| /* |
| * Copyright (C) 2010-2018 Arm Limited or its affiliates. All rights reserved. |
| * |
| * SPDX-License-Identifier: Apache-2.0 |
| * |
| * 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 |
| * |
| * 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. |
| */ |
| |
| /* ---------------------------------------------------------------------- |
| * Project: CMSIS NN Library |
| * Title: arm_nn_activations_q15.c |
| * Description: Q15 neural network activation function using direct table look-up |
| * |
| * $Date: 17. January 2018 |
| * $Revision: V.1.0.0 |
| * |
| * Target Processor: Cortex-M cores |
| * |
| * -------------------------------------------------------------------- */ |
| |
| #include "arm_math.h" |
| #include "arm_common_tables.h" |
| #include "arm_nnfunctions.h" |
| |
| /** |
| * @ingroup groupNN |
| */ |
| |
| /** |
| * @addtogroup Acti |
| * @{ |
| */ |
| |
| /** |
| * @brief Q15 neural network activation function using direct table look-up |
| * @param[in,out] data pointer to input |
| * @param[in] size number of elements |
| * @param[in] int_width bit-width of the integer part, assume to be smaller than 3 |
| * @param[in] type type of activation functions |
| * @return none. |
| * |
| * @details |
| * |
| * This is the direct table look-up approach. |
| * |
| * Assume here the integer part of the fixed-point is <= 3. |
| * More than 3 just not making much sense, makes no difference with |
| * saturation followed by any of these activation functions. |
| */ |
| |
| void arm_nn_activations_direct_q15(q15_t * data, uint16_t size, uint16_t int_width, arm_nn_activation_type type) |
| { |
| uint16_t i = size; |
| q15_t *pIn = data; |
| q15_t *pOut = data; |
| uint16_t shift_size = 8 + 3 - int_width; |
| uint32_t bit_mask = 0x7FF >> int_width; |
| uint32_t full_frac = bit_mask + 1; |
| const q15_t *lookup_table; |
| |
| switch (type) |
| { |
| case ARM_SIGMOID: |
| lookup_table = sigmoidTable_q15; |
| break; |
| case ARM_TANH: |
| default: |
| lookup_table = tanhTable_q15; |
| break; |
| } |
| |
| while (i) |
| { |
| q15_t out; |
| q15_t in = *pIn++; |
| q15_t frac = (uint32_t) in & bit_mask; |
| q15_t value = lookup_table[__USAT(in >> shift_size, 8)]; |
| q15_t value2 = lookup_table[__USAT(1 + (in >> shift_size), 8)]; |
| |
| /* doing the interpolation here for better accuracy */ |
| out = ((q31_t) (full_frac - frac) * value + (q31_t) value2 * frac) >> shift_size; |
| |
| *pOut++ = out; |
| i--; |
| } |
| |
| } |
| |
| /** |
| * @} end of Acti group |
| */ |