arm_fir_sparse_q31.c
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CLexer
r71 | /* ---------------------------------------------------------------------- | |||
* Copyright (C) 2010 ARM Limited. All rights reserved. | ||||
* | ||||
* $Date: 15. July 2011 | ||||
* $Revision: V1.0.10 | ||||
* | ||||
* Project: CMSIS DSP Library | ||||
* Title: arm_fir_sparse_q31.c | ||||
* | ||||
* Description: Q31 sparse FIR filter processing function. | ||||
* | ||||
* Target Processor: Cortex-M4/Cortex-M3/Cortex-M0 | ||||
* | ||||
* 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 0.0.7 2010/06/10 | ||||
* Misra-C changes done | ||||
* ------------------------------------------------------------------- */ | ||||
#include "arm_math.h" | ||||
/** | ||||
* @addtogroup FIR_Sparse | ||||
* @{ | ||||
*/ | ||||
/** | ||||
* @brief Processing function for the Q31 sparse FIR filter. | ||||
* @param[in] *S points to an instance of the Q31 sparse FIR structure. | ||||
* @param[in] *pSrc points to the block of input data. | ||||
* @param[out] *pDst points to the block of output data | ||||
* @param[in] *pScratchIn points to a temporary buffer of size blockSize. | ||||
* @param[in] blockSize number of input samples to process per call. | ||||
* @return none. | ||||
* | ||||
* <b>Scaling and Overflow Behavior:</b> | ||||
* \par | ||||
* The function is implemented using an internal 32-bit accumulator. | ||||
* The 1.31 x 1.31 multiplications are truncated to 2.30 format. | ||||
* This leads to loss of precision on the intermediate multiplications and provides only a single guard bit. | ||||
* If the accumulator result overflows, it wraps around rather than saturate. | ||||
* In order to avoid overflows the input signal or coefficients must be scaled down by log2(numTaps) bits. | ||||
*/ | ||||
void arm_fir_sparse_q31( | ||||
arm_fir_sparse_instance_q31 * S, | ||||
q31_t * pSrc, | ||||
q31_t * pDst, | ||||
q31_t * pScratchIn, | ||||
uint32_t blockSize) | ||||
{ | ||||
q31_t *pState = S->pState; /* State pointer */ | ||||
q31_t *pCoeffs = S->pCoeffs; /* Coefficient pointer */ | ||||
q31_t *px; /* Scratch buffer pointer */ | ||||
q31_t *py = pState; /* Temporary pointers for state buffer */ | ||||
q31_t *pb = pScratchIn; /* Temporary pointers for scratch buffer */ | ||||
q31_t *pOut; /* Destination pointer */ | ||||
q63_t out; /* Temporary output variable */ | ||||
int32_t *pTapDelay = S->pTapDelay; /* Pointer to the array containing offset of the non-zero tap values. */ | ||||
uint32_t delaySize = S->maxDelay + blockSize; /* state length */ | ||||
uint16_t numTaps = S->numTaps; /* Filter order */ | ||||
int32_t readIndex; /* Read index of the state buffer */ | ||||
uint32_t tapCnt, blkCnt; /* loop counters */ | ||||
q31_t coeff = *pCoeffs++; /* Read the first coefficient value */ | ||||
q31_t in; | ||||
/* BlockSize of Input samples are copied into the state buffer */ | ||||
/* StateIndex points to the starting position to write in the state buffer */ | ||||
arm_circularWrite_f32((int32_t *) py, delaySize, &S->stateIndex, 1, | ||||
(int32_t *) pSrc, 1, blockSize); | ||||
/* Read Index, from where the state buffer should be read, is calculated. */ | ||||
readIndex = (int32_t) (S->stateIndex - blockSize) - *pTapDelay++; | ||||
/* Wraparound of readIndex */ | ||||
if(readIndex < 0) | ||||
{ | ||||
readIndex += (int32_t) delaySize; | ||||
} | ||||
/* Working pointer for state buffer is updated */ | ||||
py = pState; | ||||
/* blockSize samples are read from the state buffer */ | ||||
