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2 mjames 1
/*
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 * Copyright (C) 2010-2018 Arm Limited or its affiliates. All rights reserved.
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 *
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 * SPDX-License-Identifier: Apache-2.0
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 *
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 * Licensed under the Apache License, Version 2.0 (the License); you may
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 * not use this file except in compliance with the License.
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 * You may obtain a copy of the License at
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 *
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 * www.apache.org/licenses/LICENSE-2.0
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 *
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 * Unless required by applicable law or agreed to in writing, software
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 * distributed under the License is distributed on an AS IS BASIS, WITHOUT
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 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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 * See the License for the specific language governing permissions and
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 * limitations under the License.
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 */
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/* ----------------------------------------------------------------------
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 * Project:      CMSIS NN Library
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 * Title:        arm_nn_activations_q7.c
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 * Description:  Q7 neural network activation function using direct table look-up
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 *
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 * $Date:        17. January 2018
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 * $Revision:    V.1.0.0
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 *
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 * Target Processor:  Cortex-M cores
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 *
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 * -------------------------------------------------------------------- */
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#include "arm_math.h"
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#include "arm_common_tables.h"
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#include "arm_nnfunctions.h"
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/**
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 *  @ingroup groupNN
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 */
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/**
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 * @addtogroup Acti
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 * @{
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 */
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  /**
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   * @brief Q7 neural network activation function using direct table look-up
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   * @param[in,out]   data        pointer to input
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   * @param[in]       size        number of elements
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   * @param[in]       int_width   bit-width of the integer part, assume to be smaller than 3
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   * @param[in]       type        type of activation functions
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   * @return none.
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   *
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   * @details
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   *
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   * This is the direct table look-up approach.
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   *
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   * Assume here the integer part of the fixed-point is <= 3.
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   * More than 3 just not making much sense, makes no difference with
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   * saturation followed by any of these activation functions.
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   */
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void arm_nn_activations_direct_q7(q7_t * data, uint16_t size, uint16_t int_width, arm_nn_activation_type type)
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{
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    uint16_t  i = size;
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    q7_t     *pIn = data;
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    q7_t     *pOut = data;
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    q7_t      in;
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    q7_t      out;
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    uint16_t  shift_size = 3 - int_width;
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    const q7_t *lookup_table;
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    switch (type)
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    {
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    case ARM_SIGMOID:
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        lookup_table = sigmoidTable_q7;
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        break;
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    case ARM_TANH:
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    default:
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        lookup_table = tanhTable_q7;
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        break;
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    }
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    while (i)
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    {
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        in = *pIn++;
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        out = lookup_table[(uint8_t) (in >> shift_size)];
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        *pOut++ = out;
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        i--;
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    }
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}
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/**
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 * @} end of Acti group
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 */