diff options
Diffstat (limited to 'Drivers/CMSIS/DSP/Source/FilteringFunctions/arm_fir_decimate_q15.c')
| -rw-r--r-- | Drivers/CMSIS/DSP/Source/FilteringFunctions/arm_fir_decimate_q15.c | 595 |
1 files changed, 595 insertions, 0 deletions
diff --git a/Drivers/CMSIS/DSP/Source/FilteringFunctions/arm_fir_decimate_q15.c b/Drivers/CMSIS/DSP/Source/FilteringFunctions/arm_fir_decimate_q15.c new file mode 100644 index 0000000..4179194 --- /dev/null +++ b/Drivers/CMSIS/DSP/Source/FilteringFunctions/arm_fir_decimate_q15.c @@ -0,0 +1,595 @@ +/* ----------------------------------------------------------------------
+ * Project: CMSIS DSP Library
+ * Title: arm_fir_decimate_q15.c
+ * Description: Q15 FIR Decimator
+ *
+ * $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 FIR_decimate
+ @{
+ */
+
+/**
+ @brief Processing function for the Q15 FIR decimator.
+ @param[in] S points to an instance of the Q15 FIR decimator structure
+ @param[in] pSrc points to the block of input data
+ @param[out] pDst points to the block of output data
+ @param[in] blockSize number of input samples to process per call
+ @return none
+
+ @par Scaling and Overflow Behavior
+ The function is implemented using a 64-bit internal accumulator.
+ Both coefficients and state variables are represented 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.
+ There is no risk of internal overflow with this approach and the full precision of intermediate multiplications is preserved.
+ After all additions have been performed, the accumulator is truncated to 34.15 format by discarding low 15 bits.
+ Lastly, the accumulator is saturated to yield a result in 1.15 format.
+
+ @remark
+ Refer to \ref arm_fir_decimate_fast_q15() for a faster but less precise implementation of this function.
+ */
+
+#if defined (ARM_MATH_DSP)
+
+void arm_fir_decimate_q15(
+ const arm_fir_decimate_instance_q15 * S,
+ const q15_t * pSrc,
+ q15_t * pDst,
+ uint32_t blockSize)
+{
+ q15_t *pState = S->pState; /* State pointer */
+ const q15_t *pCoeffs = S->pCoeffs; /* Coefficient pointer */
+ q15_t *pStateCur; /* Points to the current sample of the state */
+ q15_t *px; /* Temporary pointer for state buffer */
+ const q15_t *pb; /* Temporary pointer for coefficient buffer */
+ q31_t x0, x1, c0; /* Temporary variables to hold state and coefficient values */
+ q63_t sum0; /* Accumulators */
+ q63_t acc0, acc1;
+ q15_t *px0, *px1;
+ uint32_t blkCntN3;
+ uint32_t numTaps = S->numTaps; /* Number of taps */
+ uint32_t i, blkCnt, tapCnt, outBlockSize = blockSize / S->M; /* Loop counters */
+
+#if defined (ARM_MATH_LOOPUNROLL)
+ q31_t c1; /* Temporary variables to hold state and coefficient values */
+#endif
+
+ /* S->pState buffer contains previous frame (numTaps - 1) samples */
+ /* pStateCur points to the location where the new input data should be written */
+ pStateCur = S->pState + (numTaps - 1U);
+
+ /* Total number of output samples to be computed */
+ blkCnt = outBlockSize / 2;
+ blkCntN3 = outBlockSize - (2 * blkCnt);
+
+ while (blkCnt > 0U)
+ {
+ /* Copy 2 * decimation factor number of new input samples into the state buffer */
+ i = S->M * 2;
+
+ do
+ {
+ *pStateCur++ = *pSrc++;
+
+ } while (--i);
+
+ /* Set accumulator to zero */
+ acc0 = 0;
+ acc1 = 0;
+
+ /* Initialize state pointer for all the samples */
+ px0 = pState;
+ px1 = pState + S->M;
+
+ /* Initialize coeff pointer */
+ pb = pCoeffs;
+
+#if defined (ARM_MATH_LOOPUNROLL)
+
+ /* Loop unrolling: Compute 4 taps at a time */
+ tapCnt = numTaps >> 2U;
+
+ while (tapCnt > 0U)
+ {
