+++ /dev/null
-/* ----------------------------------------------------------------------
-* Copyright (C) 2010 ARM Limited. All rights reserved.
-*
-* $Date: 15. July 2011
-* $Revision: V1.0.10
-*
-* Project: CMSIS DSP Library
-* Title: arm_correlate_q31.c
-*
-* Description: Correlation of Q31 sequences.
-*
-* 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"
-
-/**
- * @ingroup groupFilters
- */
-
-/**
- * @addtogroup Corr
- * @{
- */
-
-/**
- * @brief Correlation of Q31 sequences.
- * @param[in] *pSrcA points to the first input sequence.
- * @param[in] srcALen length of the first input sequence.
- * @param[in] *pSrcB points to the second input sequence.
- * @param[in] srcBLen length of the second input sequence.
- * @param[out] *pDst points to the location where the output result is written. Length 2 * max(srcALen, srcBLen) - 1.
- * @return none.
- *
- * @details
- * <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.
- * There is no saturation on intermediate additions.
- * Thus, if the accumulator overflows it wraps around and distorts the result.
- * The input signals should be scaled down to avoid intermediate overflows.
- * Scale down one of the inputs by 1/min(srcALen, srcBLen)to avoid overflows since a
- * maximum of min(srcALen, srcBLen) number of additions is carried internally.
- * The 2.62 accumulator is right shifted by 31 bits and saturated to 1.31 format to yield the final result.
- *
- * \par
- * See <code>arm_correlate_fast_q31()</code> for a faster but less precise implementation of this function for Cortex-M3 and Cortex-M4.
- */
-
-void arm_correlate_q31(
- q31_t * pSrcA,
- uint32_t srcALen,
- q31_t * pSrcB,
- uint32_t srcBLen,
- q31_t * pDst)
-{
-
-#ifndef ARM_MATH_CM0
-
- /* Run the below code for Cortex-M4 and Cortex-M3 */
-
- q31_t *pIn1; /* inputA pointer */
- q31_t *pIn2; /* inputB pointer */
- q31_t *pOut = pDst; /* output pointer */
- q31_t *px; /* Intermediate inputA pointer */
- q31_t *py; /* Intermediate inputB pointer */
- q31_t *pSrc1; /* Intermediate pointers */
- q63_t sum, acc0, acc1, acc2, acc3; /* Accumulators */
- q31_t x0, x1, x2, x3, c0; /* temporary variables for holding input and coefficient values */
- uint32_t j, k = 0u, count, blkCnt, outBlockSize, blockSize1, blockSize2, blockSize3; /* loop counter */
- int32_t inc = 1; /* Destination address modifier */
-
-
- /* The algorithm implementation is based on the lengths of the inputs. */
- /* srcB is always made to slide across srcA. */
- /* So srcBLen is always considered as shorter or equal to srcALen */
- /* But CORR(x, y) is reverse of CORR(y, x) */
- /* So, when srcBLen > srcALen, output pointer is made to point to the end of the output buffer */
- /* and the destination pointer modifier, inc is set to -1 */
- /* If srcALen > srcBLen, zero pad has to be done to srcB to make the two inputs of same length */
- /* But to improve the performance,
- * we include zeroes in the output instead of zero padding either of the the inputs*/
- /* If srcALen > srcBLen,
- * (srcALen - srcBLen) zeroes has to included in the starting of the output buffer */
- /* If srcALen < srcBLen,
- * (srcALen - srcBLen) zeroes has to included in the ending of the output buffer */
- if(srcALen >= srcBLen)
- {
- /* Initialization of inputA pointer */
- pIn1 = (pSrcA);
-
- /* Initialization of inputB pointer */
- pIn2 = (pSrcB);
-
- /* Number of output samples is calculated */
- outBlockSize = (2u * srcALen) - 1u;
-
- /* When srcALen > srcBLen, zero padding is done to srcB
- * to make their lengths equal.
- * Instead, (outBlockSize - (srcALen + srcBLen - 1))
- * number of output samples are made zero */
- j = outBlockSize - (srcALen + (srcBLen - 1u));
-
- /* Updating the pointer position to non zero value */
- pOut += j;
-
- }
- else
- {
- /* Initialization of inputA pointer */
- pIn1 = (pSrcB);
-
- /* Initialization of inputB pointer */
- pIn2 = (pSrcA);
-
- /* srcBLen is always considered as shorter or equal to srcALen */
- j = srcBLen;
- srcBLen = srcALen;
- srcALen = j;
-
- /* CORR(x, y) = Reverse order(CORR(y, x)) */
- /* Hence set the destination pointer to point to the last output sample */
- pOut = pDst + ((srcALen + srcBLen) - 2u);
-
- /* Destination address modifier is set to -1 */
- inc = -1;
-
- }
-
- /* The function is internally
- * divided into three parts according to the number of multiplications that has to be
- * taken place between inputA samples and inputB samples. In the first part of the
- * algorithm, the multiplications increase by one for every iteration.
