Diff: cmsis_dsp/StatisticsFunctions/arm_rms_f32.c

Revision:

1:fdd22bb7aa52

Child:

2:da51fb522205

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/cmsis_dsp/StatisticsFunctions/arm_rms_f32.c	Wed Nov 28 12:30:09 2012 +0000
@@ -0,0 +1,133 @@
+/* ----------------------------------------------------------------------    
+* Copyright (C) 2010 ARM Limited. All rights reserved.    
+*    
+* $Date:        15. February 2012  
+* $Revision:     V1.1.0  
+*    
+* Project:         CMSIS DSP Library    
+* Title:        arm_rms_f32.c    
+*    
+* Description:    Root mean square value of an array of F32 type    
+*    
+* 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.    
+* ---------------------------------------------------------------------------- */
+
+#include "arm_math.h"
+
+/**    
+ * @ingroup groupStats    
+ */
+
+/**    
+ * @defgroup RMS Root mean square (RMS)    
+ *    
+ *     
+ * Calculates the Root Mean Sqaure of the elements in the input vector.    
+ * The underlying algorithm is used:    
+ *    
+ * <pre>    
+ *     Result = sqrt(((pSrc[0] * pSrc[0] + pSrc[1] * pSrc[1] + ... + pSrc[blockSize-1] * pSrc[blockSize-1]) / blockSize));    
+ * </pre>    
+ *   
+ * There are separate functions for floating point, Q31, and Q15 data types.     
+ */
+
+/**    
+ * @addtogroup RMS    
+ * @{    
+ */
+
+
+/**    
+ * @brief Root Mean Square of the elements of a floating-point vector.    
+ * @param[in]       *pSrc points to the input vector    
+ * @param[in]       blockSize length of the input vector    
+ * @param[out]      *pResult rms value returned here    
+ * @return none.    
+ *    
+ */
+
+void arm_rms_f32(
+  float32_t * pSrc,
+  uint32_t blockSize,
+  float32_t * pResult)
+{
+  float32_t sum = 0.0f;                          /* Accumulator */
+  float32_t in;                                  /* Tempoprary variable to store input value */
+  uint32_t blkCnt;                               /* loop counter */
+
+#ifndef ARM_MATH_CM0
+
+  /* Run the below code for Cortex-M4 and Cortex-M3 */
+
+  /* loop Unrolling */
+  blkCnt = blockSize >> 2u;
+
+  /* First part of the processing with loop unrolling.  Compute 4 outputs at a time.    
+   ** a second loop below computes the remaining 1 to 3 samples. */
+  while(blkCnt > 0u)
+  {
+    /* C = A[0] * A[0] + A[1] * A[1] + A[2] * A[2] + ... + A[blockSize-1] * A[blockSize-1] */
+    /* Compute sum of the squares and then store the result in a temporary variable, sum  */
+    in = *pSrc++;
+    sum += in * in;
+    in = *pSrc++;
+    sum += in * in;
+    in = *pSrc++;
+    sum += in * in;
+    in = *pSrc++;
+    sum += in * in;
+
+    /* Decrement the loop counter */
+    blkCnt--;
+  }
+
+  /* If the blockSize is not a multiple of 4, compute any remaining output samples here.    
+   ** No loop unrolling is used. */
+  blkCnt = blockSize % 0x4u;
+
+#else
+
+  /* Run the below code for Cortex-M0 */
+
+  /* Loop over blockSize number of values */
+  blkCnt = blockSize;
+
+#endif /* #ifndef ARM_MATH_CM0 */
+
+  while(blkCnt > 0u)
+  {
+    /* C = A[0] * A[0] + A[1] * A[1] + A[2] * A[2] + ... + A[blockSize-1] * A[blockSize-1] */
+    /* Compute sum of the squares and then store the results in a temporary variable, sum  */
+    in = *pSrc++;
+    sum += in * in;
+
+    /* Decrement the loop counter */
+    blkCnt--;
+  }
+
+  /* Compute Rms and store the result in the destination */
+  arm_sqrt_f32(sum / (float32_t) blockSize, pResult);
+}
+
+/**    
+ * @} end of RMS group    
+ */