tmk_core/tool/mbed/mbed-sdk/libraries/dsp/cmsis_dsp/FilteringFunctions/arm_lms_norm_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_lms_norm_init_q31.c
   9 *
  10 * Description:  Q31 NLMS 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 #include "arm_common_tables.h"
  43
  44 /**
  45  * @addtogroup LMS_NORM
  46  * @{
  47  */
  48
  49   /**
  50    * @brief Initialization function for Q31 normalized LMS filter.
  51    * @param[in] *S points to an instance of the Q31 normalized LMS filter structure.
  52    * @param[in] numTaps  number of filter coefficients.
  53    * @param[in] *pCoeffs points to coefficient buffer.
  54    * @param[in] *pState points to state buffer.
  55    * @param[in] mu step size that controls filter coefficient updates.
  56    * @param[in] blockSize number of samples to process.
  57    * @param[in] postShift bit shift applied to coefficients.
  58    * @return none.
  59  *
  60  * <b>Description:</b>
  61  * \par
  62  * <code>pCoeffs</code> points to the array of filter coefficients stored in time reversed order:
  63  * <pre>
  64  *    {b[numTaps-1], b[numTaps-2], b[N-2], ..., b[1], b[0]}
  65  * </pre>
  66  * The initial filter coefficients serve as a starting point for the adaptive filter.
  67  * <code>pState</code> points to an array of length <code>numTaps+blockSize-1</code> samples,
  68  * where <code>blockSize</code> is the number of input samples processed by each call to <code>arm_lms_norm_q31()</code>.
  69  */
  70
  71 void arm_lms_norm_init_q31(
  72   arm_lms_norm_instance_q31 * S,
  73   uint16_t numTaps,
  74   q31_t * pCoeffs,
  75   q31_t * pState,
  76   q31_t mu,
  77   uint32_t blockSize,
  78   uint8_t postShift)
  79 {
  80   /* Assign filter taps */
  81   S->numTaps = numTaps;
  82
  83   /* Assign coefficient pointer */
  84   S->pCoeffs = pCoeffs;
  85
  86   /* Clear state buffer and size is always blockSize + numTaps - 1  */
  87   memset(pState, 0, (numTaps + (blockSize - 1u)) * sizeof(q31_t));
  88
  89   /* Assign post Shift value applied to coefficients */
  90   S->postShift = postShift;
  91
  92   /* Assign state pointer */
  93   S->pState = pState;
  94
  95   /* Assign Step size value */
  96   S->mu = mu;
  97
  98   /* Initialize reciprocal pointer table */
  99   S->recipTable = (q31_t *) armRecipTableQ31;
 100
 101   /* Initialise Energy to zero */
 102   S->energy = 0;
 103
 104   /* Initialise x0 to zero */
 105   S->x0 = 0;
 106
 107 }
 108
 109 /**
 110  * @} end of LMS_NORM group
 111  */