+ /* Read the b[numTaps-1] and b[numTaps-2] coefficients */
+ c0 = read_q15x2_ia ((q15_t **) &pb);
+
+ /* Read x[n-numTaps-1] and x[n-numTaps-2]sample */
+ x0 = read_q15x2_ia (&px0);
+ x1 = read_q15x2_ia (&px1);
+
+ /* Perform the multiply-accumulate */
+ acc0 = __SMLALD(x0, c0, acc0);
+ acc1 = __SMLALD(x1, c0, acc1);
+
+ /* Read the b[numTaps-3] and b[numTaps-4] coefficient */
+ c0 = read_q15x2_ia ((q15_t **) &pb);
+
+ /* Read x[n-numTaps-2] and x[n-numTaps-3] sample */
+ x0 = read_q15x2_ia (&px0);
+ x1 = read_q15x2_ia (&px1);
+
+ /* Perform the multiply-accumulate */
+ acc0 = __SMLALD(x0, c0, acc0);
+ acc1 = __SMLALD(x1, c0, acc1);
+
+ /* Decrement loop counter */
+ tapCnt--;
+ }
+
+ /* Loop unrolling: Compute remaining taps */
+ tapCnt = numTaps % 0x4U;
+
+#else
+
+ /* Initialize tapCnt with number of taps */
+ tapCnt = numTaps;
+
+#endif /* #if defined (ARM_MATH_LOOPUNROLL) */
+
+ while (tapCnt > 0U)
+ {
+ /* Read coefficients */
+ c0 = *pb++;
+
+ /* Fetch state variables for acc0, acc1 */
+ x0 = *px0++;
+ x1 = *px1++;
+
+ /* Perform the multiply-accumulate */
+ acc0 = __SMLALD(x0, c0, acc0);
+ acc1 = __SMLALD(x1, c0, acc1);
+
+ /* Decrement loop counter */
+ tapCnt--;
+ }
+
+ /* Advance the state pointer by the decimation factor
+ * to process the next group of decimation factor number samples */
+ pState = pState + S->M * 2;
+
+ /* Store filter output, smlad returns the values in 2.14 format */
+ /* so downsacle by 15 to get output in 1.15 */
+ *pDst++ = (q15_t) (__SSAT((acc0 >> 15), 16));
+ *pDst++ = (q15_t) (__SSAT((acc1 >> 15), 16));
+
+ /* Decrement loop counter */
+ blkCnt--;
+ }
+
+ while (blkCntN3 > 0U)
+ {
+ /* Copy decimation factor number of new input samples into the state buffer */
+ i = S->M;
+
+ do
+ {
+ *pStateCur++ = *pSrc++;
+
+ } while (--i);
+
+ /* Set accumulator to zero */
+ sum0 = 0;
+
+ /* Initialize state pointer */
+ px = pState;
+
+ /* Initialize coeff pointer */
+ pb = pCoeffs;
+
+#if defined (ARM_MATH_LOOPUNROLL)
+
+ /* Loop unrolling: Compute 4 taps at a time */
+ tapCnt = numTaps >> 2U;
+
+ while (tapCnt > 0U)
+ {
+ /* Read the b[numTaps-1] and b[numTaps-2] coefficients */
+ c0 = read_q15x2_ia ((q15_t **) &pb);
+
+ /* Read x[n-numTaps-1] and x[n-numTaps-2] sample */
+ x0 = read_q15x2_ia (&px);
+
+ /* Read the b[numTaps-3] and b[numTaps-4] coefficients */
+ c1 = read_q15x2_ia ((q15_t **) &pb);
+
+ /* Perform the multiply-accumulate */
+ sum0 = __SMLALD(x0, c0, sum0);
+
+ /* Read x[n-numTaps-2] and x[n-numTaps-3] sample */
+ x0 = read_q15x2_ia (&px);
+
+ /* Perform the multiply-accumulate */
+ sum0 = __SMLALD(x0, c1, sum0);
+
+ /* Decrement loop counter */
+ tapCnt--;
+ }
+
+ /* Loop unrolling: Compute remaining taps */
+ tapCnt = numTaps % 0x4U;
+
+#else
+
+ /* Initialize tapCnt with number of taps */
+ tapCnt = numTaps;
+
+#endif /* #if defined (ARM_MATH_LOOPUNROLL) */
+
+ while (tapCnt > 0U)
+ {
+ /* Read coefficients */
+ c0 = *pb++;
+
+ /* Fetch 1 state variable */
+ x0 = *px++;
+
+ /* Perform the multiply-accumulate */
+ sum0 = __SMLALD(x0, c0, sum0);
+
+ /* Decrement loop counter */
+ tapCnt--;
+ }
+
+ /* Advance the state pointer by the decimation factor
+ * to process the next group of decimation factor number samples */
+ pState = pState + S->M;
+
+ /* Store filter output, smlad returns the values in 2.14 format */
+ /* so downsacle by 15 to get output in 1.15 */
+ *pDst++ = (q15_t) (__SSAT((sum0 >> 15), 16));
+
+ /* Decrement loop counter */
+ blkCntN3--;
+ }
+
+ /* Processing is complete.
+ Now copy the last numTaps - 1 samples to the satrt of the state buffer.
