  | /* | 
|  | * Copyright (c) 2020, Alliance for Open Media. All rights reserved | 
|  | * | 
|  | * This source code is subject to the terms of the BSD 2 Clause License and | 
|  | * the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License | 
|  | * was not distributed with this source code in the LICENSE file, you can | 
|  | * obtain it at www.aomedia.org/license/software. If the Alliance for Open | 
|  | * Media Patent License 1.0 was not distributed with this source code in the | 
|  | * PATENTS file, you can obtain it at www.aomedia.org/license/patent. | 
|  | */ | 
|  |  | 
|  | #include <assert.h> | 
|  | #include <immintrin.h> | 
|  | #include <math.h> | 
|  |  | 
|  | #include "aom_dsp/aom_dsp_common.h" | 
|  | #include "av1/common/av1_common_int.h" | 
|  | #include "av1/encoder/cnn.h" | 
|  |  | 
|  | // This mask rearranges source pixels in the order shown below. | 
|  | // shuffle_src_layer0[0][8]: applied on source pixels 0 to 7. | 
|  | // shuffle_src_layer0[1][8]: applied on source pixels 7 to 14. | 
|  | // This shuffling is needed to process 3 5x5 blocks which need | 
|  | // source pixels in the following order. | 
|  | // 1st 5x5 block: source pixels needed are 0 to 4, | 
|  | // 2nd 5x5 block: source pixels needed are 4 to 8, | 
|  | // 3rd 5x5 block: source pixels needed are 8 to 12. | 
|  | // Source pixels are loaded like mentioned below. | 
|  | // load_src0 : 0, 1, 2, 3, 4, 5, 6, 7 | 
|  | // load_src1 : 7, 8, 9, 10, 11, 12, 13, 14 | 
|  | // After applying masks, source bytes will be in the order: | 
|  | // load_src0 : 0, 1, 2, 3, 4, 4, 5, 6 | 
|  | //             consists 5 pixels needed for 1st 5x5 block and | 
|  | //             first 3 pixels needed for 2nd 5x5 block. | 
|  | // load_src1 : 7, 8, 8, 9, 10, 11, 12, x | 
|  | //             consists last 2 pixels needed for 2nd 5x5 block and | 
|  | //             5 pixels needed for 3rd 5x5 block. | 
|  | DECLARE_ALIGNED(32, static const uint32_t, | 
|  | shuffle_src_layer0[2][8]) = { { 0, 1, 2, 3, 4, 4, 5, 6 }, | 
|  | { 0, 1, 1, 2, 3, 4, 5, 0 } }; | 
|  |  | 
|  | // This mask rearrange the weights to match shuffled source pixels order. | 
|  | DECLARE_ALIGNED(32, static const uint32_t, | 
|  | shuffle_weight_layer0[2][8]) = { { 0, 1, 2, 3, 4, 0, 1, 2 }, | 
|  | { 3, 4, 0, 1, 2, 3, 4, 0 } }; | 
|  |  | 
|  | // Shuffle mask used to rearrange weights corresponding to layer 1 and layer 2. | 
|  | // For layer 1 and layer 2, convolution happens at 2x2 as filter_width and | 
|  | // filter_height are equal to 2. So rearranging the weights in the | 
|  | // order shown below to match source pixels. Basically this mask replicates | 
|  | // the weights across the width of 2. | 
|  | DECLARE_ALIGNED(32, static const uint32_t, | 
|  | shuffle_weight_layer_1_and_2[2][8]) = { | 
|  | { 0, 1, 0, 1, 0, 1, 0, 1 }, { 2, 3, 2, 3, 2, 3, 2, 3 } | 
|  | }; | 
|  |  | 
|  | // After the stages of multiplication and accumulation, the output values | 
|  | // in the register will be jumbled. In order to store register into | 
|  | // output buffer in a proper way, the following mask is applied on output | 
|  | // register. | 
|  | DECLARE_ALIGNED(32, static const uint32_t, | 
|  | shuffle_output_layer_1_and_2[8]) = { 0, 1, 4, 5, 2, 3, 6, 7 }; | 
|  |  | 
|  | // Load weights needed for layer 0 (for 5x5 block processing), | 
|  | // and fill the registers appropriately to match source pixel mapping. | 
