arm_iir_lattice_init_q31.c

00001 /*-----------------------------------------------------------------------------    
00002 * Copyright (C) 2010-2014 ARM Limited. All rights reserved.    
00003 *    
00004 * $Date:        19. March 2015
00005 * $Revision:    V.1.4.5
00006 *    
00007 * Project:      CMSIS DSP Library    
00008 * Title:        arm_iir_lattice_init_q31.c    
00009 *    
00010 * Description:  Initialization function for the Q31 IIR lattice filter.    
00011 *    
00012 * Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
00013 *  
00014 * Redistribution and use in source and binary forms, with or without 
00015 * modification, are permitted provided that the following conditions
00016 * are met:
00017 *   - Redistributions of source code must retain the above copyright
00018 *     notice, this list of conditions and the following disclaimer.
00019 *   - Redistributions in binary form must reproduce the above copyright
00020 *     notice, this list of conditions and the following disclaimer in
00021 *     the documentation and/or other materials provided with the 
00022 *     distribution.
00023 *   - Neither the name of ARM LIMITED nor the names of its contributors
00024 *     may be used to endorse or promote products derived from this
00025 *     software without specific prior written permission.
00026 *
00027 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
00028 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
00029 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
00030 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 
00031 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
00032 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
00033 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
00034 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
00035 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
00036 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
00037 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
00038 * POSSIBILITY OF SUCH DAMAGE.  
00039 * ---------------------------------------------------------------------------*/
00040 
00041 #include "arm_math.h"
00042 
00043 /**    
00044  * @ingroup groupFilters    
00045  */
00046 
00047 /**    
00048  * @addtogroup IIR_Lattice    
00049  * @{    
00050  */
00051 
00052   /**    
00053    * @brief Initialization function for the Q31 IIR lattice filter.    
00054    * @param[in] *S points to an instance of the Q31 IIR lattice structure.    
00055    * @param[in] numStages number of stages in the filter.    
00056    * @param[in] *pkCoeffs points to the reflection coefficient buffer.  The array is of length numStages.    
00057    * @param[in] *pvCoeffs points to the ladder coefficient buffer.  The array is of length numStages+1.    
00058    * @param[in] *pState points to the state buffer.  The array is of length numStages+blockSize.    
00059    * @param[in] blockSize number of samples to process.    
00060    * @return none.    
00061    */
00062 
00063 void arm_iir_lattice_init_q31(
00064   arm_iir_lattice_instance_q31 * S,
00065   uint16_t numStages,
00066   q31_t * pkCoeffs,
00067   q31_t * pvCoeffs,
00068   q31_t * pState,
00069   uint32_t blockSize)
00070 {
00071   /* Assign filter taps */
00072   S->numStages = numStages;
00073 
00074   /* Assign reflection coefficient pointer */
00075   S->pkCoeffs = pkCoeffs;
00076 
00077   /* Assign ladder coefficient pointer */
00078   S->pvCoeffs = pvCoeffs;
00079 
00080   /* Clear state buffer and size is always blockSize + numStages */
00081   memset(pState, 0, (numStages + blockSize) * sizeof(q31_t));
00082 
00083   /* Assign state pointer */
00084   S->pState = pState;
00085 
00086 
00087 }
00088 
00089 /**    
00090  * @} end of IIR_Lattice group    
00091  */