| /* ---------------------------------------------------------------------- |
| * 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_opt_q15.c |
| * |
| * Description: Correlation of Q15 sequences. |
| * |
| * 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. |
| * @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. |
| * @param[in] *pScratch points to scratch buffer of size max(srcALen, srcBLen) + 2*min(srcALen, srcBLen) - 2. |
| * @return none. |
| * |
| * \par Restrictions |
| * If the silicon does not support unaligned memory access enable the macro UNALIGNED_SUPPORT_DISABLE |
| * In this case input, output, scratch buffers should be aligned by 32-bit |
| * |
| * @details |
| * <b>Scaling and Overflow Behavior:</b> |
| * |
| * \par |
| * The function is implemented using a 64-bit internal accumulator. |
| * Both inputs are in 1.15 format and multiplications yield a 2.30 result. |
| * The 2.30 intermediate results are accumulated in a 64-bit accumulator in 34.30 format. |
| * This approach provides 33 guard bits and there is no risk of overflow. |
| * The 34.30 result is then truncated to 34.15 format by discarding the low 15 bits and then saturated to 1.15 format. |
| * |
| * \par |
| * Refer to <code>arm_correlate_fast_q15()</code> for a faster but less precise version of this function for Cortex-M3 and Cortex-M4. |
| * |
| * |
| */ |
| |
| |
| void arm_correlate_opt_q15( |
| q15_t * pSrcA, |
| uint32_t srcALen, |
| q15_t * pSrcB, |
| uint32_t srcBLen, |
| q15_t * pDst, |
| q15_t * pScratch) |
| { |
| q15_t *pIn1; /* inputA pointer */ |
| q15_t *pIn2; /* inputB pointer */ |
| q63_t acc0, acc1, acc2, acc3; /* Accumulators */ |
| q15_t *py; /* Intermediate inputB pointer */ |
| q31_t x1, x2, x3; /* temporary variables for holding input1 and input2 values */ |
| uint32_t j, blkCnt, outBlockSize; /* loop counter */ |
| int32_t inc = 1; /* output pointer increment */ |
| uint32_t tapCnt; |
| q31_t y1, y2; |
| q15_t *pScr; /* Intermediate pointers */ |
| q15_t *pOut = pDst; /* output pointer */ |
| #ifdef UNALIGNED_SUPPORT_DISABLE |
| |
| q15_t a, b; |
| |
| #endif /* #ifndef UNALIGNED_SUPPORT_DISABLE */ |
| |
| /* 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; |
| |
| } |
| |
| pScr = pScratch; |
| |
| /* Fill (srcBLen - 1u) zeros in scratch buffer */ |
| arm_fill_q15(0, pScr, (srcBLen - 1u)); |
| |
| /* Update temporary scratch pointer */ |
| pScr += (srcBLen - 1u); |
| |
| #ifndef UNALIGNED_SUPPORT_DISABLE |
| |
| /* Copy (srcALen) samples in scratch buffer */ |
| arm_copy_q15(pIn1, pScr, srcALen); |
| |
| /* Update pointers */ |
| //pIn1 += srcALen; |
| pScr += srcALen; |
| |
| #else |
| |
| /* Apply loop unrolling and do 4 Copies simultaneously. */ |
| j = srcALen >> 2u; |
| |
| /* First part of the processing with loop unrolling copies 4 data points at a time. |
| ** a second loop below copies for the remaining 1 to 3 samples. */ |
| while(j > 0u) |
| { |
| /* copy second buffer in reversal manner */ |
| *pScr++ = *pIn1++; |
| *pScr++ = *pIn1++; |
| *pScr++ = *pIn1++; |
| *pScr++ = *pIn1++; |
| |
| /* Decrement the loop counter */ |
| j--; |
| } |
| |
| /* If the count is not a multiple of 4, copy remaining samples here. |
