| /* ---------------------------------------------------------------------- |
| * Copyright (C) 2010-2014 ARM Limited. All rights reserved. |
| * |
| * $Date: 19. March 2015 |
| * $Revision: V.1.4.5 |
| * |
| * Project: CMSIS DSP Library |
| * Title: arm_correlate_fast_q15.c |
| * |
| * Description: Fast Q15 Correlation. |
| * |
| * Target Processor: Cortex-M4/Cortex-M3 |
| * |
| * 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 Corr |
| * @{ |
| */ |
| |
| /** |
| * @brief Correlation of Q15 sequences (fast version) for Cortex-M3 and Cortex-M4. |
| * @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. |
| * |
| * <b>Scaling and Overflow Behavior:</b> |
| * |
| * \par |
| * This fast version uses a 32-bit accumulator with 2.30 format. |
| * The accumulator 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 overflow since a |
| * maximum of min(srcALen, srcBLen) number of additions is carried internally. |
| * The 2.30 accumulator is right shifted by 15 bits and then saturated to 1.15 format to yield the final result. |
| * |
| * \par |
| * See <code>arm_correlate_q15()</code> for a slower implementation of this function which uses a 64-bit accumulator to avoid wrap around distortion. |
| */ |
| |
| void arm_correlate_fast_q15( |
| q15_t * pSrcA, |
| uint32_t srcALen, |
| q15_t * pSrcB, |
| uint32_t srcBLen, |
| q15_t * pDst) |
| { |
| #ifndef UNALIGNED_SUPPORT_DISABLE |
| |
| q15_t *pIn1; /* inputA pointer */ |
| q15_t *pIn2; /* inputB pointer */ |
| q15_t *pOut = pDst; /* output pointer */ |
| q31_t sum, acc0, acc1, acc2, acc3; /* Accumulators */ |
| q15_t *px; /* Intermediate inputA pointer */ |
| q15_t *py; /* Intermediate inputB pointer */ |
| q15_t *pSrc1; /* Intermediate pointers */ |
| 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 loop 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] , x[1] * y[srcBLen - 3] */ |
| sum = __SMLAD(*__SIMD32(px)++, *__SIMD32(py)++, sum); |
| /* x[3] * y[srcBLen - 1] , x[2] * y[srcBLen - 2] */ |
| sum = __SMLAD(*__SIMD32(px)++, *__SIMD32(py)++, sum); |
| |
| /* 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 = __SMLAD(*px++, *py++, sum); |
| |
| /* Decrement the loop counter */ |
| k--; |
| } |
| |
| /* Store the result in the accumulator in the destination buffer. */ |
| *pOut = (q15_t) (sum >> 15); |
| /* 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 = 0u; |
| |
| /* ------------------- |
| * 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, to loop unroll the srcBLen loop */ |
| 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] samples */ |
| x0 = *__SIMD32(px); |
| /* read x[1], x[2] samples */ |
| x1 = _SIMD32_OFFSET(px + 1); |
| px += 2u; |
| |
| /* 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 the first two inputB samples using SIMD: |
| * y[0] and y[1] */ |
| c0 = *__SIMD32(py)++; |
| |
