123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279280281282283284285286287288289290291292293294295296297298299300301302303304305306307308309310311312313314315316317318319320321322323324325326327328329330331332333334335336337338339340341342343344345346347348349350351352353354355356357358359360361362363364365366367368369370371372373374375376377378379380381382383384385386387388389390391392393394395396397398399400401402403404405406407408409410411412413414415416417418419420421422423424425426427428429430431432433434435436437438439440441442443444445446447448449450451452453454455456457458459460461462463464465466467468469470471472473474475476477478479480481482483484485486487488489490491492493494495496497498499500501502503504505506507508509510511512513514515516517518519520521522523524525526527528529530531532533534535536537538539540541542543544545546547548549550551552553554555556557558559560561562563564565 |
- /* ----------------------------------------------------------------------
- * Copyright (C) 2010-2013 ARM Limited. All rights reserved.
- *
- * $Date: 17. January 2013
- * $Revision: V1.4.1
- *
- * Project: CMSIS DSP Library
- * Title: arm_conv_q31.c
- *
- * Description: Convolution of Q31 sequences.
- *
- * 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 Conv
- * @{
- */
-
- /**
- * @brief Convolution 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 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 the inputs by log2(min(srcALen, srcBLen)) (log2 is read as log to the base 2) times to avoid overflows,
- * as maximum of min(srcALen, srcBLen) number of additions are 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_conv_fast_q31()</code> for a faster but less precise implementation of this function for Cortex-M3 and Cortex-M4.
- */
-
- void arm_conv_q31(
- q31_t * pSrcA,
- uint32_t srcALen,
- q31_t * pSrcB,
- uint32_t srcBLen,
- q31_t * pDst)
- {
-
-
- #ifndef ARM_MATH_CM0_FAMILY
-
- /* 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, *pSrc2; /* Intermediate pointers */
- q63_t sum; /* Accumulator */
- q63_t acc0, acc1, acc2; /* Accumulator */
- q31_t x0, x1, x2, c0; /* Temporary variables to hold state and coefficient values */
- uint32_t j, k, count, blkCnt, blockSize1, blockSize2, blockSize3; /* loop counter */
-
- /* 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 */
- if(srcALen >= srcBLen)
- {
- /* Initialization of inputA pointer */
- pIn1 = pSrcA;
-
- /* Initialization of inputB pointer */
- pIn2 = pSrcB;
- }
- else
- {
- /* Initialization of inputA pointer */
- pIn1 = (q31_t *) pSrcB;
-
- /* Initialization of inputB pointer */
- pIn2 = (q31_t *) pSrcA;
-
- /* srcBLen is always considered as shorter or equal to srcALen */
- j = srcBLen;
- srcBLen = srcALen;
- srcALen = j;
- }
-
- /* conv(x,y) at n = x[n] * y[0] + x[n-1] * y[1] + x[n-2] * y[2] + ...+ x[n-N+1] * y[N -1] */
- /* The function is internally
- * divided into three stages according to the number of multiplications that has to be
- * taken place between inputA samples and inputB samples. In the first stage of the
- * algorithm, the multiplications increase by one for every iteration.
- * In the second stage of the algorithm, srcBLen number of multiplications are done.
- * In the third stage 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[0]
- * sum = x[0] * y[1] + x[1] * y[0]
- * ....
- * sum = x[0] * y[srcBlen - 1] + x[1] * y[srcBlen - 2] +...+ x[srcBLen - 1] * y[0]
- */
-
- /* 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 */
- py = pIn2;
-
-
- /* ------------------------
- * 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 >> 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)
- {
- /* x[0] * y[srcBLen - 1] */
- sum += (q63_t) * px++ * (*py--);
- /* x[1] * y[srcBLen - 2] */
- sum += (q63_t) * px++ * (*py--);
- /* x[2] * y[srcBLen - 3] */
- sum += (q63_t) * px++ * (*py--);
- /* x[3] * y[srcBLen - 4] */
- 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-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);
-
- /* Update the inputA and inputB pointers for next MAC calculation */
- py = pIn2 + count;
- px = pIn1;
-
- /* Increment the MAC count */
- count++;
-
- /* Decrement the loop counter */
- blockSize1--;
- }
-
- /* --------------------------
- * Initializations of stage2
- * ------------------------*/
-
- /* sum = x[0] * y[srcBLen-1] + x[1] * y[srcBLen-2] +...+ x[srcBLen-1] * y[0]
- * sum = x[1] * y[srcBLen-1] + x[2] * y[srcBLen-2] +...+ x[srcBLen] * y[0]
- * ....
