tmk_core/tool/mbed/mbed-sdk/libraries/dsp/cmsis_dsp/FilteringFunctions/arm_fir_interpolate_init_q31.c

   1 /*-----------------------------------------------------------------------------
   2 * Copyright (C) 2010-2013 ARM Limited. All rights reserved.
   3 *
   4 * $Date:        17. January 2013
   5 * $Revision:    V1.4.1
   6 *
   7 * Project:          CMSIS DSP Library
   8 * Title:        arm_fir_interpolate_init_q31.c
   9 *
  10 * Description:  Q31 FIR interpolator initialization function
  11 *
  12 * Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
  13 *
  14 * Redistribution and use in source and binary forms, with or without
  15 * modification, are permitted provided that the following conditions
  16 * are met:
  17 *   - Redistributions of source code must retain the above copyright
  18 *     notice, this list of conditions and the following disclaimer.
  19 *   - Redistributions in binary form must reproduce the above copyright
  20 *     notice, this list of conditions and the following disclaimer in
  21 *     the documentation and/or other materials provided with the
  22 *     distribution.
  23 *   - Neither the name of ARM LIMITED nor the names of its contributors
  24 *     may be used to endorse or promote products derived from this
  25 *     software without specific prior written permission.
  26 *
  27 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  28 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  29 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  30 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
  31 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  32 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
  33 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  34 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
  35 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  36 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
  37 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  38 * POSSIBILITY OF SUCH DAMAGE.
  39 * ---------------------------------------------------------------------------*/
  40
  41 #include "arm_math.h"
  42
  43 /**
  44  * @ingroup groupFilters
  45  */
  46
  47 /**
  48  * @addtogroup FIR_Interpolate
  49  * @{
  50  */
  51
  52
  53 /**
  54  * @brief  Initialization function for the Q31 FIR interpolator.
  55  * @param[in,out] *S        points to an instance of the Q31 FIR interpolator structure.
  56  * @param[in]     L         upsample factor.
  57  * @param[in]     numTaps   number of filter coefficients in the filter.
  58  * @param[in]     *pCoeffs  points to the filter coefficient buffer.
  59  * @param[in]     *pState   points to the state buffer.
  60  * @param[in]     blockSize number of input samples to process per call.
  61  * @return        The function returns ARM_MATH_SUCCESS if initialization was successful or ARM_MATH_LENGTH_ERROR if
  62  * the filter length <code>numTaps</code> is not a multiple of the interpolation factor <code>L</code>.
  63  *
  64  * <b>Description:</b>
  65  * \par
  66  * <code>pCoeffs</code> points to the array of filter coefficients stored in time reversed order:
  67  * <pre>
  68  *    {b[numTaps-1], b[numTaps-2], b[numTaps-2], ..., b[1], b[0]}
  69  * </pre>
  70  * The length of the filter <code>numTaps</code> must be a multiple of the interpolation factor <code>L</code>.
  71  * \par
  72  * <code>pState</code> points to the array of state variables.
  73  * <code>pState</code> is of length <code>(numTaps/L)+blockSize-1</code> words
  74  * where <code>blockSize</code> is the number of input samples processed by each call to <code>arm_fir_interpolate_q31()</code>.
  75  */
  76
  77 arm_status arm_fir_interpolate_init_q31(
  78   arm_fir_interpolate_instance_q31 * S,
  79   uint8_t L,
  80   uint16_t numTaps,
  81   q31_t * pCoeffs,
  82   q31_t * pState,
  83   uint32_t blockSize)
  84 {
  85   arm_status status;
  86
  87   /* The filter length must be a multiple of the interpolation factor */
  88   if((numTaps % L) != 0u)
  89   {
  90     /* Set status as ARM_MATH_LENGTH_ERROR */
  91     status = ARM_MATH_LENGTH_ERROR;
  92   }
  93   else
  94   {
  95
  96     /* Assign coefficient pointer */
  97     S->pCoeffs = pCoeffs;
  98
  99     /* Assign Interpolation factor */
 100     S->L = L;
 101
 102     /* Assign polyPhaseLength */
 103     S->phaseLength = numTaps / L;
 104
 105     /* Clear state buffer and size of buffer is always phaseLength + blockSize - 1 */
 106     memset(pState, 0,
 107            (blockSize + ((uint32_t) S->phaseLength - 1u)) * sizeof(q31_t));
 108
 109     /* Assign state pointer */
 110     S->pState = pState;
 111
 112     status = ARM_MATH_SUCCESS;
 113   }
 114
 115   return (status);
 116
 117 }
 118
 119  /**
 120   * @} end of FIR_Interpolate group
 121   */