Diff: FilteringFunctions/arm_lms_q15.c

Revision:

0:3d9c67d97d6f

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/FilteringFunctions/arm_lms_q15.c	Mon Jul 28 15:03:15 2014 +0000
@@ -0,0 +1,380 @@
+/* ----------------------------------------------------------------------    
+* Copyright (C) 2010-2014 ARM Limited. All rights reserved.    
+*    
+* $Date:        12. March 2014
+* $Revision: 	V1.4.3
+*    
+* Project: 	    CMSIS DSP Library    
+* Title:	    arm_lms_q15.c    
+*    
+* Description:	Processing function for the Q15 LMS 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    
+ * @{    
+ */
+
+ /**    
+ * @brief Processing function for Q15 LMS filter.    
+ * @param[in] *S points to an instance of the Q15 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.    
+ *    
+ * \par Scaling and Overflow Behavior:    
+ * The function is implemented using a 64-bit internal accumulator.    
+ * Both coefficients and state variables are represented in 1.15 format and multiplications yield a 2.30 result.    
+ * The 2.30 intermediate results are accumulated in a 64-bit accumulator in 34.30 format.    
+ * There is no risk of internal overflow with this approach and the full precision of intermediate multiplications is preserved.    
+ * After all additions have been performed, the accumulator is truncated to 34.15 format by discarding low 15 bits.    
+ * Lastly, the accumulator is saturated to yield a result in 1.15 format.    
+ *   
+ * \par   
+ * 	In this filter, filter coefficients are updated for each sample and the updation of filter cofficients are saturted.   
+ *    
+ */
+
+void arm_lms_q15(
+  const arm_lms_instance_q15 * S,
+  q15_t * pSrc,
+  q15_t * pRef,
+  q15_t * pOut,
+  q15_t * pErr,
+  uint32_t blockSize)
+{
+  q15_t *pState = S->pState;                     /* State pointer */
+  uint32_t numTaps = S->numTaps;                 /* Number of filter coefficients in the filter */
+  q15_t *pCoeffs = S->pCoeffs;                   /* Coefficient pointer */
+  q15_t *pStateCurnt;                            /* Points to the current sample of the state */
+  q15_t mu = S->mu;                              /* Adaptive factor */
+  q15_t *px;                                     /* Temporary pointer for state */
+  q15_t *pb;                                     /* Temporary pointer for coefficient buffer */
+  uint32_t tapCnt, blkCnt;                       /* Loop counters */
+  q63_t acc;                                     /* Accumulator */
+  q15_t e = 0;                                   /* error of data sample */
+  q15_t alpha;                                   /* Intermediate constant for taps update */
+  q31_t coef;                                    /* Teporary variable for coefficient */
+  q31_t acc_l, acc_h;
+  int32_t lShift = (15 - (int32_t) S->postShift);       /*  Post shift  */
+  int32_t uShift = (32 - lShift);
+
+
+#ifndef ARM_MATH_CM0_FAMILY
+
+  /* Run the below code for Cortex-M4 and Cortex-M3 */
+
+
+  /* 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)]);
+
+  /* Initializing blkCnt with blockSize */
+  blkCnt = blockSize;
+
+  while(blkCnt > 0u)
+  {
+    /* Copy the new input sample into the state buffer */
+    *pStateCurnt++ = *pSrc++;
+
+    /* Initialize state pointer */
+    px = pState;
+
+    /* Initialize coefficient pointer */
+    pb = pCoeffs;
+
+    /* Set the accumulator to zero */
+    acc = 0;
+
+    /* Loop unrolling.  Process 4 taps at a time. */
+    tapCnt = numTaps >> 2u;
+
+    while(tapCnt > 0u)
+    {
+      /* acc +=  b[N] * x[n-N] + b[N-1] * x[n-N-1] */
+      /* Perform the multiply-accumulate */
+#ifndef UNALIGNED_SUPPORT_DISABLE
+
+      acc = __SMLALD(*__SIMD32(px)++, (*__SIMD32(pb)++), acc);
+      acc = __SMLALD(*__SIMD32(px)++, (*__SIMD32(pb)++), acc);
+
+#else
+
+      acc += (q63_t) (((q31_t) (*px++) * (*pb++)));
+      acc += (q63_t) (((q31_t) (*px++) * (*pb++)));
+      acc += (q63_t) (((q31_t) (*px++) * (*pb++)));
+      acc += (q63_t) (((q31_t) (*px++) * (*pb++)));
+
+
+#endif	/*	#ifndef UNALIGNED_SUPPORT_DISABLE	*/
+
+      /* 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) (((q31_t) (*px++) * (*pb++)));
+
+      /* Decrement the loop counter */
+      tapCnt--;
+    }
+
+    /* Calc lower part of acc */
+    acc_l = acc & 0xffffffff;
+
+    /* Calc upper part of acc */
+    acc_h = (acc >> 32) & 0xffffffff;
+