| ** No loop unrolling is used. */ |
| j = srcALen % 0x4u; |
| |
| while(j > 0u) |
| { |
| /* copy second buffer in reversal manner for remaining samples */ |
| *pScr++ = *pIn1++; |
| |
| /* Decrement the loop counter */ |
| j--; |
| } |
| |
| #endif /* #ifndef UNALIGNED_SUPPORT_DISABLE */ |
| |
| #ifndef UNALIGNED_SUPPORT_DISABLE |
| |
| /* Fill (srcBLen - 1u) zeros at end of scratch buffer */ |
| arm_fill_q15(0, pScr, (srcBLen - 1u)); |
| |
| /* Update pointer */ |
| pScr += (srcBLen - 1u); |
| |
| #else |
| |
| /* Apply loop unrolling and do 4 Copies simultaneously. */ |
| j = (srcBLen - 1u) >> 2u; |
| |
| /* First part of the processing with loop unrolling copies 4 data points at a time. |
| ** a second loop below copies for the remaining 1 to 3 samples. */ |
| while(j > 0u) |
| { |
| /* copy second buffer in reversal manner */ |
| *pScr++ = 0; |
| *pScr++ = 0; |
| *pScr++ = 0; |
| *pScr++ = 0; |
| |
| /* Decrement the loop counter */ |
| j--; |
| } |
| |
| /* If the count is not a multiple of 4, copy remaining samples here. |
| ** No loop unrolling is used. */ |
| j = (srcBLen - 1u) % 0x4u; |
| |
| while(j > 0u) |
| { |
| /* copy second buffer in reversal manner for remaining samples */ |
| *pScr++ = 0; |
| |
| /* Decrement the loop counter */ |
| j--; |
| } |
| |
| #endif /* #ifndef UNALIGNED_SUPPORT_DISABLE */ |
| |
| /* Temporary pointer for scratch2 */ |
| py = pIn2; |
| |
| |
| /* Actual correlation process starts here */ |
| blkCnt = (srcALen + srcBLen - 1u) >> 2; |
| |
| while(blkCnt > 0) |
| { |
| /* Initialze temporary scratch pointer as scratch1 */ |
| pScr = pScratch; |
| |
| /* Clear Accumlators */ |
| acc0 = 0; |
| acc1 = 0; |
| acc2 = 0; |
| acc3 = 0; |
| |
| /* Read four samples from scratch1 buffer */ |
| x1 = *__SIMD32(pScr)++; |
| |
| /* Read next four samples from scratch1 buffer */ |
| x2 = *__SIMD32(pScr)++; |
| |
| tapCnt = (srcBLen) >> 2u; |
| |
| while(tapCnt > 0u) |
| { |
| |
| #ifndef UNALIGNED_SUPPORT_DISABLE |
| |
| /* Read four samples from smaller buffer */ |
| y1 = _SIMD32_OFFSET(pIn2); |
| y2 = _SIMD32_OFFSET(pIn2 + 2u); |
| |
| acc0 = __SMLALD(x1, y1, acc0); |
| |
| acc2 = __SMLALD(x2, y1, acc2); |
| |
| #ifndef ARM_MATH_BIG_ENDIAN |
| x3 = __PKHBT(x2, x1, 0); |
| #else |
| x3 = __PKHBT(x1, x2, 0); |
| #endif |
| |
| acc1 = __SMLALDX(x3, y1, acc1); |
| |
| x1 = _SIMD32_OFFSET(pScr); |
| |
| acc0 = __SMLALD(x2, y2, acc0); |
| |
| acc2 = __SMLALD(x1, y2, acc2); |
| |
| #ifndef ARM_MATH_BIG_ENDIAN |
| x3 = __PKHBT(x1, x2, 0); |
| #else |
| x3 = __PKHBT(x2, x1, 0); |
| #endif |
| |
| acc3 = __SMLALDX(x3, y1, acc3); |
| |
| acc1 = __SMLALDX(x3, y2, acc1); |
| |
| x2 = _SIMD32_OFFSET(pScr + 2u); |
| |
| #ifndef ARM_MATH_BIG_ENDIAN |
| x3 = __PKHBT(x2, x1, 0); |
| #else |
| x3 = __PKHBT(x1, x2, 0); |
| #endif |
| |
| acc3 = __SMLALDX(x3, y2, acc3); |
| |
| #else |
| |
| /* Read four samples from smaller buffer */ |
| a = *pIn2; |
| b = *(pIn2 + 1); |
| |
| #ifndef ARM_MATH_BIG_ENDIAN |
| y1 = __PKHBT(a, b, 16); |
| #else |
| y1 = __PKHBT(b, a, 16); |
| #endif |
| |
| a = *(pIn2 + 2); |
| b = *(pIn2 + 3); |
| #ifndef ARM_MATH_BIG_ENDIAN |
| y2 = __PKHBT(a, b, 16); |