- * In the second part of the algorithm, srcBLen number of multiplications are done.
- * In the third part of the algorithm, the multiplications decrease by one
- * for every iteration.*/
- /* The algorithm is implemented in three stages.
- * The loop counters of each stage is initiated here. */
- blockSize1 = srcBLen - 1u;
- blockSize2 = srcALen - (srcBLen - 1u);
- blockSize3 = blockSize1;
-
- /* --------------------------
- * Initializations of stage1
- * -------------------------*/
-
- /* sum = x[0] * y[srcBlen - 1]
- * sum = x[0] * y[srcBlen - 2] + x[1] * y[srcBlen - 1]
- * ....
- * sum = x[0] * y[0] + x[1] * y[1] +...+ x[srcBLen - 1] * y[srcBLen - 1]
- */
-
- /* In this stage the MAC operations are increased by 1 for every iteration.
- The count variable holds the number of MAC operations performed */
- count = 1u;
-
- /* Working pointer of inputA */
- px = pIn1;
-
- /* Working pointer of inputB */
- pSrc1 = pIn2 + (srcBLen - 1u);
- py = pSrc1;
-
- /* ------------------------
- * Stage1 process
- * ----------------------*/
-
- /* The first stage starts here */
- while(blockSize1 > 0u)
- {
- /* Accumulator is made zero for every iteration */
- sum = 0;
-
- /* Apply loop unrolling and compute 4 MACs simultaneously. */
- k = count >> 2;
-
- /* First part of the processing with loop unrolling. Compute 4 MACs at a time.
- ** a second loop below computes MACs for the remaining 1 to 3 samples. */
- while(k > 0u)
- {
- /* x[0] * y[srcBLen - 4] */
- sum += (q63_t) * px++ * (*py++);
- /* x[1] * y[srcBLen - 3] */
- sum += (q63_t) * px++ * (*py++);
- /* x[2] * y[srcBLen - 2] */
- sum += (q63_t) * px++ * (*py++);
- /* x[3] * y[srcBLen - 1] */
- sum += (q63_t) * px++ * (*py++);
-
- /* Decrement the loop counter */
- k--;
- }
-
- /* If the count is not a multiple of 4, compute any remaining MACs here.
- ** No loop unrolling is used. */
- k = count % 0x4u;
-
- while(k > 0u)
- {
- /* Perform the multiply-accumulates */
- /* x[0] * y[srcBLen - 1] */
- sum += (q63_t) * px++ * (*py++);
-
- /* Decrement the loop counter */
- k--;
- }
-
- /* Store the result in the accumulator in the destination buffer. */
- *pOut = (q31_t) (sum >> 31);
- /* Destination pointer is updated according to the address modifier, inc */
- pOut += inc;
-
- /* Update the inputA and inputB pointers for next MAC calculation */
- py = pSrc1 - count;
- px = pIn1;
-
- /* Increment the MAC count */
- count++;
-
- /* Decrement the loop counter */
- blockSize1--;
- }
-
- /* --------------------------
- * Initializations of stage2
- * ------------------------*/
-
- /* sum = x[0] * y[0] + x[1] * y[1] +...+ x[srcBLen-1] * y[srcBLen-1]
- * sum = x[1] * y[0] + x[2] * y[1] +...+ x[srcBLen] * y[srcBLen-1]
- * ....
- * sum = x[srcALen-srcBLen-2] * y[0] + x[srcALen-srcBLen-1] * y[1] +...+ x[srcALen-1] * y[srcBLen-1]
- */
-
- /* Working pointer of inputA */
- px = pIn1;
-
- /* Working pointer of inputB */
- py = pIn2;
-
- /* count is index by which the pointer pIn1 to be incremented */
- count = 1u;
-
- /* -------------------
- * Stage2 process
- * ------------------*/
-
- /* Stage2 depends on srcBLen as in this stage srcBLen number of MACS are performed.
