Diff: cmsis_dsp/FilteringFunctions/arm_fir_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_init_q15.c	Wed Nov 28 12:30:09 2012 +0000
@@ -0,0 +1,152 @@
+/* ----------------------------------------------------------------------    
+* Copyright (C) 2010 ARM Limited. All rights reserved.    
+*    
+* $Date:        15. February 2012  
+* $Revision:     V1.1.0  
+*    
+* Project:         CMSIS DSP Library    
+* Title:        arm_fir_init_q15.c    
+*    
+* Description:  Q15 FIR filter 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 0.0.5  2010/04/26     
+*      incorporated review comments and updated with latest CMSIS layer    
+*    
+* Version 0.0.3  2010/03/10     
+*    Initial version    
+* ------------------------------------------------------------------- */
+
+#include "arm_math.h"
+
+/**    
+ * @ingroup groupFilters    
+ */
+
+/**    
+ * @addtogroup FIR    
+ * @{    
+ */
+
+/**    
+ * @param[in,out]  *S points to an instance of the Q15 FIR filter structure.    
+ * @param[in]        numTaps  Number of filter coefficients in the filter. Must be even and greater than or equal to 4.    
+ * @param[in]      *pCoeffs points to the filter coefficients buffer.    
+ * @param[in]      *pState points to the state buffer.    
+ * @param[in]      blockSize is number of samples processed per call.    
+ * @return The function returns ARM_MATH_SUCCESS if initialization is successful or ARM_MATH_ARGUMENT_ERROR if    
+ * <code>numTaps</code> is not greater than or equal to 4 and even.    
+ *    
+ * <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>    
+ * Note that <code>numTaps</code> must be even and greater than or equal to 4.    
+ * To implement an odd length filter simply increase <code>numTaps</code> by 1 and set the last coefficient to zero.    
+ * For example, to implement a filter with <code>numTaps=3</code> and coefficients    
+ * <pre>    
+ *     {0.3, -0.8, 0.3}    
+ * </pre>    
+ * set <code>numTaps=4</code> and use the coefficients:    
+ * <pre>    
+ *     {0.3, -0.8, 0.3, 0}.    
+ * </pre>    
+ * Similarly, to implement a two point filter    
+ * <pre>    
+ *     {0.3, -0.3}    
+ * </pre>    
+ * set <code>numTaps=4</code> and use the coefficients:    
+ * <pre>    
+ *     {0.3, -0.3, 0, 0}.    
+ * </pre>    
+ * \par    
+ * <code>pState</code> points to the array of state variables.    
+ * <code>pState</code> is of length <code>numTaps+blockSize</code>, when running on Cortex-M4 and Cortex-M3  and is of length <code>numTaps+blockSize-1</code>, when running on Cortex-M0 where <code>blockSize</code> is the number of input samples processed by each call to <code>arm_fir_q15()</code>.    
+ */
+
+arm_status arm_fir_init_q15(
+  arm_fir_instance_q15 * S,
+  uint16_t numTaps,
+  q15_t * pCoeffs,
+  q15_t * pState,
+  uint32_t blockSize)
+{
+  arm_status status;
+
+
+#ifndef ARM_MATH_CM0
+
+  /* Run the below code for Cortex-M4 and Cortex-M3 */
+
+  /* The Number of filter coefficients in the filter must be even and at least 4 */
+  if(numTaps & 0x1u)
+  {
+    status = ARM_MATH_ARGUMENT_ERROR;
+  }
+  else
+  {
+    /* Assign filter taps */
+    S->numTaps = numTaps;
+
+    /* Assign coefficient pointer */
+    S->pCoeffs = pCoeffs;
+
+    /* Clear the state buffer.  The size is always (blockSize + numTaps ) */
+    memset(pState, 0, (numTaps + (blockSize)) * sizeof(q15_t));
+
+    /* Assign state pointer */
+    S->pState = pState;
+
+    status = ARM_MATH_SUCCESS;
+  }
+
+  return (status);
+
+#else
+
+  /* Run the below code for Cortex-M0 */
+
+  /* Assign filter taps */
+  S->numTaps = numTaps;
+
+  /* Assign coefficient pointer */
+  S->pCoeffs = pCoeffs;
+
+  /* Clear the state buffer.  The size is always (blockSize + numTaps - 1) */
+  memset(pState, 0, (numTaps + (blockSize - 1u)) * sizeof(q15_t));
+
+  /* Assign state pointer */
+  S->pState = pState;
+
+  status = ARM_MATH_SUCCESS;
+
+  return (status);
+
+#endif /*  #ifndef ARM_MATH_CM0 */
+
+}
+
+/**    
+ * @} end of FIR group    
+ */