| /* acc0 += x[0] * y[0] + x[1] * y[1] */ |
| acc0 = __SMLAD(x0, c0, acc0); |
| |
| /* acc1 += x[1] * y[0] + x[2] * y[1] */ |
| acc1 = __SMLAD(x1, c0, acc1); |
| |
| /* Read x[2], x[3] */ |
| x2 = *__SIMD32(px); |
| |
| /* Read x[3], x[4] */ |
| x3 = _SIMD32_OFFSET(px + 1); |
| |
| /* acc2 += x[2] * y[0] + x[3] * y[1] */ |
| acc2 = __SMLAD(x2, c0, acc2); |
| |
| /* acc3 += x[3] * y[0] + x[4] * y[1] */ |
| acc3 = __SMLAD(x3, c0, acc3); |
| |
| /* Read y[2] and y[3] */ |
| c0 = *__SIMD32(py)++; |
| |
| /* acc0 += x[2] * y[2] + x[3] * y[3] */ |
| acc0 = __SMLAD(x2, c0, acc0); |
| |
| /* acc1 += x[3] * y[2] + x[4] * y[3] */ |
| acc1 = __SMLAD(x3, c0, acc1); |
| |
| /* Read x[4], x[5] */ |
| x0 = _SIMD32_OFFSET(px + 2); |
| |
| /* Read x[5], x[6] */ |
| x1 = _SIMD32_OFFSET(px + 3); |
| px += 4u; |
| |
| /* acc2 += x[4] * y[2] + x[5] * y[3] */ |
| acc2 = __SMLAD(x0, c0, acc2); |
| |
| /* acc3 += x[5] * y[2] + x[6] * y[3] */ |
| acc3 = __SMLAD(x1, c0, acc3); |
| |
| } while(--k); |
| |
| /* For the next MAC operations, SIMD is not used |
| * So, the 16 bit pointer if inputB, py is updated */ |
| |
| /* If the srcBLen is not a multiple of 4, compute any remaining MACs here. |
| ** No loop unrolling is used. */ |
| k = srcBLen % 0x4u; |
| |
| if(k == 1u) |
| { |
| /* Read y[4] */ |
| c0 = *py; |
| #ifdef ARM_MATH_BIG_ENDIAN |
| |
| c0 = c0 << 16u; |
| |
| #else |
| |
| c0 = c0 & 0x0000FFFF; |
| |
| #endif /* #ifdef ARM_MATH_BIG_ENDIAN */ |
| |
| /* Read x[7] */ |
| x3 = *__SIMD32(px); |
| px++; |
| |
| /* Perform the multiply-accumulates */ |
| acc0 = __SMLAD(x0, c0, acc0); |
| acc1 = __SMLAD(x1, c0, acc1); |
| acc2 = __SMLADX(x1, c0, acc2); |
| acc3 = __SMLADX(x3, c0, acc3); |
| } |
| |
| if(k == 2u) |
| { |
| /* Read y[4], y[5] */ |
| c0 = *__SIMD32(py); |
| |
| /* Read x[7], x[8] */ |
| x3 = *__SIMD32(px); |
| |
| /* Read x[9] */ |
| x2 = _SIMD32_OFFSET(px + 1); |
| px += 2u; |
| |
| /* Perform the multiply-accumulates */ |
| acc0 = __SMLAD(x0, c0, acc0); |
| acc1 = __SMLAD(x1, c0, acc1); |
| acc2 = __SMLAD(x3, c0, acc2); |
| acc3 = __SMLAD(x2, c0, acc3); |
| } |
| |
| if(k == 3u) |
| { |
| /* Read y[4], y[5] */ |
| c0 = *__SIMD32(py)++; |
| |
| /* Read x[7], x[8] */ |
| x3 = *__SIMD32(px); |
| |
| /* Read x[9] */ |
| x2 = _SIMD32_OFFSET(px + 1); |
| |
| /* Perform the multiply-accumulates */ |
| acc0 = __SMLAD(x0, c0, acc0); |
| acc1 = __SMLAD(x1, c0, acc1); |
| acc2 = __SMLAD(x3, c0, acc2); |
| acc3 = __SMLAD(x2, c0, acc3); |
| |
| c0 = (*py); |
| /* Read y[6] */ |
| #ifdef ARM_MATH_BIG_ENDIAN |
| |
| c0 = c0 << 16u; |
| #else |
| |
| c0 = c0 & 0x0000FFFF; |
| #endif /* #ifdef ARM_MATH_BIG_ENDIAN */ |
| |
| /* Read x[10] */ |
| x3 = _SIMD32_OFFSET(px + 2); |
| px += 3u; |
| |
| /* Perform the multiply-accumulates */ |
| acc0 = __SMLADX(x1, c0, acc0); |
| acc1 = __SMLAD(x2, c0, acc1); |
| acc2 = __SMLADX(x2, c0, acc2); |
