##// END OF EJS Templates
HG_REPOSITORIES » LPP » INSTRUMENTATION » libuc2
RSS

Clone from http://pc-instru.lpp.polytechnique.fr:5000/libuc2

Generic lib clean target bug fixed
Generic lib clean target bug fixed
jeandet@pc-de-jeandet3.lab-lpp.local - - Load All Authors

File last commit:

r16:194f637a2640 default
r17:24654bf85fa1 default
Show More
arm_lms_norm_q15.c
260 lines | 8.3 KiB | text/x-c | CLexer
/ lib / src / lpc17XX / CMSIS / MATH / arm_lms_norm_q15.c
History | Source | Raw |Copy content |Copy permalink
jeandet@pc-de-jeandet3.lab-lpp.local
Cleaned source tree....
 r16 /* ----------------------------------------------------------------------
* Copyright (C) 2010 ARM Limited. All rights reserved.
*
* $Date: 29. November 2010
* $Revision: V1.0.3
*
* Project: CMSIS DSP Library
* Title: arm_lms_norm_q15.c
*
* Description: Q15 NLMS filter.
*
* Target Processor: Cortex-M4/Cortex-M3
*
* 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 LMS_NORM
* @{
*/
/**
* @brief Processing function for Q15 normalized LMS filter.
* @param[in] *S points to an instance of the Q15 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 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_norm_q15(
arm_lms_norm_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 */
q15_t *pCoeffs = S->pCoeffs; /* Coefficient pointer */
q15_t *pStateCurnt; /* Points to the current sample of the state */
q15_t *px, *pb; /* Temporary pointers for state and coefficient buffers */
q15_t mu = S->mu; /* Adaptive factor */
uint32_t numTaps = S->numTaps; /* Number of filter coefficients in the filter */
uint32_t tapCnt, blkCnt; /* Loop counters */
q31_t energy; /* Energy of the input */
q63_t acc; /* Accumulator */
q15_t e = 0, d = 0; /* error, reference data sample */
q15_t w = 0, in; /* weight factor and state */
q15_t x0; /* temporary variable to hold input sample */
uint32_t shift = (uint32_t) S->postShift + 1u; /* Shift to be applied to the output */
q15_t errorXmu, oneByEnergy; /* Temporary variables to store error and mu product and reciprocal of energy */
q15_t postShift; /* Post shift to be applied to weight after reciprocal calculation */
q31_t coef; /* Teporary variable for coefficient */
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)]);
blkCnt = blockSize;
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) x0 * (x0)) >> 15);
energy += (((q31_t) in * (in)) >> 15);
/* 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 = __SMLALD(*__SIMD32(px)++, (*__SIMD32(pb)++), acc);
acc = __SMLALD(*__SIMD32(px)++, (*__SIMD32(pb)++), acc);
/* 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 += (((q31_t) * px++ * (*pb++)));
/* Decrement the loop counter */
tapCnt--;
}
/* Converting the result to 1.15 format */
acc = __SSAT((acc >> (16u - shift)), 16u);
/* Store the result from accumulator into the destination buffer. */
*pOut++ = (q15_t) acc;
/* Compute and store error */
d = *pRef++;
e = d - (q15_t) acc;
*pErr++ = e;
/* Calculation of 1/energy */
postShift = arm_recip_q15((q15_t) energy + DELTA_Q15,
&oneByEnergy, S->recipTable);
/* Calculation of e * mu value */
errorXmu = (q15_t) (((q31_t) e * mu) >> 15);
/* Calculation of (e * mu) * (1/energy) value */
acc = (((q31_t) errorXmu * oneByEnergy) >> (15 - postShift));
/* Weighting factor for the normalized version */
w = (q15_t) __SSAT((q31_t) acc, 16);
/* 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)
{
coef = *pb + (((q31_t) w * (*px++)) >> 15);
*pb++ = (q15_t) __SSAT((coef), 16);
coef = *pb + (((q31_t) w * (*px++)) >> 15);
*pb++ = (q15_t) __SSAT((coef), 16);
coef = *pb + (((q31_t) w * (*px++)) >> 15);
*pb++ = (q15_t) __SSAT((coef), 16);
coef = *pb + (((q31_t) w * (*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 = *pb + (((q31_t) w * (*px++)) >> 15);
*pb++ = (q15_t) __SSAT((coef), 16);
/* Decrement the loop counter */
tapCnt--;
}
/* Read the sample from state buffer */
x0 = *pState;
/* Advance state pointer by 1 for the next sample */
pState = pState + 1u;
/* Decrement the loop counter */
blkCnt--;
}
/* Save energy and x0 values for the next frame */
S->energy = (q15_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;
/* Calculation of count for copying integer writes */
tapCnt = (numTaps - 1u) >> 2;
while(tapCnt > 0u)
{
*__SIMD32(pStateCurnt)++ = *__SIMD32(pState)++;
*__SIMD32(pStateCurnt)++ = *__SIMD32(pState)++;
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--;
}
}
/**
* @} end of LMS_NORM group
*/