|  | static INLINE void prepare_weights_for_5x5_convolve( | 
|  | const float *layer_config_weights, int off, float weight[5][8], | 
|  | const int cstep, __m256 *shuffle_weight, const __m256i weight_mask_0, | 
|  | const __m256i weight_mask_1) { | 
|  | for (int row = 0; row < 5; ++row) { | 
|  | for (int col = 0; col < 5; ++col) { | 
|  | weight[row][col] = layer_config_weights[off]; | 
|  | off += cstep; | 
|  | } | 
|  | } | 
|  | shuffle_weight[0] = _mm256_loadu_ps(weight[0]); | 
|  | shuffle_weight[1] = _mm256_loadu_ps(weight[1]); | 
|  | shuffle_weight[2] = _mm256_loadu_ps(weight[2]); | 
|  | shuffle_weight[3] = _mm256_loadu_ps(weight[3]); | 
|  | shuffle_weight[4] = _mm256_loadu_ps(weight[4]); | 
|  |  | 
|  | shuffle_weight[0] = | 
|  | _mm256_permutevar8x32_ps(shuffle_weight[0], weight_mask_0); | 
|  | shuffle_weight[1] = | 
|  | _mm256_permutevar8x32_ps(shuffle_weight[1], weight_mask_0); | 
|  | shuffle_weight[2] = | 
|  | _mm256_permutevar8x32_ps(shuffle_weight[2], weight_mask_0); | 
|  | shuffle_weight[3] = | 
|  | _mm256_permutevar8x32_ps(shuffle_weight[3], weight_mask_0); | 
|  | shuffle_weight[4] = | 
|  | _mm256_permutevar8x32_ps(shuffle_weight[4], weight_mask_0); | 
|  | shuffle_weight[5] = | 
|  | _mm256_permutevar8x32_ps(shuffle_weight[0], weight_mask_1); | 
|  | shuffle_weight[6] = | 
|  | _mm256_permutevar8x32_ps(shuffle_weight[1], weight_mask_1); | 
|  | shuffle_weight[7] = | 
|  | _mm256_permutevar8x32_ps(shuffle_weight[2], weight_mask_1); | 
|  | shuffle_weight[8] = | 
|  | _mm256_permutevar8x32_ps(shuffle_weight[3], weight_mask_1); | 
|  | shuffle_weight[9] = | 
|  | _mm256_permutevar8x32_ps(shuffle_weight[4], weight_mask_1); | 
|  | } | 
|  |  | 
|  | // For each row, loads source pixels 0 to 7(load_src_0), 7 to 14(load_src_1) and | 
|  | // arranges them appropriately to process 3 blocks. | 
|  | #define PERFORM_CONVOLVE_FOR_3_5X5_BLOCKS()                            \ | 
|  | {                                                                    \ | 
|  | for (int row = 0; row < 5; row++) {                                \ | 
|  | load_src_0 = _mm256_loadu_ps(input_ptr);                         \ | 
|  | load_src_1 = _mm256_loadu_ps(input_ptr + 7);                     \ | 
|  | load_src_0 = _mm256_permutevar8x32_ps(load_src_0, block0_1);     \ | 
|  | load_src_1 = _mm256_permutevar8x32_ps(load_src_1, block1_2);     \ | 
|  | load_src_0 = _mm256_mul_ps(load_src_0, shuffle_weight[0 + row]); \ | 
|  | load_src_1 = _mm256_mul_ps(load_src_1, shuffle_weight[5 + row]); \ | 
|  | accum_src_0 = _mm256_add_ps(load_src_0, accum_src_0);            \ | 
|  | accum_src_1 = _mm256_add_ps(load_src_1, accum_src_1);            \ | 
|  | input_ptr += in_stride;                                          \ | 
|  | }                                                                  \ | 
|  | } | 
|  |  | 
|  | // Load masks needed for shuffling of output and weights. | 
|  | static INLINE void load_shuffle_masks_for_2x2_convolve(__m256i *output_mask, | 
|  | __m256i *weight_mask) { | 
|  | // Load shuffle buffer needed to sort the output. | 
|  | *output_mask = | 
|  | _mm256_load_si256((const __m256i *)shuffle_output_layer_1_and_2); | 
|  |  | 
|  | // Load shuffle buffers needed for weight. | 
|  | weight_mask[0] = | 
|  | _mm256_load_si256((const __m256i *)shuffle_weight_layer_1_and_2[0]); | 
|  | weight_mask[1] = | 