| #else |
| y2 = __PKHBT(b, a, 16); |
| #endif |
| |
| acc0 = __SMLALD(x1, y1, acc0); |
| |
| acc2 = __SMLALD(x2, y1, acc2); |
| |
| #ifndef ARM_MATH_BIG_ENDIAN |
| x3 = __PKHBT(x2, x1, 0); |
| #else |
| x3 = __PKHBT(x1, x2, 0); |
| #endif |
| |
| acc1 = __SMLALDX(x3, y1, acc1); |
| |
| a = *pScr; |
| b = *(pScr + 1); |
| |
| #ifndef ARM_MATH_BIG_ENDIAN |
| x1 = __PKHBT(a, b, 16); |
| #else |
| x1 = __PKHBT(b, a, 16); |
| #endif |
| |
| acc0 = __SMLALD(x2, y2, acc0); |
| |
| acc2 = __SMLALD(x1, y2, acc2); |
| |
| #ifndef ARM_MATH_BIG_ENDIAN |
| x3 = __PKHBT(x1, x2, 0); |
| #else |
| x3 = __PKHBT(x2, x1, 0); |
| #endif |
| |
| acc3 = __SMLALDX(x3, y1, acc3); |
| |
| acc1 = __SMLALDX(x3, y2, acc1); |
| |
| a = *(pScr + 2); |
| b = *(pScr + 3); |
| |
| #ifndef ARM_MATH_BIG_ENDIAN |
| x2 = __PKHBT(a, b, 16); |
| #else |
| x2 = __PKHBT(b, a, 16); |
| #endif |
| |
| #ifndef ARM_MATH_BIG_ENDIAN |
| x3 = __PKHBT(x2, x1, 0); |
| #else |
| x3 = __PKHBT(x1, x2, 0); |
| #endif |
| |
| acc3 = __SMLALDX(x3, y2, acc3); |
| |
| #endif /* #ifndef UNALIGNED_SUPPORT_DISABLE */ |
| |
| pIn2 += 4u; |
| |
| pScr += 4u; |
| |
| |
| /* Decrement the loop counter */ |
| tapCnt--; |
| } |
| |
| |
| |
| /* Update scratch pointer for remaining samples of smaller length sequence */ |
| pScr -= 4u; |
| |
| |
| /* apply same above for remaining samples of smaller length sequence */ |
| tapCnt = (srcBLen) & 3u; |
| |
| while(tapCnt > 0u) |
| { |
| |
| /* accumlate the results */ |
| acc0 += (*pScr++ * *pIn2); |
| acc1 += (*pScr++ * *pIn2); |
| acc2 += (*pScr++ * *pIn2); |
| acc3 += (*pScr++ * *pIn2++); |
| |
| pScr -= 3u; |
| |
| /* Decrement the loop counter */ |
| tapCnt--; |
| } |
| |
| blkCnt--; |
| |
| |
| /* Store the results in the accumulators in the destination buffer. */ |
| *pOut = (__SSAT(acc0 >> 15u, 16)); |
| pOut += inc; |
| *pOut = (__SSAT(acc1 >> 15u, 16)); |
| pOut += inc; |
| *pOut = (__SSAT(acc2 >> 15u, 16)); |
| pOut += inc; |
| *pOut = (__SSAT(acc3 >> 15u, 16)); |
| pOut += inc; |
| |
| /* Initialization of inputB pointer */ |
| pIn2 = py; |
| |
| pScratch += 4u; |
| |
| } |
| |
| |
| blkCnt = (srcALen + srcBLen - 1u) & 0x3; |
| |
| /* Calculate correlation for remaining samples of Bigger length sequence */ |
| while(blkCnt > 0) |
| { |
| /* Initialze temporary scratch pointer as scratch1 */ |
| pScr = pScratch; |
| |
| /* Clear Accumlators */ |
| acc0 = 0; |
| |
| tapCnt = (srcBLen) >> 1u; |
| |
| while(tapCnt > 0u) |
| { |
| |
| acc0 += (*pScr++ * *pIn2++); |
| acc0 += (*pScr++ * *pIn2++); |
| |
| /* Decrement the loop counter */ |
| tapCnt--; |
| } |
| |
| tapCnt = (srcBLen) & 1u; |
| |
| /* apply same above for remaining samples of smaller length sequence */ |
| while(tapCnt > 0u) |
| { |
| |
| /* accumlate the results */ |
| acc0 += (*pScr++ * *pIn2++); |
| |
| /* Decrement the loop counter */ |
| tapCnt--; |
| } |
| |
| blkCnt--; |
| |
| /* Store the result in the accumulator in the destination buffer. */ |
| *pOut = (q15_t) (__SSAT((acc0 >> 15), 16)); |
| |
| pOut += inc; |
| |
| /* Initialization of inputB pointer */ |
| pIn2 = py; |
| |
| pScratch += 1u; |
| |
| } |
| |
| |
| } |
| |
| /** |
| * @} end of Corr group |
| */ |