Diff: FilteringFunctions/arm_lms_norm_q31.c

Revision:

0:3d9c67d97d6f

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/FilteringFunctions/arm_lms_norm_q31.c	Mon Jul 28 15:03:15 2014 +0000
@@ -0,0 +1,431 @@
+/* ----------------------------------------------------------------------    
+* Copyright (C) 2010-2014 ARM Limited. All rights reserved.    
+*    
+* $Date:        12. March 2014
+* $Revision: 	V1.4.3
+*    
+* Project: 	    CMSIS DSP Library    
+* Title:	    arm_lms_norm_q31.c    
+*    
+* Description:	Processing function for the Q31 NLMS filter.    
+*    
+* 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 LMS_NORM    
+ * @{    
+ */
+
+/**    
+* @brief Processing function for Q31 normalized LMS filter.    
+* @param[in] *S points to an instance of the Q31 normalized LMS filter structure.    
+* @param[in] *pSrc points to the block of input data.    
+* @param[in] *pRef points to the block of reference data.    
+* @param[out] *pOut points to the block of output data.    
+* @param[out] *pErr points to the block of error data.    
+* @param[in] blockSize number of samples to process.    
+* @return none.    
+*    
+* <b>Scaling and Overflow Behavior:</b>     
+* \par     
+* The function is implemented using an internal 64-bit accumulator.     
+* The accumulator has a 2.62 format and maintains full precision of the intermediate   
+* multiplication results but provides only a single guard bit.     
+* Thus, if the accumulator result overflows it wraps around rather than clip.     
+* In order to avoid overflows completely the input signal must be scaled down by    
+* log2(numTaps) bits. The reference signal should not be scaled down.     
+* After all multiply-accumulates are performed, the 2.62 accumulator is shifted    
+* and saturated to 1.31 format to yield the final result.     
+* The output signal and error signal are in 1.31 format.     
+*    
+* \par    
+* 	In this filter, filter coefficients are updated for each sample and the    
+* updation of filter cofficients are saturted.    
+*     
+*/
+
+void arm_lms_norm_q31(
+  arm_lms_norm_instance_q31 * S,
+  q31_t * pSrc,
+  q31_t * pRef,
+  q31_t * pOut,
+  q31_t * pErr,
+  uint32_t blockSize)
+{
+  q31_t *pState = S->pState;                     /* State pointer */
+  q31_t *pCoeffs = S->pCoeffs;                   /* Coefficient pointer */
+  q31_t *pStateCurnt;                            /* Points to the current sample of the state */
+  q31_t *px, *pb;                                /* Temporary pointers for state and coefficient buffers */
+  q31_t mu = S->mu;                              /* Adaptive factor */
+  uint32_t numTaps = S->numTaps;                 /* Number of filter coefficients in the filter */
+  uint32_t tapCnt, blkCnt;                       /* Loop counters */
+  q63_t energy;                                  /* Energy of the input */
+  q63_t acc;                                     /* Accumulator */
+  q31_t e = 0, d = 0;                            /* error, reference data sample */
+  q31_t w = 0, in;                               /* weight factor and state */
+  q31_t x0;                                      /* temporary variable to hold input sample */
+//  uint32_t shift = 32u - ((uint32_t) S->postShift + 1u);        /* Shift to be applied to the output */      
+  q31_t errorXmu, oneByEnergy;                   /* Temporary variables to store error and mu product and reciprocal of energy */
+  q31_t postShift;                               /* Post shift to be applied to weight after reciprocal calculation */
+  q31_t coef;                                    /* Temporary variable for coef */
+  q31_t acc_l, acc_h;                            /*  temporary input */
+  uint32_t uShift = ((uint32_t) S->postShift + 1u);
+  uint32_t lShift = 32u - uShift;                /*  Shift to be applied to the output */
+
+  energy = S->energy;
+  x0 = S->x0;
+
+  /* S->pState points to buffer which contains previous frame (numTaps - 1) samples */
+  /* pStateCurnt points to the location where the new input data should be written */