arm_circularRead_f32((int32_t *) py, delaySize, &readIndex, 1, | ||||
(int32_t *) pb, (int32_t *) pb, blockSize, 1, | ||||
blockSize); | ||||
/* Working pointer for the scratch buffer of state values */ | ||||
px = pb; | ||||
/* Working pointer for scratch buffer of output values */ | ||||
pOut = pDst; | ||||
#ifndef ARM_MATH_CM0 | ||||
/* Run the below code for Cortex-M4 and Cortex-M3 */ | ||||
/* Loop over the blockSize. Unroll by a factor of 4. | ||||
* Compute 4 Multiplications at a time. */ | ||||
blkCnt = blockSize >> 2; | ||||
while(blkCnt > 0u) | ||||
{ | ||||
/* Perform Multiplications and store in the destination buffer */ | ||||
*pOut++ = (q31_t) (((q63_t) * px++ * coeff) >> 32); | ||||
*pOut++ = (q31_t) (((q63_t) * px++ * coeff) >> 32); | ||||
*pOut++ = (q31_t) (((q63_t) * px++ * coeff) >> 32); | ||||
*pOut++ = (q31_t) (((q63_t) * px++ * coeff) >> 32); | ||||
/* Decrement the loop counter */ | ||||
blkCnt--; | ||||
} | ||||
/* If the blockSize is not a multiple of 4, | ||||
* compute the remaining samples */ | ||||
blkCnt = blockSize % 0x4u; | ||||
while(blkCnt > 0u) | ||||
{ | ||||
/* Perform Multiplications and store in the destination buffer */ | ||||
*pOut++ = (q31_t) (((q63_t) * px++ * coeff) >> 32); | ||||
/* Decrement the loop counter */ | ||||
blkCnt--; | ||||
} | ||||
/* Load the coefficient value and | ||||
* increment the coefficient buffer for the next set of state values */ | ||||
coeff = *pCoeffs++; | ||||
/* Read Index, from where the state buffer should be read, is calculated. */ | ||||
readIndex = (int32_t) (S->stateIndex - blockSize) - *pTapDelay++; | ||||
/* Wraparound of readIndex */ | ||||
if(readIndex < 0) | ||||
{ | ||||
readIndex += (int32_t) delaySize; | ||||
} | ||||
/* Loop over the number of taps. */ | ||||
tapCnt = (uint32_t) numTaps - 1u; | ||||
while(tapCnt > 0u) | ||||
{ | ||||
/* Working pointer for state buffer is updated */ | ||||
py = pState; | ||||
/* blockSize samples are read from the state buffer */ | ||||
arm_circularRead_f32((int32_t *) py, delaySize, &readIndex, 1, | ||||
(int32_t *) pb, (int32_t *) pb, blockSize, 1, | ||||
blockSize); | ||||
/* Working pointer for the scratch buffer of state values */ | ||||
px = pb; | ||||
/* Working pointer for scratch buffer of output values */ | ||||
pOut = pDst; | ||||
/* Loop over the blockSize. Unroll by a factor of 4. | ||||
* Compute 4 MACS at a time. */ | ||||
blkCnt = blockSize >> 2; | ||||
while(blkCnt > 0u) | ||||
{ | ||||
out = *pOut; | ||||
out += ((q63_t) * px++ * coeff) >> 32; | ||||
*pOut++ = (q31_t) (out); | ||||
out = *pOut; | ||||
out += ((q63_t) * px++ * coeff) >> 32; | ||||
*pOut++ = (q31_t) (out); | ||||
out = *pOut; | ||||
out += ((q63_t) * px++ * coeff) >> 32; | ||||
*pOut++ = (q31_t) (out); | ||||
out = *pOut; | ||||
out += ((q63_t) * px++ * coeff) >> 32; | ||||
*pOut++ = (q31_t) (out); | ||||
/* Decrement the loop counter */ | ||||
blkCnt--; | ||||
} | ||||
/* If the blockSize is not a multiple of 4, | ||||
* compute the remaining samples */ | ||||
blkCnt = blockSize % 0x4u; | ||||
while(blkCnt > 0u) | ||||
{ | ||||
/* Perform Multiply-Accumulate */ | ||||
out = *pOut; | ||||
out += ((q63_t) * px++ * coeff) >> 32; | ||||
*pOut++ = (q31_t) (out); | ||||
/* Decrement the loop counter */ | ||||
blkCnt--; | ||||
} | ||||
/* Load the coefficient value and | ||||
* increment the coefficient buffer for the next set of state values */ | ||||
coeff = *pCoeffs++; | ||||
/* Read Index, from where the state buffer should be read, is calculated. */ | ||||