| acc3 = __SMLADX(x3, c0, acc3); |
| } |
| |
| /* Store the result in the accumulator in the destination buffer. */ |
| *pOut = (q15_t) (acc0 >> 15); |
| /* Destination pointer is updated according to the address modifier, inc */ |
| pOut += inc; |
| |
| *pOut = (q15_t) (acc1 >> 15); |
| pOut += inc; |
| |
| *pOut = (q15_t) (acc2 >> 15); |
| pOut += inc; |
| |
| *pOut = (q15_t) (acc3 >> 15); |
| pOut += inc; |
| |
| /* Increment the pointer pIn1 index, count by 1 */ |
| count += 4u; |
| |
| /* Update the inputA and inputB pointers for next MAC calculation */ |
| px = pIn1 + count; |
| py = pIn2; |
| |
| |
| /* 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 += ((q31_t) * px++ * *py++); |
| sum += ((q31_t) * px++ * *py++); |
| sum += ((q31_t) * px++ * *py++); |
| sum += ((q31_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-accumulates */ |
| sum += ((q31_t) * px++ * *py++); |
| |
| /* Decrement the loop counter */ |
| k--; |
| } |
| |
| /* Store the result in the accumulator in the destination buffer. */ |
| *pOut = (q15_t) (sum >> 15); |
| /* Destination pointer is updated according to the address modifier, inc */ |
| pOut += inc; |
| |
| /* Increment the pointer pIn1 index, count by 1 */ |
| count++; |
| |
| /* Update the inputA and inputB pointers for next MAC calculation */ |
| px = pIn1 + count; |
| py = pIn2; |
| |
| /* 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 += ((q31_t) * px++ * *py++); |
| |
| /* Decrement the loop counter */ |
| k--; |
| } |
| |
| /* Store the result in the accumulator in the destination buffer. */ |
| *pOut = (q15_t) (sum >> 15); |
| /* Destination pointer is updated according to the address modifier, inc */ |
| pOut += inc; |
| |
| /* Increment the MAC count */ |
| count++; |
| |
| /* Update the inputA and inputB pointers for next MAC calculation */ |
| px = pIn1 + count; |
| py = pIn2; |
| |
| /* 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 += x[srcALen - srcBLen + 3] * y[2] */ |
| sum = __SMLAD(*__SIMD32(px)++, *__SIMD32(py)++, sum); |
| /* sum += x[srcALen - srcBLen + 2] * y[1] , sum += x[srcALen - srcBLen + 1] * y[0] */ |
| sum = __SMLAD(*__SIMD32(px)++, *__SIMD32(py)++, sum); |
| |
| /* 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 = __SMLAD(*px++, *py++, sum); |
| |
| /* Decrement the loop counter */ |
| k--; |
| } |
| |
| /* Store the result in the accumulator in the destination buffer. */ |
| *pOut = (q15_t) (sum >> 15); |
| /* 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 |
| |
| q15_t *pIn1; /* inputA pointer */ |
| q15_t *pIn2; /* inputB pointer */ |
| q15_t *pOut = pDst; /* output pointer */ |
| q31_t sum, acc0, acc1, acc2, acc3; /* Accumulators */ |
| q15_t *px; /* Intermediate inputA pointer */ |
| q15_t *py; /* Intermediate inputB pointer */ |
| q15_t *pSrc1; /* Intermediate pointers */ |