- * So, to loop unroll over blockSize2,
- * srcBLen should be greater than or equal to 4 */
- if(srcBLen >= 4u)
- {
- /* Loop unroll over blockSize2, by 4 */
- blkCnt = blockSize2 >> 2u;
-
- while(blkCnt > 0u)
- {
- /* Set all accumulators to zero */
- acc0 = 0;
- acc1 = 0;
- acc2 = 0;
- acc3 = 0;
-
- /* read x[0], x[1], x[2] samples */
- x0 = *(px++);
- x1 = *(px++);
- x2 = *(px++);
-
- /* Apply loop unrolling and compute 4 MACs simultaneously. */
- k = srcBLen >> 2u;
-
- /* First part of the processing with loop unrolling. Compute 4 MACs at a time.
- ** a second loop below computes MACs for the remaining 1 to 3 samples. */
- do
- {
- /* Read y[0] sample */
- c0 = *(py++);
-
- /* Read x[3] sample */
- x3 = *(px++);
-
- /* Perform the multiply-accumulate */
- /* acc0 += x[0] * y[0] */
- acc0 += ((q63_t) x0 * c0);
- /* acc1 += x[1] * y[0] */
- acc1 += ((q63_t) x1 * c0);
- /* acc2 += x[2] * y[0] */
- acc2 += ((q63_t) x2 * c0);
- /* acc3 += x[3] * y[0] */
- acc3 += ((q63_t) x3 * c0);
-
- /* Read y[1] sample */
- c0 = *(py++);
-
- /* Read x[4] sample */
- x0 = *(px++);
-
- /* Perform the multiply-accumulates */
- /* acc0 += x[1] * y[1] */
- acc0 += ((q63_t) x1 * c0);
- /* acc1 += x[2] * y[1] */
- acc1 += ((q63_t) x2 * c0);
- /* acc2 += x[3] * y[1] */
- acc2 += ((q63_t) x3 * c0);
- /* acc3 += x[4] * y[1] */
- acc3 += ((q63_t) x0 * c0);
- /* Read y[2] sample */
- c0 = *(py++);
-
- /* Read x[5] sample */
- x1 = *(px++);
-
- /* Perform the multiply-accumulates */
- /* acc0 += x[2] * y[2] */
- acc0 += ((q63_t) x2 * c0);
- /* acc1 += x[3] * y[2] */
- acc1 += ((q63_t) x3 * c0);
- /* acc2 += x[4] * y[2] */
- acc2 += ((q63_t) x0 * c0);
- /* acc3 += x[5] * y[2] */
- acc3 += ((q63_t) x1 * c0);
-
- /* Read y[3] sample */
- c0 = *(py++);
-
- /* Read x[6] sample */
- x2 = *(px++);
-
- /* Perform the multiply-accumulates */
- /* acc0 += x[3] * y[3] */
- acc0 += ((q63_t) x3 * c0);
- /* acc1 += x[4] * y[3] */
- acc1 += ((q63_t) x0 * c0);
- /* acc2 += x[5] * y[3] */
- acc2 += ((q63_t) x1 * c0);
- /* acc3 += x[6] * y[3] */
- acc3 += ((q63_t) x2 * c0);
-
-
- } while(--k);
-
- /* If the srcBLen is not a multiple of 4, compute any remaining MACs here.
- ** No loop unrolling is used. */
- k = srcBLen % 0x4u;
-
- while(k > 0u)
- {
- /* Read y[4] sample */
- c0 = *(py++);
-
- /* Read x[7] sample */
- x3 = *(px++);
-
- /* Perform the multiply-accumulates */
- /* acc0 += x[4] * y[4] */
- acc0 += ((q63_t) x0 * c0);
- /* acc1 += x[5] * y[4] */
- acc1 += ((q63_t) x1 * c0);
- /* acc2 += x[6] * y[4] */
- acc2 += ((q63_t) x2 * c0);
- /* acc3 += x[7] * y[4] */
- acc3 += ((q63_t) x3 * c0);
-
- /* Reuse the present samples for the next MAC */
- x0 = x1;
- x1 = x2;
- x2 = x3;
-
- /* Decrement the loop counter */
- k--;
- }
-
- /* Store the result in the accumulator in the destination buffer. */
- *pOut = (q31_t) (acc0 >> 31);
- /* Destination pointer is updated according to the address modifier, inc */
- pOut += inc;
-
- *pOut = (q31_t) (acc1 >> 31);
- pOut += inc;
-
- *pOut = (q31_t) (acc2 >> 31);
- pOut += inc;
-
- *pOut = (q31_t) (acc3 >> 31);
- pOut += inc;
-
- /* Update the inputA and inputB pointers for next MAC calculation */
- px = pIn1 + (count * 4u);
- py = pIn2;
-
- /* Increment the pointer pIn1 index, count by 1 */
- count++;
-
- /* Decrement the loop counter */
- blkCnt--;
- }
-
- /* If the blockSize2 is not a multiple of 4, compute any remaining output samples here.
