diff options
Diffstat (limited to 'Drivers/CMSIS/DSP/Source/FilteringFunctions/arm_correlate_opt_q15.c')
| -rw-r--r-- | Drivers/CMSIS/DSP/Source/FilteringFunctions/arm_correlate_opt_q15.c | 341 |
1 files changed, 341 insertions, 0 deletions
diff --git a/Drivers/CMSIS/DSP/Source/FilteringFunctions/arm_correlate_opt_q15.c b/Drivers/CMSIS/DSP/Source/FilteringFunctions/arm_correlate_opt_q15.c new file mode 100644 index 0000000..ae0ab45 --- /dev/null +++ b/Drivers/CMSIS/DSP/Source/FilteringFunctions/arm_correlate_opt_q15.c @@ -0,0 +1,341 @@ +/* ----------------------------------------------------------------------
+ * Project: CMSIS DSP Library
+ * Title: arm_correlate_opt_q15.c
+ * Description: Correlation of Q15 sequences
+ *
+ * $Date: 18. March 2019
+ * $Revision: V1.6.0
+ *
+ * Target Processor: Cortex-M cores
+ * -------------------------------------------------------------------- */
+/*
+ * Copyright (C) 2010-2019 ARM Limited or its affiliates. All rights reserved.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Licensed under the Apache License, Version 2.0 (the License); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an AS IS BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#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 Scaling and Overflow Behavior
+ 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.
+
+ @remark
+ Refer to \ref arm_correlate_fast_q15() for a faster but less precise version of this function.
+ */
+
+void arm_correlate_opt_q15(
+ const q15_t * pSrcA,
+ uint32_t srcALen,
+ const q15_t * pSrcB,
+ uint32_t srcBLen,
+ q15_t * pDst,
+ q15_t * pScratch)
+{
+ q63_t acc0; /* Accumulators */
+ q15_t *pOut = pDst; /* Output pointer */
+ q15_t *pScr1; /* Temporary pointer for scratch1 */
+ const q15_t *pIn1; /* InputA pointer */
+ const q15_t *pIn2; /* InputB pointer */
+ const q15_t *py; /* Intermediate inputB pointer */
+ uint32_t j, blkCnt, outBlockSize; /* Loop counter */
+ int32_t inc = 1; /* Output pointer increment */
+ uint32_t tapCnt;
+
+#if defined (ARM_MATH_LOOPUNROLL)
+ q63_t acc1, acc2, acc3; /* Accumulators */
+ q31_t x1, x2, x3; /* Temporary variables for holding input1 and input2 values */
+ q31_t y1, y2; /* State variables */
+#endif
+
+ /* 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 = (srcALen * 2U) - 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;
+ }
+
+ pScr1 = pScratch;
+
+ /* Fill (srcBLen - 1U) zeros in scratch buffer */
+ arm_fill_q15(0, pScr1, (srcBLen - 1U));
+
+ /* Update temporary scratch pointer */
+ pScr1 += (srcBLen - 1U);
+
+ /* Copy (srcALen) samples in scratch buffer */
+ arm_copy_q15(pIn1, pScr1, srcALen);
+
+ /* Update pointers */
+ pScr1 += srcALen;
+
+
+ /* Fill (srcBLen - 1U) zeros at end of scratch buffer */
+ arm_fill_q15(0, pScr1, (srcBLen - 1U));
+
+ /* Update pointer */
+ pScr1 += (srcBLen - 1U);
+
+ /* Temporary pointer for scratch2 */
+ py = pIn2;
+
+
+ /* Actual correlation process starts here */
+#if defined (ARM_MATH_LOOPUNROLL)