| 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 */ |
| q15_t a, b; |
| |
| |
| /* 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 loop 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] , x[1] * y[srcBLen - 3] */ |
| sum += ((q31_t) * px++ * *py++); |
| sum += ((q31_t) * px++ * *py++); |
| sum += ((q31_t) * px++ * *py++); |
| sum += ((q31_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 += ((q31_t) * px++ * *py++); |
| |
| /* Decrement the loop counter */ |
| k--; |
| } |
| |
| /* Store the result in the accumulator in the destination buffer. */ |
| *pOut = (q15_t) (sum >> 15); |
| /* 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 = 0u; |
| |
| /* ------------------- |
| * 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, to loop unroll the srcBLen loop */ |
| 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 */ |
| a = *px; |
| b = *(px + 1); |
| |
| #ifndef ARM_MATH_BIG_ENDIAN |
| |
| x0 = __PKHBT(a, b, 16); |
| a = *(px + 2); |
| x1 = __PKHBT(b, a, 16); |
| |
| #else |
| |
| x0 = __PKHBT(b, a, 16); |
| a = *(px + 2); |
| x1 = __PKHBT(a, b, 16); |
| |
| #endif /* #ifndef ARM_MATH_BIG_ENDIAN */ |
| |
| px += 2u; |
| |
| /* 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 the first two inputB samples using SIMD: |
| * y[0] and y[1] */ |
| a = *py; |
| b = *(py + 1); |
| |
| #ifndef ARM_MATH_BIG_ENDIAN |
| |
| c0 = __PKHBT(a, b, 16); |
| |
| #else |
| |
| c0 = __PKHBT(b, a, 16); |
| |
| #endif /* #ifndef ARM_MATH_BIG_ENDIAN */ |
| |
| /* acc0 += x[0] * y[0] + x[1] * y[1] */ |
| acc0 = __SMLAD(x0, c0, acc0); |
| |
| /* acc1 += x[1] * y[0] + x[2] * y[1] */ |
| acc1 = __SMLAD(x1, c0, acc1); |
| |
| /* Read x[2], x[3], x[4] */ |
| a = *px; |
| b = *(px + 1); |
| |
| #ifndef ARM_MATH_BIG_ENDIAN |
| |
| x2 = __PKHBT(a, b, 16); |
| a = *(px + 2); |
| x3 = __PKHBT(b, a, 16); |
| |
| #else |
| |
| x2 = __PKHBT(b, a, 16); |
| a = *(px + 2); |
| x3 = __PKHBT(a, b, 16); |
| |
| #endif /* #ifndef ARM_MATH_BIG_ENDIAN */ |
| |
| /* acc2 += x[2] * y[0] + x[3] * y[1] */ |
| acc2 = __SMLAD(x2, c0, acc2); |
| |
| /* acc3 += x[3] * y[0] + x[4] * y[1] */ |
| acc3 = __SMLAD(x3, c0, acc3); |
| |
| /* Read y[2] and y[3] */ |
| a = *(py + 2); |
| b = *(py + 3); |
| |
| py += 4u; |
| |
| #ifndef ARM_MATH_BIG_ENDIAN |
| |
| c0 = __PKHBT(a, b, 16); |
| |
| #else |
| |
| c0 = __PKHBT(b, a, 16); |
| |
| #endif /* #ifndef ARM_MATH_BIG_ENDIAN */ |
| |
| /* acc0 += x[2] * y[2] + x[3] * y[3] */ |
| acc0 = __SMLAD(x2, c0, acc0); |
| |
| /* acc1 += x[3] * y[2] + x[4] * y[3] */ |
| acc1 = __SMLAD(x3, c0, acc1); |
| |
| /* Read x[4], x[5], x[6] */ |
| a = *(px + 2); |
| b = *(px + 3); |
| |
| #ifndef ARM_MATH_BIG_ENDIAN |
| |
| x0 = __PKHBT(a, b, 16); |
| a = *(px + 4); |
| x1 = __PKHBT(b, a, 16); |
| |
| #else |
| |
| x0 = __PKHBT(b, a, 16); |
| a = *(px + 4); |
| x1 = __PKHBT(a, b, 16); |
| |
| #endif /* #ifndef ARM_MATH_BIG_ENDIAN */ |