- ** No loop unrolling is used. */
- blkCnt = blockSize2 % 0x4u;
-
- while(blkCnt > 0u)
- {
- /* Accumulator is made zero for every iteration */
- sum = 0;
-
- /* Apply loop unrolling and compute 4 MACs simultaneously. */
- k = srcBLen >> 2u;
-
- /* First part of the processing with loop unrolling. Compute 4 MACs at a time.
- ** a second loop below computes MACs for the remaining 1 to 3 samples. */
- while(k > 0u)
- {
- /* Perform the multiply-accumulates */
- sum += (q63_t) * px++ * (*py++);
- sum += (q63_t) * px++ * (*py++);
- sum += (q63_t) * px++ * (*py++);
- sum += (q63_t) * px++ * (*py++);
-
- /* Decrement the loop counter */
- k--;
- }
-
- /* If the srcBLen is not a multiple of 4, compute any remaining MACs here.
- ** No loop unrolling is used. */
- k = srcBLen % 0x4u;
-
- while(k > 0u)
- {
- /* Perform the multiply-accumulate */
- sum += (q63_t) * px++ * (*py++);
-
- /* Decrement the loop counter */
- k--;
- }
-
- /* Store the result in the accumulator in the destination buffer. */
- *pOut = (q31_t) (sum >> 31);
- /* Destination pointer is updated according to the address modifier, inc */
- pOut += inc;
-
- /* Update the inputA and inputB pointers for next MAC calculation */
- px = pIn1 + count;
- py = pIn2;
-
- /* Increment the MAC count */
- count++;
-
- /* Decrement the loop counter */
- blkCnt--;
- }
- }
- else
- {
- /* If the srcBLen is not a multiple of 4,
- * the blockSize2 loop cannot be unrolled by 4 */
- blkCnt = blockSize2;
-
- while(blkCnt > 0u)
- {
- /* Accumulator is made zero for every iteration */
- sum = 0;
-
- /* Loop over srcBLen */
- k = srcBLen;
-
- while(k > 0u)
- {
- /* Perform the multiply-accumulate */
- sum += (q63_t) * px++ * (*py++);
-
- /* Decrement the loop counter */
- k--;
- }
-
- /* Store the result in the accumulator in the destination buffer. */
- *pOut = (q31_t) (sum >> 31);
- /* Destination pointer is updated according to the address modifier, inc */
- pOut += inc;
-
- /* Update the inputA and inputB pointers for next MAC calculation */
- px = pIn1 + count;
- py = pIn2;
-
- /* Increment the MAC count */
- count++;
-
- /* Decrement the loop counter */
- blkCnt--;
- }
- }
-
- /* --------------------------
- * Initializations of stage3
- * -------------------------*/
-
- /* sum += x[srcALen-srcBLen+1] * y[0] + x[srcALen-srcBLen+2] * y[1] +...+ x[srcALen-1] * y[srcBLen-1]
- * sum += x[srcALen-srcBLen+2] * y[0] + x[srcALen-srcBLen+3] * y[1] +...+ x[srcALen-1] * y[srcBLen-1]
- * ....
- * sum += x[srcALen-2] * y[0] + x[srcALen-1] * y[1]
- * sum += x[srcALen-1] * y[0]
- */
-
- /* In this stage the MAC operations are decreased by 1 for every iteration.
- The count variable holds the number of MAC operations performed */
- count = srcBLen - 1u;
-
- /* Working pointer of inputA */
- pSrc1 = pIn1 + (srcALen - (srcBLen - 1u));
- px = pSrc1;
-
- /* Working pointer of inputB */
- py = pIn2;
-
- /* -------------------
- * Stage3 process
- * ------------------*/
-
- while(blockSize3 > 0u)
- {
- /* Accumulator is made zero for every iteration */
- sum = 0;
-
- /* Apply loop unrolling and compute 4 MACs simultaneously. */
- k = count >> 2u;
-
- /* First part of the processing with loop unrolling. Compute 4 MACs at a time.