+
+ /* Loop unrolling: Compute 4 outputs at a time */
+ blkCnt = (srcALen + srcBLen - 1U) >> 2;
+
+ while (blkCnt > 0)
+ {
+ /* Initialze temporary scratch pointer as scratch1 */
+ pScr1 = pScratch;
+
+ /* Clear Accumlators */
+ acc0 = 0;
+ acc1 = 0;
+ acc2 = 0;
+ acc3 = 0;
+
+ /* Read two samples from scratch1 buffer */
+ x1 = read_q15x2_ia (&pScr1);
+
+ /* Read next two samples from scratch1 buffer */
+ x2 = read_q15x2_ia (&pScr1);
+
+ tapCnt = (srcBLen) >> 2U;
+
+ while (tapCnt > 0U)
+ {
+ /* Read four samples from smaller buffer */
+ y1 = read_q15x2_ia ((q15_t **) &pIn2);
+ y2 = read_q15x2_ia ((q15_t **) &pIn2);
+
+ /* multiply and accumlate */
+ acc0 = __SMLALD(x1, y1, acc0);
+ acc2 = __SMLALD(x2, y1, acc2);
+
+ /* pack input data */
+#ifndef ARM_MATH_BIG_ENDIAN
+ x3 = __PKHBT(x2, x1, 0);
+#else
+ x3 = __PKHBT(x1, x2, 0);
+#endif
+
+ /* multiply and accumlate */
+ acc1 = __SMLALDX(x3, y1, acc1);
+
+ /* Read next two samples from scratch1 buffer */
+ x1 = read_q15x2_ia (&pScr1);
+
+ /* multiply and accumlate */
+ acc0 = __SMLALD(x2, y2, acc0);
+ acc2 = __SMLALD(x1, y2, acc2);
+
+ /* pack input data */
+#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 = read_q15x2_ia (&pScr1);
+
+#ifndef ARM_MATH_BIG_ENDIAN
+ x3 = __PKHBT(x2, x1, 0);
+#else
+ x3 = __PKHBT(x1, x2, 0);
+#endif
+
+ acc3 = __SMLALDX(x3, y2, acc3);
+
+ /* Decrement loop counter */
+ tapCnt--;
+ }
+
+ /* Update scratch pointer for remaining samples of smaller length sequence */
+ pScr1 -= 4U;
+
+ /* apply same above for remaining samples of smaller length sequence */
+ tapCnt = (srcBLen) & 3U;
+
+ while (tapCnt > 0U)
+ {
+ /* accumlate the results */
+ acc0 += (*pScr1++ * *pIn2);
+ acc1 += (*pScr1++ * *pIn2);
+ acc2 += (*pScr1++ * *pIn2);
+ acc3 += (*pScr1++ * *pIn2++);
+
+ pScr1 -= 3U;
+
+ /* Decrement 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;
+ }
+
+
+ /* Loop unrolling: Compute remaining outputs */
+ blkCnt = (srcALen + srcBLen - 1U) & 0x3;
+
+#else
+
+ /* Initialize blkCnt with number of samples */
+ blkCnt = (srcALen + srcBLen - 1U);
+
+#endif /* #if defined (ARM_MATH_LOOPUNROLL) */
+
+ /* Calculate correlation for remaining samples of Bigger length sequence */
+ while (blkCnt > 0)
+ {
+ /* Initialze temporary scratch pointer as scratch1 */
+ pScr1 = pScratch;
+
+ /* Clear Accumlators */
+ acc0 = 0;
+
+ tapCnt = (srcBLen) >> 1U;
+
+ while (tapCnt > 0U)
+ {
+
+ /* Read next two samples from scratch1 buffer */
+ acc0 += (*pScr1++ * *pIn2++);
+ acc0 += (*pScr1++ * *pIn2++);
+
+ /* Decrement loop counter */
+ tapCnt--;
+ }
+
+ tapCnt = (srcBLen) & 1U;
+
+ /* apply same above for remaining samples of smaller length sequence */
+ while (tapCnt > 0U)
+ {
+ /* accumlate the results */
+ acc0 += (*pScr1++ * *pIn2++);
+
+ /* Decrement loop counter */
+ tapCnt--;
+ }
+
+ blkCnt--;
+
+ /* The result is in 2.30 format. Convert to 1.15 with saturation.
+ Then store the output 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
+ */
|