| |
| px += 4u; |
| |
| /* acc2 += x[4] * y[2] + x[5] * y[3] */ |
| acc2 = __SMLAD(x0, c0, acc2); |
| |
| /* acc3 += x[5] * y[2] + x[6] * y[3] */ |
| acc3 = __SMLAD(x1, c0, acc3); |
| |
| } while(--k); |
| |
| /* For the next MAC operations, SIMD is not used |
| * So, the 16 bit pointer if inputB, py is updated */ |
| |
| /* If the srcBLen is not a multiple of 4, compute any remaining MACs here. |
| ** No loop unrolling is used. */ |
| k = srcBLen % 0x4u; |
| |
| if(k == 1u) |
| { |
| /* Read y[4] */ |
| c0 = *py; |
| #ifdef ARM_MATH_BIG_ENDIAN |
| |
| c0 = c0 << 16u; |
| |
| #else |
| |
| c0 = c0 & 0x0000FFFF; |
| |
| #endif /* #ifdef ARM_MATH_BIG_ENDIAN */ |
| |
| /* Read x[7] */ |
| a = *px; |
| b = *(px + 1); |
| |
| px++;; |
| |
| #ifndef ARM_MATH_BIG_ENDIAN |
| |
| x3 = __PKHBT(a, b, 16); |
| |
| #else |
| |
| x3 = __PKHBT(b, a, 16); |
| |
| #endif /* #ifndef ARM_MATH_BIG_ENDIAN */ |
| |
| px++; |
| |
| /* Perform the multiply-accumulates */ |
| acc0 = __SMLAD(x0, c0, acc0); |
| acc1 = __SMLAD(x1, c0, acc1); |
| acc2 = __SMLADX(x1, c0, acc2); |
| acc3 = __SMLADX(x3, c0, acc3); |
| } |
| |
| if(k == 2u) |
| { |
| /* Read y[4], y[5] */ |
| a = *py; |
| b = *(py + 1); |
| |
| #ifndef ARM_MATH_BIG_ENDIAN |
| |
| c0 = __PKHBT(a, b, 16); |
| |
| #else |
| |
| c0 = __PKHBT(b, a, 16); |
| |
| #endif /* #ifndef ARM_MATH_BIG_ENDIAN */ |
| |
| /* Read x[7], x[8], x[9] */ |
| a = *px; |
| b = *(px + 1); |
| |
| #ifndef ARM_MATH_BIG_ENDIAN |
| |
| x3 = __PKHBT(a, b, 16); |
| a = *(px + 2); |
| x2 = __PKHBT(b, a, 16); |
| |
| #else |
| |
| x3 = __PKHBT(b, a, 16); |
| a = *(px + 2); |
| x2 = __PKHBT(a, b, 16); |
| |
| #endif /* #ifndef ARM_MATH_BIG_ENDIAN */ |
| |
| px += 2u; |
| |
| /* Perform the multiply-accumulates */ |
| acc0 = __SMLAD(x0, c0, acc0); |
| acc1 = __SMLAD(x1, c0, acc1); |
| acc2 = __SMLAD(x3, c0, acc2); |
| acc3 = __SMLAD(x2, c0, acc3); |
| } |
| |
| if(k == 3u) |
| { |
| /* Read y[4], y[5] */ |
| a = *py; |
| b = *(py + 1); |
| |
| #ifndef ARM_MATH_BIG_ENDIAN |
| |
| c0 = __PKHBT(a, b, 16); |
| |
| #else |
| |
| c0 = __PKHBT(b, a, 16); |
| |
| #endif /* #ifndef ARM_MATH_BIG_ENDIAN */ |
| |
| py += 2u; |
| |
| /* Read x[7], x[8], x[9] */ |
| a = *px; |
| b = *(px + 1); |
| |
| #ifndef ARM_MATH_BIG_ENDIAN |
| |
| x3 = __PKHBT(a, b, 16); |
| a = *(px + 2); |
| x2 = __PKHBT(b, a, 16); |
| |
| #else |
| |
| x3 = __PKHBT(b, a, 16); |
| a = *(px + 2); |
| x2 = __PKHBT(a, b, 16); |
| |
| #endif /* #ifndef ARM_MATH_BIG_ENDIAN */ |
| |
| /* Perform the multiply-accumulates */ |
| acc0 = __SMLAD(x0, c0, acc0); |
| acc1 = __SMLAD(x1, c0, acc1); |
| acc2 = __SMLAD(x3, c0, acc2); |
| acc3 = __SMLAD(x2, c0, acc3); |
| |
| c0 = (*py); |
| /* Read y[6] */ |
| #ifdef ARM_MATH_BIG_ENDIAN |
| |
| c0 = c0 << 16u; |
| #else |
| |
| c0 = c0 & 0x0000FFFF; |
| #endif /* #ifdef ARM_MATH_BIG_ENDIAN */ |
| |