|  | _mm256_load_si256((const __m256i *)shuffle_weight_layer_1_and_2[1]); | 
|  | } | 
|  |  | 
|  | // Load weights needed for layer 1 and 2 (for 2x2 block processing), | 
|  | // and fill the registers appropriately to match source pixel mapping. | 
|  | static INLINE void prepare_weights_for_2x2_convolve( | 
|  | const float *layer_config_weights, int off, const int cstep, | 
|  | __m256 *shuffle_weight, __m256i *weight_mask) { | 
|  | // Weights needed for 2x2 block. | 
|  | float weight[4] = { 0 }; | 
|  | for (int i = 0; i < 4; ++i) { | 
|  | weight[i] = layer_config_weights[off]; | 
|  | off += cstep; | 
|  | } | 
|  |  | 
|  | const __m256 weight_vec = _mm256_castps128_ps256(_mm_loadu_ps(weight)); | 
|  | shuffle_weight[0] = _mm256_permutevar8x32_ps(weight_vec, weight_mask[0]); | 
|  | shuffle_weight[1] = _mm256_permutevar8x32_ps(weight_vec, weight_mask[1]); | 
|  | } | 
|  |  | 
|  | // Do convolution of one 5x5 block. | 
|  | #define PERFORM_CONVOLVE_FOR_1_5X5_BLOCK(w, accum0, in_stride)           \ | 
|  | {                                                                      \ | 
|  | __m128 load_src[5];                                                  \ | 
|  | load_src[0] = _mm_loadu_ps(input_ptr);                               \ | 
|  | last_column_sum += input_ptr[4] * weight[0][4];                      \ | 
|  | input_ptr += in_stride;                                              \ | 
|  | load_src[1] = _mm_loadu_ps(input_ptr);                               \ | 
|  | last_column_sum += input_ptr[4] * weight[1][4];                      \ | 
|  | input_ptr += in_stride;                                              \ | 
|  | load_src[2] = _mm_loadu_ps(input_ptr);                               \ | 
|  | last_column_sum += input_ptr[4] * weight[2][4];                      \ | 
|  | input_ptr += in_stride;                                              \ | 
|  | load_src[3] = _mm_loadu_ps(input_ptr);                               \ | 
|  | last_column_sum += input_ptr[4] * weight[3][4];                      \ | 
|  | input_ptr += in_stride;                                              \ | 
|  | load_src[4] = _mm_loadu_ps(input_ptr);                               \ | 
|  | last_column_sum += input_ptr[4] * weight[4][4];                      \ | 
|  | \ | 
|  | load_src[0] = _mm_mul_ps(load_src[0], _mm256_castps256_ps128(w[0])); \ | 
|  | load_src[1] = _mm_mul_ps(load_src[1], _mm256_castps256_ps128(w[1])); \ | 
|  | load_src[2] = _mm_mul_ps(load_src[2], _mm256_castps256_ps128(w[2])); \ | 
|  | load_src[3] = _mm_mul_ps(load_src[3], _mm256_castps256_ps128(w[3])); \ | 
|  | load_src[4] = _mm_mul_ps(load_src[4], _mm256_castps256_ps128(w[4])); \ | 
|  | \ | 
|  | accum0 = _mm_add_ps(load_src[0], accum0);                            \ | 
|  | load_src[1] = _mm_add_ps(load_src[1], load_src[2]);                  \ | 
|  | load_src[3] = _mm_add_ps(load_src[3], load_src[4]);                  \ | 
|  | load_src[1] = _mm_add_ps(load_src[1], load_src[3]);                  \ | 
|  | accum0 = _mm_add_ps(accum0, load_src[1]);                            \ | 
|  | } | 
|  |  | 
|  | // Do convolution on 8 horizontal 2x2 blocks. | 
|  | static INLINE void perform_convolve_for_8h_2x2_blocks( | 
|  | const float *input_ptr, int in_stride, __m256 *weight, __m256 *out_accum, | 
|  | __m256i shuffle_output_mask) { | 
|  | __m256 load_src[4]; | 
|  | // Load input into source registers. | 
