tmk_core/tool/mbed/mbed-sdk/libraries/dsp/cmsis_dsp/FilteringFunctions/arm_fir_init_q7.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_init_q7.c
   9 *
  10 * Description:  Q7 FIR filter 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
  49  * @{
  50  */
  51 /**
  52  * @param[in,out] *S points to an instance of the Q7 FIR filter structure.
  53  * @param[in]     numTaps  Number of filter coefficients in the filter.
  54  * @param[in]     *pCoeffs points to the filter coefficients buffer.
  55  * @param[in]     *pState points to the state buffer.
  56  * @param[in]     blockSize number of samples that are processed per call.
  57  * @return        none
  58  *
  59  * <b>Description:</b>
  60  * \par
  61  * <code>pCoeffs</code> points to the array of filter coefficients stored in time reversed order:
  62  * <pre>
  63  *    {b[numTaps-1], b[numTaps-2], b[N-2], ..., b[1], b[0]}
  64  * </pre>
  65  * \par
  66  * <code>pState</code> points to the array of state variables.
  67  * <code>pState</code> is of length <code>numTaps+blockSize-1</code> samples, where <code>blockSize</code> is the number of input samples processed by each call to <code>arm_fir_q7()</code>.
  68  */
  69
  70 void arm_fir_init_q7(
  71   arm_fir_instance_q7 * S,
  72   uint16_t numTaps,
  73   q7_t * pCoeffs,
  74   q7_t * pState,
  75   uint32_t blockSize)
  76 {
  77
  78   /* Assign filter taps */
  79   S->numTaps = numTaps;
  80
  81   /* Assign coefficient pointer */
  82   S->pCoeffs = pCoeffs;
  83
  84   /* Clear the state buffer.  The size is always (blockSize + numTaps - 1) */
  85   memset(pState, 0, (numTaps + (blockSize - 1u)) * sizeof(q7_t));
  86
  87   /* Assign state pointer */
  88   S->pState = pState;
  89
  90 }
  91
  92 /**
  93  * @} end of FIR group
  94  */