+  pStateCurnt = &(S->pState[(numTaps - 1u)]);
+
+  /* Loop over blockSize number of values */
+  blkCnt = blockSize;
+
+
+#ifndef ARM_MATH_CM0_FAMILY
+
+  /* Run the below code for Cortex-M4 and Cortex-M3 */
+
+  while(blkCnt > 0u)
+  {
+
+    /* Copy the new input sample into the state buffer */
+    *pStateCurnt++ = *pSrc;
+
+    /* Initialize pState pointer */
+    px = pState;
+
+    /* Initialize coeff pointer */
+    pb = (pCoeffs);
+
+    /* Read the sample from input buffer */
+    in = *pSrc++;
+
+    /* Update the energy calculation */
+    energy = (q31_t) ((((q63_t) energy << 32) -
+                       (((q63_t) x0 * x0) << 1)) >> 32);
+    energy = (q31_t) (((((q63_t) in * in) << 1) + (energy << 32)) >> 32);
+
+    /* Set the accumulator to zero */
+    acc = 0;
+
+    /* Loop unrolling.  Process 4 taps at a time. */
+    tapCnt = numTaps >> 2;
+
+    while(tapCnt > 0u)
+    {
+      /* Perform the multiply-accumulate */
+      acc += ((q63_t) (*px++)) * (*pb++);
+      acc += ((q63_t) (*px++)) * (*pb++);
+      acc += ((q63_t) (*px++)) * (*pb++);
+      acc += ((q63_t) (*px++)) * (*pb++);
+
+      /* Decrement the loop counter */
+      tapCnt--;
+    }
+
+    /* If the filter length is not a multiple of 4, compute the remaining filter taps */
+    tapCnt = numTaps % 0x4u;
+
+    while(tapCnt > 0u)
+    {
+      /* Perform the multiply-accumulate */
+      acc += ((q63_t) (*px++)) * (*pb++);
+
+      /* Decrement the loop counter */
+      tapCnt--;
+    }
+
+    /* Converting the result to 1.31 format */
+    /* Calc lower part of acc */
+    acc_l = acc & 0xffffffff;
+
+    /* Calc upper part of acc */
+    acc_h = (acc >> 32) & 0xffffffff;
+
+    acc = (uint32_t) acc_l >> lShift | acc_h << uShift;
+
+    /* Store the result from accumulator into the destination buffer. */
+    *pOut++ = (q31_t) acc;
+
+    /* Compute and store error */
+    d = *pRef++;
+    e = d - (q31_t) acc;
+    *pErr++ = e;
+
+    /* Calculates the reciprocal of energy */
+    postShift = arm_recip_q31(energy + DELTA_Q31,
+                              &oneByEnergy, &S->recipTable[0]);
+
+    /* Calculation of product of (e * mu) */
+    errorXmu = (q31_t) (((q63_t) e * mu) >> 31);
+
+    /* Weighting factor for the normalized version */
+    w = clip_q63_to_q31(((q63_t) errorXmu * oneByEnergy) >> (31 - postShift));
+
+    /* Initialize pState pointer */
+    px = pState;
+
+    /* Initialize coeff pointer */
+    pb = (pCoeffs);
+
+    /* Loop unrolling.  Process 4 taps at a time. */
+    tapCnt = numTaps >> 2;
+
+    /* Update filter coefficients */
+    while(tapCnt > 0u)
+    {
+      /* Perform the multiply-accumulate */
+
+      /* coef is in 2.30 format */
+      coef = (q31_t) (((q63_t) w * (*px++)) >> (32));
+      /* get coef in 1.31 format by left shifting */
+      *pb = clip_q63_to_q31((q63_t) * pb + (coef << 1u));
+      /* update coefficient buffer to next coefficient */
+      pb++;
+
+      coef = (q31_t) (((q63_t) w * (*px++)) >> (32));
+      *pb = clip_q63_to_q31((q63_t) * pb + (coef << 1u));
+      pb++;
+
+      coef = (q31_t) (((q63_t) w * (*px++)) >> (32));
+      *pb = clip_q63_to_q31((q63_t) * pb + (coef << 1u));
+      pb++;
+
+      coef = (q31_t) (((q63_t) w * (*px++)) >> (32));
+      *pb = clip_q63_to_q31((q63_t) * pb + (coef << 1u));
+      pb++;
+
+      /* Decrement the loop counter */
+      tapCnt--;
+    }
+
+    /* If the filter length is not a multiple of 4, compute the remaining filter taps */
+    tapCnt = numTaps % 0x4u;
+
+    while(tapCnt > 0u)
+    {
+      /* Perform the multiply-accumulate */
+      coef = (q31_t) (((q63_t) w * (*px++)) >> (32));
+      *pb = clip_q63_to_q31((q63_t) * pb + (coef << 1u));
+      pb++;
+
+      /* Decrement the loop counter */
+      tapCnt--;
+    }
+
+    /* Read the sample from state buffer */
+    x0 = *pState;
+
+    /* Advance state pointer by 1 for the next sample */
+    pState = pState + 1;
+
+    /* Decrement the loop counter */
+    blkCnt--;
+  }
+
+  /* Save energy and x0 values for the next frame */
+  S->energy = (q31_t) energy;
+  S->x0 = x0;
+