|  | load_src[0] = _mm256_loadu_ps(input_ptr); | 
|  | load_src[1] = _mm256_loadu_ps(input_ptr + 8); | 
|  | load_src[2] = _mm256_loadu_ps(input_ptr + in_stride); | 
|  | load_src[3] = _mm256_loadu_ps(input_ptr + in_stride + 8); | 
|  |  | 
|  | // Multiply the loaded input with corresponding weights. | 
|  | load_src[0] = _mm256_mul_ps(load_src[0], weight[0]); | 
|  | load_src[1] = _mm256_mul_ps(load_src[1], weight[0]); | 
|  | load_src[2] = _mm256_mul_ps(load_src[2], weight[1]); | 
|  | load_src[3] = _mm256_mul_ps(load_src[3], weight[1]); | 
|  |  | 
|  | // Accumulate across 2x2 blocks. | 
|  | load_src[0] = _mm256_add_ps(load_src[0], load_src[2]); | 
|  | load_src[1] = _mm256_add_ps(load_src[1], load_src[3]); | 
|  | load_src[0] = _mm256_hadd_ps(load_src[0], load_src[1]); | 
|  |  | 
|  | // Sort the output in order to store into output buffer. | 
|  | load_src[0] = _mm256_permutevar8x32_ps(load_src[0], shuffle_output_mask); | 
|  | *out_accum = _mm256_add_ps(*out_accum, load_src[0]); | 
|  | } | 
|  |  | 
|  | // Do convolution on 8 (4 horizontal x 2 vertical) 2x2 blocks. | 
|  | static INLINE void perform_convolve_for_4hx2v_2x2_blocks( | 
|  | const float *input_ptr, int in_stride, __m256 *weight, __m256 *out_accum, | 
|  | __m256i shuffle_output_mask) { | 
|  | __m256 load_src[4]; | 
|  | // Load input into source registers. | 
|  | load_src[0] = _mm256_loadu_ps(input_ptr); | 
|  | load_src[1] = _mm256_loadu_ps(input_ptr + in_stride); | 
|  | load_src[2] = _mm256_loadu_ps(input_ptr + (in_stride * 2)); | 
|  | load_src[3] = _mm256_loadu_ps(input_ptr + (in_stride * 3)); | 
|  |  | 
|  | // Multiply the loaded input with corresponding weights. | 
|  | load_src[0] = _mm256_mul_ps(load_src[0], weight[0]); | 
|  | load_src[1] = _mm256_mul_ps(load_src[1], weight[1]); | 
|  | load_src[2] = _mm256_mul_ps(load_src[2], weight[0]); | 
|  | load_src[3] = _mm256_mul_ps(load_src[3], weight[1]); | 
|  |  | 
|  | // Accumulate across 2x2 blocks. | 
|  | load_src[0] = _mm256_add_ps(load_src[0], load_src[1]); | 
|  | load_src[2] = _mm256_add_ps(load_src[2], load_src[3]); | 
|  | load_src[0] = _mm256_hadd_ps(load_src[0], load_src[2]); | 
|  |  | 
|  | // Sort the output in order to store into output buffer. | 
|  | load_src[0] = _mm256_permutevar8x32_ps(load_src[0], shuffle_output_mask); | 
|  | *out_accum = _mm256_add_ps(*out_accum, load_src[0]); | 
|  | } | 
|  |  | 
|  | // AVX2 variant of av1_cnn_convolve_no_maxpool_padding_valid_c(), when | 
|  | // filter_width and filter_height are equal to 5. | 
|  | // CNN convolve parsing is based on av1_intra_mode_cnn_partition_cnn_config. | 
|  | // Based on the configuration set for each layer, the current encoder | 
|  | // always chooses the case of no_maxpool_padding_valid. | 
|  | // And also for layer 0 convolution happens at 5x5 level as the | 
|  | // filter_width and filter_height are set as 5. | 
|  | static void cnn_convolve_no_maxpool_padding_valid_5x5_avx2( | 
|  | const float **input, int in_width, int in_height, int in_stride, | 
|  | const CNN_LAYER_CONFIG *const layer_config, float **output, int out_stride, | 
|  | int start_idx, const int cstep, const int channel_step) { | 
|  | const int kFilterWidth = 5; | 
|  | const int kFilterHeight = 5; | 
|  | const int kSkipWidth = 4; | 
|  | const int kSkipHeight = 4; | 
|  | assert(layer_config->filter_width == kFilterWidth && | 
|  | layer_config->filter_height == kFilterHeight); | 
