Diff: cmsis_dsp/FilteringFunctions/arm_fir_decimate_init_f32.c

Revision:

1:fdd22bb7aa52

Child:

2:da51fb522205

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/cmsis_dsp/FilteringFunctions/arm_fir_decimate_init_f32.c	Wed Nov 28 12:30:09 2012 +0000
@@ -0,0 +1,112 @@
+/*-----------------------------------------------------------------------------    
+* Copyright (C) 2010 ARM Limited. All rights reserved.    
+*    
+* $Date:        15. February 2012  
+* $Revision:     V1.1.0  
+*    
+* Project:         CMSIS DSP Library    
+* Title:        arm_fir_decimate_init_f32.c    
+*    
+* Description:  Floating-point FIR Decimator 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_decimate    
+ * @{    
+ */
+
+/**    
+ * @brief  Initialization function for the floating-point FIR decimator.    
+ * @param[in,out] *S points to an instance of the floating-point FIR decimator structure.    
+ * @param[in] numTaps  number of coefficients in the filter.    
+ * @param[in] M  decimation factor.    
+ * @param[in] *pCoeffs points to the filter coefficients.    
+ * @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    
+ * <code>blockSize</code> is not a multiple of <code>M</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[N-2], ..., b[1], b[0]}    
+ * </pre>    
+ * \par    
+ * <code>pState</code> points to the array of state variables.    
+ * <code>pState</code> is of length <code>numTaps+blockSize-1</code> words where <code>blockSize</code> is the number of input samples passed to <code>arm_fir_decimate_f32()</code>.    
+ * <code>M</code> is the decimation factor.    
+ */
+
+arm_status arm_fir_decimate_init_f32(
+  arm_fir_decimate_instance_f32 * S,
+  uint16_t numTaps,
+  uint8_t M,
+  float32_t * pCoeffs,
+  float32_t * pState,
+  uint32_t blockSize)
+{
+  arm_status status;
+
+  /* The size of the input block must be a multiple of the decimation factor */
+  if((blockSize % M) != 0u)
+  {
+    /* Set status as ARM_MATH_LENGTH_ERROR */
+    status = ARM_MATH_LENGTH_ERROR;
+  }
+  else
+  {
+    /* Assign filter taps */
+    S->numTaps = numTaps;
+
+    /* Assign coefficient pointer */
+    S->pCoeffs = pCoeffs;
+
+    /* Clear state buffer and size is always (blockSize + numTaps - 1) */
+    memset(pState, 0, (numTaps + (blockSize - 1u)) * sizeof(float32_t));
+
+    /* Assign state pointer */
+    S->pState = pState;
+
+    /* Assign Decimation Factor */
+    S->M = M;
+
+    status = ARM_MATH_SUCCESS;
+  }
+
+  return (status);
+
+}
+
+/**    
+ * @} end of FIR_decimate group    
+ */