arm_fir_init_q31.c

00001 /* ----------------------------------------------------------------------  
00002 * Copyright (C) 2010 ARM Limited. All rights reserved.  
00003 *  
00004 * $Date:        29. November 2010  
00005 * $Revision:    V1.0.3  
00006 *  
00007 * Project:      CMSIS DSP Library  
00008 * Title:        arm_fir_init_q31.c  
00009 *  
00010 * Description:  Q31 FIR filter initialization function.  
00011 *  
00012 * Target Processor: Cortex-M4/Cortex-M3
00013 *  
00014 * Version 1.0.3 2010/11/29 
00015 *    Re-organized the CMSIS folders and updated documentation.  
00016 *   
00017 * Version 1.0.2 2010/11/11  
00018 *    Documentation updated.   
00019 *  
00020 * Version 1.0.1 2010/10/05   
00021 *    Production release and review comments incorporated.  
00022 *  
00023 * Version 1.0.0 2010/09/20   
00024 *    Production release and review comments incorporated.  
00025 *  
00026 * Version 0.0.5  2010/04/26   
00027 *    incorporated review comments and updated with latest CMSIS layer  
00028 *  
00029 * Version 0.0.3  2010/03/10   
00030 *    Initial version  
00031 * -------------------------------------------------------------------- */ 
00032  
00033 #include "arm_math.h" 
00034  
00035 /**  
00036  * @ingroup groupFilters  
00037  */ 
00038  
00039 /**  
00040  * @addtogroup FIR  
00041  * @{  
00042  */ 
00043  
00044 /**  
00045  * @details  
00046  *  
00047  * @param[in,out] *S points to an instance of the Q31 FIR filter structure.  
00048  * @param[in]     numTaps  Number of filter coefficients in the filter.  
00049  * @param[in]     *pCoeffs points to the filter coefficients buffer.  
00050  * @param[in]     *pState points to the state buffer.  
00051  * @param[in]     blockSize number of samples that are processed per call.  
00052  * @return        none.  
00053  *  
00054  * <b>Description:</b>  
00055  * \par  
00056  * <code>pCoeffs</code> points to the array of filter coefficients stored in time reversed order:  
00057  * <pre>  
00058  *    {b[numTaps-1], b[numTaps-2], b[N-2], ..., b[1], b[0]}  
00059  * </pre>  
00060  * \par  
00061  * <code>pState</code> points to the array of state variables.  
00062  * <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_q31()</code>.  
00063  */ 
00064  
00065 void arm_fir_init_q31( 
00066   arm_fir_instance_q31 * S, 
00067   uint16_t numTaps, 
00068   q31_t * pCoeffs, 
00069   q31_t * pState, 
00070   uint32_t blockSize) 
00071 { 
00072   /* Assign filter taps */ 
00073   S->numTaps = numTaps; 
00074  
00075   /* Assign coefficient pointer */ 
00076   S->pCoeffs = pCoeffs; 
00077  
00078   /* Clear state buffer and state array size is (blockSize + numTaps - 1) */ 
00079   memset(pState, 0, (blockSize + ((uint32_t) numTaps - 1u)) * sizeof(q31_t)); 
00080  
00081   /* Assign state pointer */ 
00082   S->pState = pState; 
00083  
00084 } 
00085  
00086 /**  
00087  * @} end of FIR group  
00088  */