|  | assert(layer_config->skip_width == kSkipWidth && | 
|  | layer_config->skip_height == kSkipHeight); | 
|  |  | 
|  | // Load shuffle buffers needed for source. | 
|  | const __m256i block0_1 = | 
|  | _mm256_load_si256((const __m256i *)shuffle_src_layer0[0]); | 
|  | const __m256i block1_2 = | 
|  | _mm256_load_si256((const __m256i *)shuffle_src_layer0[1]); | 
|  |  | 
|  | // Load shuffle buffers needed for weight. | 
|  | const __m256i weight_mask_0 = | 
|  | _mm256_load_si256((const __m256i *)shuffle_weight_layer0[0]); | 
|  | const __m256i weight_mask_1 = | 
|  | _mm256_load_si256((const __m256i *)shuffle_weight_layer0[1]); | 
|  |  | 
|  | // Width needs to be moved to go to next iteration of processing 3 5x5 blocks. | 
|  | const int kSkipWidthForNextIter = kSkipWidth * 3; | 
|  |  | 
|  | // Minimum width required to process 3 5x5 blocks at a time. | 
|  | // min width (for processing 3 5x5 block) = 2*skip_width + filter_width | 
|  | // Here, skip_width specifies how much width we should move while processing | 
|  | // next block convolution and filter_width specifies for how many pixels | 
|  | // filter needs to be applied. | 
|  | const int kMinWidthFor3_5x5Blocks = (kSkipWidth * 2) + kFilterWidth; | 
|  | for (int i = start_idx; i < layer_config->out_channels; i += channel_step) { | 
|  | const float out_ch_bias = layer_config->bias[i]; | 
|  | for (int k = 0; k < layer_config->in_channels; ++k) { | 
|  | __m256 shuffle_weight[10]; | 
|  |  | 
|  | // Weights needed are 5x5, for SIMD purpose made this array as 5x8. | 
|  | float weight[5][8] = { { 0 } }; | 
|  | int off = k * layer_config->out_channels + i; | 
|  |  | 
|  | // In layer 0, the convolution process happens at 5x5. | 
|  | // The weights needed for 5x5 block are same across the in-channels, | 
|  | // which is why the load of weights happens once for each in-channel. | 
|  | prepare_weights_for_5x5_convolve(layer_config->weights, off, weight, | 
|  | cstep, shuffle_weight, weight_mask_0, | 
|  | weight_mask_1); | 
|  |  | 
|  | for (int h = 0, u = 0; h < in_height - kFilterHeight + 1; | 
|  | h += kSkipHeight, ++u) { | 
|  | const int out_h = u * out_stride; | 
|  | int v = 0; | 
|  | int w = 0; | 
|  | int rem_width = in_width; | 
|  | // Processing 3 5x5 blocks at a time, if sufficient width is present. | 
|  | while (rem_width >= kMinWidthFor3_5x5Blocks) { | 
|  | __m256 load_src_0, load_src_1; | 
|  | __m256 accum_src_0 = _mm256_setzero_ps(); | 
|  | __m256 accum_src_1 = _mm256_setzero_ps(); | 
|  | const float *input_ptr = &input[k][h * in_stride + w]; | 
|  | PERFORM_CONVOLVE_FOR_3_5X5_BLOCKS(); | 
|  |  | 
|  | // Accumulate across column. | 
|  | __m256 accum = _mm256_hadd_ps(accum_src_0, accum_src_1); | 
|  | __m128 tmp_reg_0 = _mm256_extractf128_ps(accum_src_0, 1); | 
|  | __m128 tmp_reg_1 = _mm256_extractf128_ps(accum_src_1, 1); | 
|  |  | 
|  | __m128 accum_l = _mm256_castps256_ps128(accum); | 
|  | __m128 accum_h = _mm256_extractf128_ps(accum, 1); | 
|  |  | 
|  | __m128 tmp_reg_2 = _mm_add_ps(accum_l, tmp_reg_0); | 
|  | __m128 tmp_reg_3 = _mm_add_ps(tmp_reg_0, accum_h); | 
|  | __m128 tmp_reg_4 = _mm_add_ps(tmp_reg_1, accum_h); | 
|  |  | 
|  | // 1st 5x5 block output. | 
|  | output[i][out_h + v] = | 
|  | out_ch_bias + _mm_cvtss_f32(tmp_reg_2) + | 
|  | _mm_cvtss_f32(_mm_shuffle_ps(accum_l, accum_l, 1)); | 
|  |  | 
|  | // 2nd 5x5 block output. | 
|  | output[i][out_h + v + 1] = | 