- * sum = x[srcALen-srcBLen-2] * y[srcBLen-1] + x[srcALen] * y[srcBLen-2] +...+ x[srcALen-1] * y[0]
- */
-
- /* Working pointer of inputA */
- px = pIn1;
-
- /* Working pointer of inputB */
- pSrc2 = pIn2 + (srcBLen - 1u);
- py = pSrc2;
-
- /* 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 */
- if(srcBLen >= 4u)
- {
- /* Loop unroll by 3 */
- blkCnt = blockSize2 / 3;
-
- while(blkCnt > 0u)
- {
- /* Set all accumulators to zero */
- acc0 = 0;
- acc1 = 0;
- acc2 = 0;
-
- /* read x[0], x[1], x[2] samples */
- x0 = *(px++);
- x1 = *(px++);
-
- /* Apply loop unrolling and compute 3 MACs simultaneously. */
- k = srcBLen / 3;
-
- /* First part of the processing with loop unrolling. Compute 3 MACs at a time.
- ** a second loop below computes MACs for the remaining 1 to 2 samples. */
- do
- {
- /* Read y[srcBLen - 1] sample */
- c0 = *(py);
-
- /* Read x[3] sample */
- x2 = *(px);
-
- /* Perform the multiply-accumulates */
- /* acc0 += x[0] * y[srcBLen - 1] */
- acc0 += ((q63_t) x0 * c0);
- /* acc1 += x[1] * y[srcBLen - 1] */
- acc1 += ((q63_t) x1 * c0);
- /* acc2 += x[2] * y[srcBLen - 1] */
- acc2 += ((q63_t) x2 * c0);
-
- /* Read y[srcBLen - 2] sample */
- c0 = *(py - 1u);
-
- /* Read x[4] sample */
- x0 = *(px + 1u);
-
- /* Perform the multiply-accumulate */
- /* acc0 += x[1] * y[srcBLen - 2] */
- acc0 += ((q63_t) x1 * c0);
- /* acc1 += x[2] * y[srcBLen - 2] */
- acc1 += ((q63_t) x2 * c0);
- /* acc2 += x[3] * y[srcBLen - 2] */
- acc2 += ((q63_t) x0 * c0);
-
- /* Read y[srcBLen - 3] sample */
- c0 = *(py - 2u);
-
- /* Read x[5] sample */
- x1 = *(px + 2u);
-
- /* Perform the multiply-accumulates */
- /* acc0 += x[2] * y[srcBLen - 3] */
- acc0 += ((q63_t) x2 * c0);
- /* acc1 += x[3] * y[srcBLen - 2] */
- acc1 += ((q63_t) x0 * c0);
- /* acc2 += x[4] * y[srcBLen - 2] */
- acc2 += ((q63_t) x1 * c0);
-
- /* update scratch pointers */
- px += 3u;
- py -= 3u;
-
- } while(--k);
-
- /* If the srcBLen is not a multiple of 3, compute any remaining MACs here.
- ** No loop unrolling is used. */
- k = srcBLen - (3 * (srcBLen / 3));
-
- while(k > 0u)
- {
- /* Read y[srcBLen - 5] sample */
- c0 = *(py--);
-
- /* Read x[7] sample */
- x2 = *(px++);
-
- /* Perform the multiply-accumulates */
- /* acc0 += x[4] * y[srcBLen - 5] */
- acc0 += ((q63_t) x0 * c0);
- /* acc1 += x[5] * y[srcBLen - 5] */
- acc1 += ((q63_t) x1 * c0);
- /* acc2 += x[6] * y[srcBLen - 5] */
- acc2 += ((q63_t) x2 * c0);
-
- /* Reuse the present samples for the next MAC */
- x0 = x1;
- x1 = x2;
-
- /* Decrement the loop counter */
- k--;
- }
-
- /* Store the results in the accumulators in the destination buffer. */
- *pOut++ = (q31_t) (acc0 >> 31);
- *pOut++ = (q31_t) (acc1 >> 31);
- *pOut++ = (q31_t) (acc2 >> 31);
-
- /* Increment the pointer pIn1 index, count by 3 */
- count += 3u;
-
- /* Update the inputA and inputB pointers for next MAC calculation */
- px = pIn1 + count;
- py = pSrc2;
-
- /* Decrement the loop counter */
- blkCnt--;
- }
-
- /* If the blockSize2 is not a multiple of 3, compute any remaining output samples here.
