Diff: FilteringFunctions/arm_fir_interpolate_init_q31.c

Revision:

0:3d9c67d97d6f

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/FilteringFunctions/arm_fir_interpolate_init_q31.c	Mon Jul 28 15:03:15 2014 +0000
@@ -0,0 +1,121 @@
+/*-----------------------------------------------------------------------------    
+* Copyright (C) 2010-2014 ARM Limited. All rights reserved.    
+*    
+* $Date:        12. March 2014
+* $Revision: 	V1.4.3
+*    
+* Project: 	    CMSIS DSP Library    
+* Title:        arm_fir_interpolate_init_q31.c    
+*    
+* Description:  Q31 FIR interpolator initialization function    
+*    
+* Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
+*  
+* Redistribution and use in source and binary forms, with or without 
+* modification, are permitted provided that the following conditions
+* are met:
+*   - Redistributions of source code must retain the above copyright
+*     notice, this list of conditions and the following disclaimer.
+*   - Redistributions in binary form must reproduce the above copyright
+*     notice, this list of conditions and the following disclaimer in
+*     the documentation and/or other materials provided with the 
+*     distribution.
+*   - Neither the name of ARM LIMITED nor the names of its contributors
+*     may be used to endorse or promote products derived from this
+*     software without specific prior written permission.
+*
+* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 
+* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+* POSSIBILITY OF SUCH DAMAGE.   
+* ---------------------------------------------------------------------------*/
+
+#include "arm_math.h"
+
+/**    
+ * @ingroup groupFilters    
+ */
+
+/**    
+ * @addtogroup FIR_Interpolate    
+ * @{    
+ */
+
+
+/**    
+ * @brief  Initialization function for the Q31 FIR interpolator.    
+ * @param[in,out] *S        points to an instance of the Q31 FIR interpolator structure.    
+ * @param[in]     L         upsample factor.    
+ * @param[in]     numTaps   number of filter coefficients in the filter.    
+ * @param[in]     *pCoeffs  points to the filter coefficient buffer.    
+ * @param[in]     *pState   points to the state buffer.    
+ * @param[in]     blockSize number of input samples to process per call.    
+ * @return        The function returns ARM_MATH_SUCCESS if initialization was successful or ARM_MATH_LENGTH_ERROR if    
+ * the filter length <code>numTaps</code> is not a multiple of the interpolation factor <code>L</code>.    
+ *    
+ * <b>Description:</b>    
+ * \par    
+ * <code>pCoeffs</code> points to the array of filter coefficients stored in time reversed order:    
+ * <pre>    
+ *    {b[numTaps-1], b[numTaps-2], b[numTaps-2], ..., b[1], b[0]}    
+ * </pre>    
+ * The length of the filter <code>numTaps</code> must be a multiple of the interpolation factor <code>L</code>.    
+ * \par    
+ * <code>pState</code> points to the array of state variables.    
+ * <code>pState</code> is of length <code>(numTaps/L)+blockSize-1</code> words    
+ * where <code>blockSize</code> is the number of input samples processed by each call to <code>arm_fir_interpolate_q31()</code>.    
+ */
+
+arm_status arm_fir_interpolate_init_q31(
+  arm_fir_interpolate_instance_q31 * S,
+  uint8_t L,
+  uint16_t numTaps,
+  q31_t * pCoeffs,
+  q31_t * pState,
+  uint32_t blockSize)
+{
+  arm_status status;
+
+  /* The filter length must be a multiple of the interpolation factor */
+  if((numTaps % L) != 0u)
+  {
+    /* Set status as ARM_MATH_LENGTH_ERROR */
+    status = ARM_MATH_LENGTH_ERROR;
+  }
+  else
+  {
+
+    /* Assign coefficient pointer */
+    S->pCoeffs = pCoeffs;
+
+    /* Assign Interpolation factor */
+    S->L = L;
+
+    /* Assign polyPhaseLength */
+    S->phaseLength = numTaps / L;
+
+    /* Clear state buffer and size of buffer is always phaseLength + blockSize - 1 */
+    memset(pState, 0,
+           (blockSize + ((uint32_t) S->phaseLength - 1u)) * sizeof(q31_t));
+
+    /* Assign state pointer */
+    S->pState = pState;
+
+    status = ARM_MATH_SUCCESS;
+  }
+
+  return (status);
+
+}
+
+ /**    
+  * @} end of FIR_Interpolate group    
+  */