|  | out_ch_bias + | 
|  | _mm_cvtss_f32(_mm_shuffle_ps(tmp_reg_3, tmp_reg_3, 1)) + | 
|  | _mm_cvtss_f32(_mm_shuffle_ps(accum_l, accum_l, 2)); | 
|  |  | 
|  | // 3rd 5x5 block output. | 
|  | output[i][out_h + v + 2] = | 
|  | out_ch_bias + | 
|  | _mm_cvtss_f32(_mm_shuffle_ps(tmp_reg_4, tmp_reg_4, 2)) + | 
|  | _mm_cvtss_f32(_mm_shuffle_ps(accum_l, accum_l, 3)); | 
|  |  | 
|  | v += 3; | 
|  | w += kSkipWidthForNextIter; | 
|  | rem_width -= kSkipWidthForNextIter; | 
|  | } | 
|  |  | 
|  | // Process remaining blocks as single 5x5 block at a time. | 
|  | while (rem_width >= kFilterWidth) { | 
|  | float last_column_sum = 0; | 
|  | __m128 accum = _mm_setzero_ps(); | 
|  | const float *input_ptr = &input[k][h * in_stride + w]; | 
|  | PERFORM_CONVOLVE_FOR_1_5X5_BLOCK(shuffle_weight, accum, in_stride); | 
|  |  | 
|  | // Accumulate across column. | 
|  | accum = _mm_hadd_ps(accum, accum); | 
|  | output[i][out_h + v] = out_ch_bias + last_column_sum + | 
|  | _mm_cvtss_f32(accum) + | 
|  | _mm_cvtss_f32(_mm_shuffle_ps(accum, accum, 1)); | 
|  |  | 
|  | v += 1; | 
|  | w += kSkipWidth; | 
|  | rem_width -= kSkipWidth; | 
|  | } | 
|  | } | 
|  | } | 
|  | } | 
|  | } | 
|  |  | 
|  | // AVX2 implementation for layer 1. | 
|  | static INLINE void cnn_convolve_no_maxpool_padding_valid_layer1_avx2( | 
|  | const float **input, int in_stride, | 
|  | const CNN_LAYER_CONFIG *const layer_config, float **output, int out_stride, | 
|  | int start_idx, const int cstep, const int channel_step) { | 
|  | __m256i weight_mask[2]; | 
|  | __m256i shuffle_output_mask; | 
|  | load_shuffle_masks_for_2x2_convolve(&shuffle_output_mask, weight_mask); | 
|  |  | 
|  | const int kInHeight = 16; | 
|  | const int kFilterHeight = 2; | 
|  | const int kSkipHeight = 2; | 
|  | for (int i = start_idx; i < layer_config->out_channels; i += channel_step) { | 
|  | __m256 bias_reg = _mm256_set1_ps(layer_config->bias[i]); | 
|  | // out_accum registers are used to store the 2x2 convolve outputs | 
|  | // (calculated over input block size), which are accumulated across the | 
|  | // in_channels. As per the design, each iteration of for loop processes 8 | 
|  | // (horizontal) 2x2 blocks and stores in corresponding out_accum register | 
|  | // (as input size is 16x16, a total of 64 2x2 blocks are present and 8 | 
|  | // out_accum registers are enough to store the outputs). | 
|  | // Hence for loops corresponding to 'j' and 'h', below, run over the number | 
|  | // of out_accum registers. | 
|  | __m256 out_accum[8]; | 
|  | for (int j = 0; j < 8; ++j) out_accum[j] = bias_reg; | 
|  | for (int k = 0; k < layer_config->in_channels; ++k) { | 
|  | __m256 shuffle_weight[2]; | 
|  | int off = k * layer_config->out_channels + i; | 
|  | // In layer 1, the convolution process happens at 2x2. | 
|  | // The weights needed for 2x2 block are same across the in-channels, | 
|  | // which is why the load of weights happens once for each in-channel. | 
|  | prepare_weights_for_2x2_convolve(layer_config->weights, off, cstep, | 
|  | shuffle_weight, weight_mask); | 
|  |  | 
|  | for (int h = 0, u = 0; h < kInHeight - kFilterHeight + 1; | 
|  | h += kSkipHeight, ++u) { | 
|  | const float *input_ptr = &input[k][h * in_stride]; | 
|  | perform_convolve_for_8h_2x2_blocks(input_ptr, in_stride, shuffle_weight, | 
|  | &out_accum[u], shuffle_output_mask); | 
|  | } | 
|  | } | 