- ** No loop unrolling is used. */
- blkCnt = blockSize2 - 3 * (blockSize2 / 3);
-
- 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);
-
- /* Increment the MAC count */
- count++;
-
- /* Update the inputA and inputB pointers for next MAC calculation */
- px = pIn1 + count;
- py = pSrc2;
-
- /* 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;
-
- /* srcBLen number of MACS should be performed */
- 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);
-
- /* Increment the MAC count */
- count++;
-
- /* Update the inputA and inputB pointers for next MAC calculation */
- px = pIn1 + count;
- py = pSrc2;
-
- /* Decrement the loop counter */
- blkCnt--;
- }
- }
-
-
- /* --------------------------
- * Initializations of stage3
- * -------------------------*/
-
- /* sum += x[srcALen-srcBLen+1] * y[srcBLen-1] + x[srcALen-srcBLen+2] * y[srcBLen-2] +...+ x[srcALen-1] * y[1]
- * sum += x[srcALen-srcBLen+2] * y[srcBLen-1] + x[srcALen-srcBLen+3] * y[srcBLen-2] +...+ x[srcALen-1] * y[2]
- * ....
- * sum += x[srcALen-2] * y[srcBLen-1] + x[srcALen-1] * y[srcBLen-2]
- * sum += x[srcALen-1] * y[srcBLen-1]
- */
-
- /* In this stage the MAC operations are decreased by 1 for every iteration.
- The blockSize3 variable holds the number of MAC operations performed */
-
- /* Working pointer of inputA */
- pSrc1 = (pIn1 + srcALen) - (srcBLen - 1u);
- px = pSrc1;
-
- /* Working pointer of inputB */
- pSrc2 = pIn2 + (srcBLen - 1u);
- py = pSrc2;
-
- /* -------------------
- * Stage3 process
- * ------------------*/
-
- while(blockSize3 > 0u)
- {
- /* Accumulator is made zero for every iteration */
- sum = 0;
-
- /* Apply loop unrolling and compute 4 MACs simultaneously. */
- k = blockSize3 >> 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)
- {
- /* sum += x[srcALen - srcBLen + 1] * y[srcBLen - 1] */
- sum += (q63_t) * px++ * (*py--);
- /* sum += x[srcALen - srcBLen + 2] * y[srcBLen - 2] */
- sum += (q63_t) * px++ * (*py--);
- /* sum += x[srcALen - srcBLen + 3] * y[srcBLen - 3] */
- sum += (q63_t) * px++ * (*py--);
- /* sum += x[srcALen - srcBLen + 4] * y[srcBLen - 4] */
- sum += (q63_t) * px++ * (*py--);
-
- /* Decrement the loop counter */
- k--;
- }
-
- /* If the blockSize3 is not a multiple of 4, compute any remaining MACs here.
- ** No loop unrolling is used. */
- k = blockSize3 % 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);
-
- /* Update the inputA and inputB pointers for next MAC calculation */
- px = ++pSrc1;
- py = pSrc2;
-
- /* Decrement the loop counter */
- blockSize3--;
- }
-
- #else
-
- /* Run the below code for Cortex-M0 */
-
- q31_t *pIn1 = pSrcA; /* input pointer */
- q31_t *pIn2 = pSrcB; /* coefficient pointer */
- q63_t sum; /* Accumulator */
- uint32_t i, j; /* loop counter */
-
- /* Loop to calculate output of convolution for output length number of times */
- for (i = 0; i < (srcALen + srcBLen - 1); i++)
- {
- /* Initialize sum with zero to carry on MAC operations */
- sum = 0;
-
- /* Loop to perform MAC operations according to convolution equation */
- for (j = 0; 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[i - j]));
- }
- }
-
- /* Store the output in the destination buffer */
- pDst[i] = (q31_t) (sum >> 31u);
- }
-
- #endif /* #ifndef ARM_MATH_CM0_FAMILY */
-
- }
-
- /**
- * @} end of Conv group
- */
|