- ** a second loop below computes MACs for the remaining 1 to 3 samples. */
- while(k > 0u)
- {
- /* Perform the multiply-accumulates */
- /* sum += x[srcALen - srcBLen + 4] * y[3] */
- sum += (q63_t) * px++ * (*py++);
- /* sum += x[srcALen - srcBLen + 3] * y[2] */
- sum += (q63_t) * px++ * (*py++);
- /* sum += x[srcALen - srcBLen + 2] * y[1] */
- sum += (q63_t) * px++ * (*py++);
- /* sum += x[srcALen - srcBLen + 1] * y[0] */
- sum += (q63_t) * px++ * (*py++);
-
- /* Decrement the loop counter */
- k--;
- }
-
- /* If the count is not a multiple of 4, compute any remaining MACs here.
- ** No loop unrolling is used. */
- k = count % 0x4u;
-
- while(k > 0u)
- {
- /* Perform the multiply-accumulates */
- sum += (q63_t) * px++ * (*py++);
-
- /* Decrement the loop counter */
- k--;
- }
-
- /* Store the result in the accumulator in the destination buffer. */
- *pOut = (q31_t) (sum >> 31);
- /* Destination pointer is updated according to the address modifier, inc */
- pOut += inc;
-
- /* Update the inputA and inputB pointers for next MAC calculation */
- px = ++pSrc1;
- py = pIn2;
-
- /* Decrement the MAC count */
- count--;
-
- /* Decrement the loop counter */
- blockSize3--;
- }
-
-#else
-
- /* Run the below code for Cortex-M0 */
-
- q31_t *pIn1 = pSrcA; /* inputA pointer */
- q31_t *pIn2 = pSrcB + (srcBLen - 1u); /* inputB pointer */
- q63_t sum; /* Accumulators */
- uint32_t i = 0u, j; /* loop counters */
- uint32_t inv = 0u; /* Reverse order flag */
- uint32_t tot = 0u; /* Length */
-
- /* The algorithm implementation is based on the lengths of the inputs. */
- /* srcB is always made to slide across srcA. */
- /* So srcBLen is always considered as shorter or equal to srcALen */
- /* But CORR(x, y) is reverse of CORR(y, x) */
- /* So, when srcBLen > srcALen, output pointer is made to point to the end of the output buffer */
- /* and a varaible, inv is set to 1 */
- /* If lengths are not equal then zero pad has to be done to make the two
- * inputs of same length. But to improve the performance, we include zeroes
- * in the output instead of zero padding either of the the inputs*/
- /* If srcALen > srcBLen, (srcALen - srcBLen) zeroes has to included in the
- * starting of the output buffer */
- /* If srcALen < srcBLen, (srcALen - srcBLen) zeroes has to included in the
- * ending of the output buffer */
- /* Once the zero padding is done the remaining of the output is calcualted
- * using convolution but with the shorter signal time shifted. */
-
- /* Calculate the length of the remaining sequence */
- tot = ((srcALen + srcBLen) - 2u);
-
- if(srcALen > srcBLen)
- {
- /* Calculating the number of zeros to be padded to the output */
- j = srcALen - srcBLen;
-
- /* Initialise the pointer after zero padding */
- pDst += j;
- }
-
- else if(srcALen < srcBLen)
- {
- /* Initialization to inputB pointer */
- pIn1 = pSrcB;
-
- /* Initialization to the end of inputA pointer */
- pIn2 = pSrcA + (srcALen - 1u);
-
- /* Initialisation of the pointer after zero padding */
- pDst = pDst + tot;
-
- /* Swapping the lengths */
- j = srcALen;
- srcALen = srcBLen;
- srcBLen = j;
-
- /* Setting the reverse flag */
- inv = 1;
-
- }
-
- /* Loop to calculate convolution for output length number of times */
- for (i = 0u; i <= tot; i++)
- {
- /* Initialize sum with zero to carry on MAC operations */
- sum = 0;
-
- /* Loop to perform MAC operations according to convolution equation */
- for (j = 0u; j <= i; j++)
- {
- /* Check the array limitations */
- if((((i - j) < srcBLen) && (j < srcALen)))
- {
- /* z[i] += x[i-j] * y[j] */
- sum += ((q63_t) pIn1[j] * pIn2[-((int32_t) i - j)]);
- }
- }
- /* Store the output in the destination buffer */
- if(inv == 1)
- *pDst-- = (q31_t) (sum >> 31u);
- else
- *pDst++ = (q31_t) (sum >> 31u);
- }
-
-#endif /* #ifndef ARM_MATH_CM0 */
-
-}
-
-/**
- * @} end of Corr group
- */
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