|  | // Store output of layer 1. | 
|  | for (int j = 0; j < 8; ++j) { | 
|  | _mm256_storeu_ps(&output[i][j * out_stride], out_accum[j]); | 
|  | } | 
|  | } | 
|  | } | 
|  |  | 
|  | // AVX2 implementation for layer 2. | 
|  | static INLINE void cnn_convolve_no_maxpool_padding_valid_layer2_avx2( | 
|  | const float **input, int in_stride, | 
|  | const CNN_LAYER_CONFIG *const layer_config, float **output, int out_stride, | 
|  | int start_idx, const int cstep, const int channel_step) { | 
|  | __m256i weight_mask[2]; | 
|  | __m256i shuffle_output_mask; | 
|  | load_shuffle_masks_for_2x2_convolve(&shuffle_output_mask, weight_mask); | 
|  |  | 
|  | const int kInHeight = 8; | 
|  | const int kFilterHeight = 2; | 
|  | const int kSkipHeight = 2; | 
|  | for (int i = start_idx; i < layer_config->out_channels; i += channel_step) { | 
|  | __m256 bias_reg = _mm256_set1_ps(layer_config->bias[i]); | 
|  | // out_accum registers are used to store the 2x2 convolve outputs | 
|  | // (calculated over input block size), which are accumulated across the | 
|  | // in_channels. As per the design, each iteration of for loop processes 8 | 
|  | // (4 horizontal x 2 vertical) 2x2 blocks and stores in corresponding | 
|  | // out_accum register (as input size is 8x8, a total of 16 2x2 blocks are | 
|  | // present and 2 out_accum registers are enough to store the outputs). | 
|  | // Hence for loops corresponding to 'j' and 'h', below, run over the number | 
|  | // of out_accum registers. | 
|  | __m256 out_accum[2]; | 
|  |  | 
|  | // Height needs to be moved to go to next iteration of processing | 
|  | // while processing 2 2x2 blocks vertically. | 
|  | const int kSkipHeightForNextIter = kSkipHeight * 2; | 
|  | for (int j = 0; j < 2; ++j) out_accum[j] = bias_reg; | 
|  | for (int k = 0; k < layer_config->in_channels; ++k) { | 
|  | __m256 shuffle_weight[2]; | 
|  | int off = k * layer_config->out_channels + i; | 
|  | // In layer 2, the convolution process happens at 2x2. | 
|  | // The weights needed for 2x2 block are same across the in-channels, | 
|  | // which is why the load of weights happens once for each in-channel. | 
|  | prepare_weights_for_2x2_convolve(layer_config->weights, off, cstep, | 
|  | shuffle_weight, weight_mask); | 
|  |  | 
|  | for (int h = 0, u = 0; h < kInHeight - kFilterHeight + 1; | 
|  | h += kSkipHeightForNextIter, ++u) { | 
|  | const float *input_ptr = &input[k][h * in_stride]; | 
|  | perform_convolve_for_4hx2v_2x2_blocks(input_ptr, in_stride, | 
|  | shuffle_weight, &out_accum[u], | 
|  | shuffle_output_mask); | 
|  | } | 
|  | } | 
|  | // Store output of layer 2. | 
|  | for (int j = 0; j < 2; ++j) { | 
|  | _mm256_storeu_ps(&output[i][j * out_stride * 2], out_accum[j]); | 
|  | } | 
|  | } | 
|  | } | 
|  |  | 
|  | // AVX2 variant of av1_cnn_convolve_no_maxpool_padding_valid_c(), when | 
|  | // filter_width and filter_height are equal to 2. | 
|  | // As per the layer config set by av1_intra_mode_cnn_partition_cnn_config, | 
|  | // the filter_width and filter_height are equal to 2 for layer >= 1. So | 
|  | // convolution happens at 2x2 for layer >= 1. | 
|  | void cnn_convolve_no_maxpool_padding_valid_2x2_avx2( | 
|  | const float **input, int in_width, int in_height, int in_stride, | 
|  | const CNN_LAYER_CONFIG *const layer_config, float **output, int out_stride, | 
|  | int start_idx, const int cstep, const int channel_step) { | 