+  /* Processing is complete. Now copy the last numTaps - 1 samples to the    
+     satrt of the state buffer. This prepares the state buffer for the    
+     next function call. */
+
+  /* Points to the start of the pState buffer */
+  pStateCurnt = S->pState;
+
+  /* Loop unrolling for (numTaps - 1u) samples copy */
+  tapCnt = (numTaps - 1u) >> 2u;
+
+  /* copy data */
+  while(tapCnt > 0u)
+  {
+    *pStateCurnt++ = *pState++;
+    *pStateCurnt++ = *pState++;
+    *pStateCurnt++ = *pState++;
+    *pStateCurnt++ = *pState++;
+
+    /* Decrement the loop counter */
+    tapCnt--;
+  }
+
+  /* Calculate remaining number of copies */
+  tapCnt = (numTaps - 1u) % 0x4u;
+
+  /* Copy the remaining q31_t data */
+  while(tapCnt > 0u)
+  {
+    *pStateCurnt++ = *pState++;
+
+    /* Decrement the loop counter */
+    tapCnt--;
+  }
+
+#else
+
+  /* Run the below code for Cortex-M0 */
+
+  while(blkCnt > 0u)
+  {
+
+    /* Copy the new input sample into the state buffer */
+    *pStateCurnt++ = *pSrc;
+
+    /* Initialize pState pointer */
+    px = pState;
+
+    /* Initialize pCoeffs pointer */
+    pb = pCoeffs;
+
+    /* Read the sample from input buffer */
+    in = *pSrc++;
+
+    /* Update the energy calculation */
+    energy =
+      (q31_t) ((((q63_t) energy << 32) - (((q63_t) x0 * x0) << 1)) >> 32);
+    energy = (q31_t) (((((q63_t) in * in) << 1) + (energy << 32)) >> 32);
+
+    /* Set the accumulator to zero */
+    acc = 0;
+
+    /* Loop over numTaps number of values */
+    tapCnt = numTaps;
+
+    while(tapCnt > 0u)
+    {
+      /* Perform the multiply-accumulate */
+      acc += ((q63_t) (*px++)) * (*pb++);
+
+      /* Decrement the loop counter */
+      tapCnt--;
+    }
+
+    /* Converting the result to 1.31 format */
+    /* Converting the result to 1.31 format */
+    /* Calc lower part of acc */
+    acc_l = acc & 0xffffffff;
+
+    /* Calc upper part of acc */
+    acc_h = (acc >> 32) & 0xffffffff;
+
+    acc = (uint32_t) acc_l >> lShift | acc_h << uShift;
+
+
+    //acc = (q31_t) (acc >> shift); 
+
+    /* Store the result from accumulator into the destination buffer. */
+    *pOut++ = (q31_t) acc;
+
+    /* Compute and store error */
+    d = *pRef++;
+    e = d - (q31_t) acc;
+    *pErr++ = e;
+
+    /* Calculates the reciprocal of energy */
+    postShift =
+      arm_recip_q31(energy + DELTA_Q31, &oneByEnergy, &S->recipTable[0]);
+
+    /* Calculation of product of (e * mu) */
+    errorXmu = (q31_t) (((q63_t) e * mu) >> 31);
+
+    /* Weighting factor for the normalized version */
+    w = clip_q63_to_q31(((q63_t) errorXmu * oneByEnergy) >> (31 - postShift));
+
+    /* Initialize pState pointer */
+    px = pState;
+
+    /* Initialize coeff pointer */
+    pb = (pCoeffs);
+
+    /* Loop over numTaps number of values */
+    tapCnt = numTaps;
+
+    while(tapCnt > 0u)
+    {
+      /* Perform the multiply-accumulate */
+      /* coef is in 2.30 format */
+      coef = (q31_t) (((q63_t) w * (*px++)) >> (32));
+      /* get coef in 1.31 format by left shifting */
+      *pb = clip_q63_to_q31((q63_t) * pb + (coef << 1u));
+      /* update coefficient buffer to next coefficient */
+      pb++;
+
+      /* Decrement the loop counter */
+      tapCnt--;
+    }
+
+    /* Read the sample from state buffer */
+    x0 = *pState;
+
+    /* Advance state pointer by 1 for the next sample */
+    pState = pState + 1;
+
+    /* Decrement the loop counter */
+    blkCnt--;
+  }
+
+  /* Save energy and x0 values for the next frame */
+  S->energy = (q31_t) energy;
+  S->x0 = x0;
+
+  /* Processing is complete. Now copy the last numTaps - 1 samples to the     
+     start of the state buffer. This prepares the state buffer for the        
+     next function call. */
+
+  /* Points to the start of the pState buffer */
+  pStateCurnt = S->pState;
+
+  /* Loop for (numTaps - 1u) samples copy */
+  tapCnt = (numTaps - 1u);
+
+  /* Copy the remaining q31_t data */
+  while(tapCnt > 0u)
+  {
+    *pStateCurnt++ = *pState++;
+
+    /* Decrement the loop counter */
+    tapCnt--;
+  }
+
+#endif /*   #ifndef ARM_MATH_CM0_FAMILY */
+
+}
+
+/**    
+ * @} end of LMS_NORM group    
+ */