+    /* Apply shift for lower part of acc and upper part of acc */
+    acc = (uint32_t) acc_l >> lShift | acc_h << uShift;
+
+    /* Converting the result to 1.15 format and saturate the output */
+    acc = __SSAT(acc, 16);
+
+    /* Store the result from accumulator into the destination buffer. */
+    *pOut++ = (q15_t) acc;
+
+    /* Compute and store error */
+    e = *pRef++ - (q15_t) acc;
+
+    *pErr++ = (q15_t) e;
+
+    /* Compute alpha i.e. intermediate constant for taps update */
+    alpha = (q15_t) (((q31_t) e * (mu)) >> 15);
+
+    /* Initialize state pointer */
+    /* Advance state pointer by 1 for the next sample */
+    px = pState++;
+
+    /* Initialize coefficient pointer */
+    pb = pCoeffs;
+
+    /* Loop unrolling.  Process 4 taps at a time. */
+    tapCnt = numTaps >> 2u;
+
+    /* Update filter coefficients */
+    while(tapCnt > 0u)
+    {
+      coef = (q31_t) * pb + (((q31_t) alpha * (*px++)) >> 15);
+      *pb++ = (q15_t) __SSAT((coef), 16);
+      coef = (q31_t) * pb + (((q31_t) alpha * (*px++)) >> 15);
+      *pb++ = (q15_t) __SSAT((coef), 16);
+      coef = (q31_t) * pb + (((q31_t) alpha * (*px++)) >> 15);
+      *pb++ = (q15_t) __SSAT((coef), 16);
+      coef = (q31_t) * pb + (((q31_t) alpha * (*px++)) >> 15);
+      *pb++ = (q15_t) __SSAT((coef), 16);
+
+      /* 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) * pb + (((q31_t) alpha * (*px++)) >> 15);
+      *pb++ = (q15_t) __SSAT((coef), 16);
+
+      /* Decrement the loop counter */
+      tapCnt--;
+    }
+
+    /* Decrement the loop counter */
+    blkCnt--;
+
+  }
+
+  /* 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;
+
+  /* Calculation of count for copying integer writes */
+  tapCnt = (numTaps - 1u) >> 2;
+
+  while(tapCnt > 0u)
+  {
+
+#ifndef UNALIGNED_SUPPORT_DISABLE
+
+    *__SIMD32(pStateCurnt)++ = *__SIMD32(pState)++;
+    *__SIMD32(pStateCurnt)++ = *__SIMD32(pState)++;
+#else
+    *pStateCurnt++ = *pState++;
+    *pStateCurnt++ = *pState++;
+    *pStateCurnt++ = *pState++;
+    *pStateCurnt++ = *pState++;
+#endif
+
+    tapCnt--;
+
+  }
+
+  /* Calculation of count for remaining q15_t data */
+  tapCnt = (numTaps - 1u) % 0x4u;
+
+  /* copy data */
+  while(tapCnt > 0u)
+  {
+    *pStateCurnt++ = *pState++;
+
+    /* Decrement the loop counter */
+    tapCnt--;
+  }
+
+#else
+
+  /* Run the below code for Cortex-M0 */
+
+  /* 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;
+
+  while(blkCnt > 0u)
+  {
+    /* Copy the new input sample into the state buffer */
+    *pStateCurnt++ = *pSrc++;
+
+    /* Initialize pState pointer */
+    px = pState;
+
+    /* Initialize pCoeffs pointer */
+    pb = pCoeffs;
+
+    /* 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) ((q31_t) (*px++) * (*pb++));
+
+      /* Decrement the loop counter */
+      tapCnt--;
+    }
+
+    /* Calc lower part of acc */
+    acc_l = acc & 0xffffffff;
+
+    /* Calc upper part of acc */
+    acc_h = (acc >> 32) & 0xffffffff;
+
+    /* Apply shift for lower part of acc and upper part of acc */
+    acc = (uint32_t) acc_l >> lShift | acc_h << uShift;
+
+    /* Converting the result to 1.15 format and saturate the output */
+    acc = __SSAT(acc, 16);
+
+    /* Store the result from accumulator into the destination buffer. */
+    *pOut++ = (q15_t) acc;
+
+    /* Compute and store error */
+    e = *pRef++ - (q15_t) acc;
+
+    *pErr++ = (q15_t) e;
+
+    /* Compute alpha i.e. intermediate constant for taps update */
+    alpha = (q15_t) (((q31_t) e * (mu)) >> 15);
+
+    /* Initialize pState pointer */
+    /* Advance state pointer by 1 for the next sample */
+    px = pState++;
+
+    /* Initialize pCoeffs pointer */
+    pb = pCoeffs;
+
+    /* Loop over numTaps number of values */
+    tapCnt = numTaps;
+
+    while(tapCnt > 0u)
+    {
+      /* Perform the multiply-accumulate */
+      coef = (q31_t) * pb + (((q31_t) alpha * (*px++)) >> 15);
+      *pb++ = (q15_t) __SSAT((coef), 16);
+
+      /* Decrement the loop counter */
+      tapCnt--;
+    }
+
+    /* Decrement the loop counter */
+    blkCnt--;
+
+  }
+
+  /* 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;
+
+  /*  Copy (numTaps - 1u) samples  */
+  tapCnt = (numTaps - 1u);
+
+  /* Copy the data */
+  while(tapCnt > 0u)
+  {
+    *pStateCurnt++ = *pState++;
+
+    /* Decrement the loop counter */
+    tapCnt--;
+  }
+
+#endif /*   #ifndef ARM_MATH_CM0_FAMILY */
+
+}
+
+/**    
+   * @} end of LMS group    
+   */