readIndex = (int32_t) (S->stateIndex - blockSize) - *pTapDelay++; | ||||
/* Wraparound of readIndex */ | ||||
if(readIndex < 0) | ||||
{ | ||||
readIndex += (int32_t) delaySize; | ||||
} | ||||
/* Decrement the tap loop counter */ | ||||
tapCnt--; | ||||
} | ||||
/* Working output pointer is updated */ | ||||
pOut = pDst; | ||||
/* Output is converted into 1.31 format. */ | ||||
/* Loop over the blockSize. Unroll by a factor of 4. | ||||
* process 4 output samples at a time. */ | ||||
blkCnt = blockSize >> 2; | ||||
while(blkCnt > 0u) | ||||
{ | ||||
in = *pOut << 1; | ||||
*pOut++ = in; | ||||
in = *pOut << 1; | ||||
*pOut++ = in; | ||||
in = *pOut << 1; | ||||
*pOut++ = in; | ||||
in = *pOut << 1; | ||||
*pOut++ = in; | ||||
/* Decrement the loop counter */ | ||||
blkCnt--; | ||||
} | ||||
/* If the blockSize is not a multiple of 4, | ||||
* process the remaining output samples */ | ||||
blkCnt = blockSize % 0x4u; | ||||
while(blkCnt > 0u) | ||||
{ | ||||
in = *pOut << 1; | ||||
*pOut++ = in; | ||||
/* Decrement the loop counter */ | ||||
blkCnt--; | ||||
} | ||||
#else | ||||
/* Run the below code for Cortex-M0 */ | ||||
blkCnt = blockSize; | ||||
while(blkCnt > 0u) | ||||
{ | ||||
/* Perform Multiplications and store in the destination buffer */ | ||||
*pOut++ = (q31_t) (((q63_t) * px++ * coeff) >> 32); | ||||
/* Decrement the loop counter */ | ||||
blkCnt--; | ||||
} | ||||
/* Load the coefficient value and | ||||
* increment the coefficient buffer for the next set of state values */ | ||||
coeff = *pCoeffs++; | ||||
/* Read Index, from where the state buffer should be read, is calculated. */ | ||||
readIndex = (int32_t) (S->stateIndex - blockSize) - *pTapDelay++; | ||||
/* Wraparound of readIndex */ | ||||
if(readIndex < 0) | ||||
{ | ||||
readIndex += (int32_t) delaySize; | ||||
} | ||||
/* Loop over the number of taps. */ | ||||
tapCnt = (uint32_t) numTaps - 1u; | ||||
while(tapCnt > 0u) | ||||
{ | ||||
/* Working pointer for state buffer is updated */ | ||||
py = pState; | ||||
/* blockSize samples are read from the state buffer */ | ||||
arm_circularRead_f32((int32_t *) py, delaySize, &readIndex, 1, | ||||
(int32_t *) pb, (int32_t *) pb, blockSize, 1, | ||||
blockSize); | ||||
/* Working pointer for the scratch buffer of state values */ | ||||
px = pb; | ||||
/* Working pointer for scratch buffer of output values */ | ||||
pOut = pDst; | ||||
blkCnt = blockSize; | ||||
while(blkCnt > 0u) | ||||
{ | ||||
/* Perform Multiply-Accumulate */ | ||||
out = *pOut; | ||||
out += ((q63_t) * px++ * coeff) >> 32; | ||||
*pOut++ = (q31_t) (out); | ||||
/* Decrement the loop counter */ | ||||
blkCnt--; | ||||
} | ||||
/* Load the coefficient value and | ||||
* increment the coefficient buffer for the next set of state values */ | ||||
coeff = *pCoeffs++; | ||||
/* Read Index, from where the state buffer should be read, is calculated. */ | ||||
readIndex = (int32_t) (S->stateIndex - blockSize) - *pTapDelay++; | ||||
/* Wraparound of readIndex */ | ||||
if(readIndex < 0) | ||||
{ | ||||
readIndex += (int32_t) delaySize; | ||||
} | ||||
/* Decrement the tap loop counter */ | ||||
tapCnt--; | ||||
} | ||||
/* Working output pointer is updated */ | ||||
pOut = pDst; | ||||
/* Output is converted into 1.31 format. */ | ||||
blkCnt = blockSize; | ||||
while(blkCnt > 0u) | ||||
{ | ||||
in = *pOut << 1; | ||||
*pOut++ = in; | ||||
/* Decrement the loop counter */ | ||||
blkCnt--; | ||||
} | ||||
#endif /* #ifndef ARM_MATH_CM0 */ | ||||
} | ||||
/** | ||||
* @} end of FIR_Sparse group | ||||
*/ | ||||