|  | assert(layer_config->filter_width == 2 && layer_config->filter_height == 2); | 
|  | assert(layer_config->skip_width == 2 && layer_config->skip_height == 2); | 
|  |  | 
|  | if (in_width == 16 && in_height == 16) { | 
|  | // This case of in_width and in_height equal to 16 corresponds to layer 1. | 
|  | // The output size of this layer is 8x8. | 
|  | cnn_convolve_no_maxpool_padding_valid_layer1_avx2( | 
|  | input, in_stride, layer_config, output, out_stride, start_idx, cstep, | 
|  | channel_step); | 
|  | } else if (in_width == 8 && in_height == 8) { | 
|  | // This case of in_width and in_height equal to 8 corresponds to layer 2. | 
|  | // The output size of this layer is 4x4. | 
|  | cnn_convolve_no_maxpool_padding_valid_layer2_avx2( | 
|  | input, in_stride, layer_config, output, out_stride, start_idx, cstep, | 
|  | channel_step); | 
|  | } else { | 
|  | // For layer equal to 3 and 4, the input is of size 4x4 and 2x2 | 
|  | // respectively. Implementing SIMD for these cases might not be optimal, | 
|  | // which is why we call C path for layer >= 3. | 
|  | av1_cnn_convolve_no_maxpool_padding_valid_c( | 
|  | input, in_width, in_height, in_stride, layer_config, output, out_stride, | 
|  | start_idx, cstep, channel_step); | 
|  | } | 
|  | } | 
|  |  | 
|  | // AVX2 variant of av1_cnn_convolve_no_maxpool_padding_valid_c(). | 
|  | // As per the current encoder, av1_cnn_convolve function gets called for | 
|  | // block size equal to 64x64. av1_cnn_convolve() uses layer config values | 
|  | // set by av1_intra_mode_cnn_partition_cnn_config. The following are a few | 
|  | // details related to each layer's config parameters. | 
|  | // Layer_Number in_size out_size filter_wd filter_ht skip_wd skip_ht | 
|  | //     0         64x64    16x16      5         5         4       4 | 
|  | //     1         16x16    8x8        2         2         2       2 | 
|  | //     2         8x8      4x4        2         2         2       2 | 
|  | //     3         4x4      2x2        2         2         2       2 | 
|  | //     4         2x2      1x1        2         2         2       2 | 
|  | // Here, | 
|  | // filter_wd = filter_width and filter_ht = filter_height, | 
|  | // skip_wd = skip_width and skip_ht = skip_height. | 
|  | void av1_cnn_convolve_no_maxpool_padding_valid_avx2( | 
|  | const float **input, int in_width, int in_height, int in_stride, | 
|  | const CNN_LAYER_CONFIG *layer_config, float **output, int out_stride, | 
|  | int start_idx, int cstep, int channel_step) { | 
|  | if (layer_config->filter_width == 5 && layer_config->filter_height == 5 && | 
|  | layer_config->skip_width == 4 && layer_config->skip_height == 4) { | 
|  | cnn_convolve_no_maxpool_padding_valid_5x5_avx2( | 
|  | input, in_width, in_height, in_stride, layer_config, output, out_stride, | 
|  | start_idx, cstep, channel_step); | 
|  | } else if (layer_config->filter_width == 2 && | 
|  | layer_config->filter_height == 2 && | 
|  | layer_config->skip_width == 2 && layer_config->skip_height == 2) { | 
|  | cnn_convolve_no_maxpool_padding_valid_2x2_avx2( | 
|  | input, in_width, in_height, in_stride, layer_config, output, out_stride, | 
|  | start_idx, cstep, channel_step); | 
|  | } else { | 
|  | av1_cnn_convolve_no_maxpool_padding_valid_c( | 
|  | input, in_width, in_height, in_stride, layer_config, output, out_stride, | 
|  | start_idx, cstep, channel_step); | 
|  | } | 
|  | } |