Diff: cmsis_dsp/FilteringFunctions/arm_fir_interpolate_init_q15.c

Revision:

1:fdd22bb7aa52

Child:

2:da51fb522205

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/cmsis_dsp/FilteringFunctions/arm_fir_interpolate_init_q15.c	Wed Nov 28 12:30:09 2012 +0000
@@ -0,0 +1,115 @@
+/*-----------------------------------------------------------------------------    
+* Copyright (C) 2010 ARM Limited. All rights reserved.    
+*    
+* $Date:        15. February 2012  
+* $Revision:     V1.1.0  
+*    
+* Project:         CMSIS DSP Library    
+* Title:        arm_fir_interpolate_init_q15.c    
+*    
+* Description:  Q15 FIR interpolator initialization function    
+*    
+* Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
+*  
+* Version 1.1.0 2012/02/15 
+*    Updated with more optimizations, bug fixes and minor API changes.  
+*   
+* Version 1.0.10 2011/7/15  
+*    Big Endian support added and Merged M0 and M3/M4 Source code.   
+*    
+* Version 1.0.3 2010/11/29   
+*    Re-organized the CMSIS folders and updated documentation.    
+*     
+* Version 1.0.2 2010/11/11    
+*    Documentation updated.     
+*    
+* Version 1.0.1 2010/10/05     
+*    Production release and review comments incorporated.    
+*    
+* Version 1.0.0 2010/09/20     
+*    Production release and review comments incorporated    
+*    
+* Version 0.0.7  2010/06/10     
+*    Misra-C changes done    
+* ---------------------------------------------------------------------------*/
+
+#include "arm_math.h"
+
+/**    
+ * @ingroup groupFilters    
+ */
+
+/**    
+ * @addtogroup FIR_Interpolate    
+ * @{    
+ */
+
+/**    
+ * @brief  Initialization function for the Q15 FIR interpolator.    
+ * @param[in,out] *S        points to an instance of the Q15 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_q15()</code>.    
+ */
+
+arm_status arm_fir_interpolate_init_q15(
+  arm_fir_interpolate_instance_q15 * S,
+  uint8_t L,
+  uint16_t numTaps,
+  q15_t * pCoeffs,
+  q15_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(q15_t));
+
+    /* Assign state pointer */
+    S->pState = pState;
+
+    status = ARM_MATH_SUCCESS;
+  }
+
+  return (status);
+
+}
+
+ /**    
+  * @} end of FIR_Interpolate group    
+  */