| /* Read x[10] */ |
| b = *(px + 3); |
| |
| #ifndef ARM_MATH_BIG_ENDIAN |
| |
| x3 = __PKHBT(a, b, 16); |
| |
| #else |
| |
| x3 = __PKHBT(b, a, 16); |
| |
| #endif /* #ifndef ARM_MATH_BIG_ENDIAN */ |
| |
| px += 3u; |
| |
| /* Perform the multiply-accumulates */ |
| acc0 = __SMLADX(x1, c0, acc0); |
| acc1 = __SMLAD(x2, c0, acc1); |
| acc2 = __SMLADX(x2, c0, acc2); |
| acc3 = __SMLADX(x3, c0, acc3); |
| } |
| |
| /* Store the result in the accumulator in the destination buffer. */ |
| *pOut = (q15_t) (acc0 >> 15); |
| /* Destination pointer is updated according to the address modifier, inc */ |
| pOut += inc; |
| |
| *pOut = (q15_t) (acc1 >> 15); |
| pOut += inc; |
| |
| *pOut = (q15_t) (acc2 >> 15); |
| pOut += inc; |
| |
| *pOut = (q15_t) (acc3 >> 15); |
| pOut += inc; |
| |
| /* Increment the pointer pIn1 index, count by 1 */ |
| count += 4u; |
| |
| /* Update the inputA and inputB pointers for next MAC calculation */ |
| px = pIn1 + count; |
| py = pIn2; |
| |
| |
| /* 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 += ((q31_t) * px++ * *py++); |
| sum += ((q31_t) * px++ * *py++); |
| sum += ((q31_t) * px++ * *py++); |
| sum += ((q31_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-accumulates */ |
| sum += ((q31_t) * px++ * *py++); |
| |
| /* Decrement the loop counter */ |
| k--; |
| } |
| |
| /* Store the result in the accumulator in the destination buffer. */ |
| *pOut = (q15_t) (sum >> 15); |
| /* Destination pointer is updated according to the address modifier, inc */ |
| pOut += inc; |
| |
| /* Increment the pointer pIn1 index, count by 1 */ |
| count++; |
| |
| /* Update the inputA and inputB pointers for next MAC calculation */ |
| px = pIn1 + count; |
| py = pIn2; |
| |
| /* 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 += ((q31_t) * px++ * *py++); |
| |
| /* Decrement the loop counter */ |
| k--; |
| } |
| |
| /* Store the result in the accumulator in the destination buffer. */ |
| *pOut = (q15_t) (sum >> 15); |
| /* Destination pointer is updated according to the address modifier, inc */ |
| pOut += inc; |
| |
| /* Increment the MAC count */ |
| count++; |
| |
| /* Update the inputA and inputB pointers for next MAC calculation */ |
| px = pIn1 + count; |
| py = pIn2; |
| |
| /* 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 += ((q31_t) * px++ * *py++); |
| sum += ((q31_t) * px++ * *py++); |
| sum += ((q31_t) * px++ * *py++); |
| sum += ((q31_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 += ((q31_t) * px++ * *py++); |
| |
| /* Decrement the loop counter */ |
| k--; |
| } |
| |
| /* Store the result in the accumulator in the destination buffer. */ |
| *pOut = (q15_t) (sum >> 15); |
| /* 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--; |
| } |
| |
| #endif /* #ifndef UNALIGNED_SUPPORT_DISABLE */ |
| |
| } |
| |
| /** |
| * @} end of Corr group |
| */ |
