| /* ---------------------------------------------------------------------- |
| * Copyright (C) 2010-2014 ARM Limited. All rights reserved. |
| * |
| * $Date: 19. March 2015 |
| * $Revision: V.1.4.5 |
| * |
| * 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 |
| */ |