+ This prepares the state buffer for the next function call. */
+
+ /* Points to the start of the state buffer */
+ pStateCur = S->pState;
+
+ i = (numTaps - 1U) >> 2U;
+
+ /* copy data */
+ while (i > 0U)
+ {
+ write_q15x2_ia (&pStateCur, read_q15x2_ia (&pState));
+ write_q15x2_ia (&pStateCur, read_q15x2_ia (&pState));
+
+ /* Decrement loop counter */
+ i--;
+ }
+
+ i = (numTaps - 1U) % 0x04U;
+
+ /* Copy data */
+ while (i > 0U)
+ {
+ *pStateCur++ = *pState++;
+
+ /* Decrement loop counter */
+ i--;
+ }
+
+}
+
+#else /* #if defined (ARM_MATH_DSP) */
+
+void arm_fir_decimate_q15(
+ const arm_fir_decimate_instance_q15 * S,
+ const q15_t * pSrc,
+ q15_t * pDst,
+ uint32_t blockSize)
+{
+ q15_t *pState = S->pState; /* State pointer */
+ const q15_t *pCoeffs = S->pCoeffs; /* Coefficient pointer */
+ q15_t *pStateCur; /* Points to the current sample of the state */
+ q15_t *px; /* Temporary pointer for state buffer */
+ const q15_t *pb; /* Temporary pointer for coefficient buffer */
+ q15_t x0, x1, c0; /* Temporary variables to hold state and coefficient values */
+ q63_t sum0; /* Accumulators */
+ q63_t acc0, acc1;
+ q15_t *px0, *px1;
+ uint32_t blkCntN3;
+ uint32_t numTaps = S->numTaps; /* Number of taps */
+ uint32_t i, blkCnt, tapCnt, outBlockSize = blockSize / S->M; /* Loop counters */
+
+
+ /* S->pState buffer contains previous frame (numTaps - 1) samples */
+ /* pStateCur points to the location where the new input data should be written */
+ pStateCur = S->pState + (numTaps - 1U);
+
+ /* Total number of output samples to be computed */
+ blkCnt = outBlockSize / 2;
+ blkCntN3 = outBlockSize - (2 * blkCnt);
+
+ while (blkCnt > 0U)
+ {
+ /* Copy 2 * decimation factor number of new input samples into the state buffer */
+ i = S->M * 2;
+
+ do
+ {
+ *pStateCur++ = *pSrc++;
+
+ } while (--i);
+
+ /* Set accumulator to zero */
+ acc0 = 0;
+ acc1 = 0;
+
+ /* Initialize state pointer */
+ px0 = pState;
+ px1 = pState + S->M;
+
+ /* Initialize coeff pointer */
+ pb = pCoeffs;
+
+#if defined (ARM_MATH_LOOPUNROLL)
+
+ /* Loop unrolling: Compute 4 taps at a time */
+ tapCnt = numTaps >> 2U;
+
+ while (tapCnt > 0U)
+ {
+ /* Read the Read b[numTaps-1] coefficients */
+ c0 = *pb++;
+
+ /* Read x[n-numTaps-1] for sample 0 and for sample 1 */
+ x0 = *px0++;
+ x1 = *px1++;
+
+ /* Perform the multiply-accumulate */
+ acc0 += x0 * c0;
+ acc1 += x1 * c0;
+
+ /* Read the b[numTaps-2] coefficient */
+ c0 = *pb++;
+
+ /* Read x[n-numTaps-2] for sample 0 and sample 1 */
+ x0 = *px0++;
+ x1 = *px1++;
+
+ /* Perform the multiply-accumulate */
+ acc0 += x0 * c0;
+ acc1 += x1 * c0;
+
+ /* Read the b[numTaps-3] coefficients */
+ c0 = *pb++;
+
+ /* Read x[n-numTaps-3] for sample 0 and sample 1 */
+ x0 = *px0++;
+ x1 = *px1++;
+
+ /* Perform the multiply-accumulate */
+ acc0 += x0 * c0;
+ acc1 += x1 * c0;
+
+ /* Read the b[numTaps-4] coefficient */
+ c0 = *pb++;
+
+ /* Read x[n-numTaps-4] for sample 0 and sample 1 */
+ x0 = *px0++;
+ x1 = *px1++;
+
+ /* Perform the multiply-accumulate */
+ acc0 += x0 * c0;
+ acc1 += x1 * c0;
+
+ /* Decrement the loop counter */
+ tapCnt--;
+ }
+
+ /* Loop unrolling: Compute remaining taps */
+ tapCnt = numTaps % 0x4U;
+
+#else
+
+ /* Initialize tapCnt with number of taps */
+ tapCnt = numTaps;
+
+#endif /* #if defined (ARM_MATH_LOOPUNROLL) */
+
+ while (tapCnt > 0U)
+ {
+ /* Read coefficients */
+ c0 = *pb++;
+
+ /* Fetch 1 state variable */
+ x0 = *px0++;
+ x1 = *px1++;
+
+ /* Perform the multiply-accumulate */
+ acc0 += x0 * c0;
+ acc1 += x1 * c0;
+
+ /* Decrement the loop counter */
+ tapCnt--;
+ }
+
+ /* Advance the state pointer by the decimation factor
+ * to process the next group of decimation factor number samples */
+ pState = pState + S->M * 2;
+
+ /* Store filter output, smlad returns the values in 2.14 format */
+ /* so downsacle by 15 to get output in 1.15 */
+
+ *pDst++ = (q15_t) (__SSAT((acc0 >> 15), 16));
+ *pDst++ = (q15_t) (__SSAT((acc1 >> 15), 16));
+
+ /* Decrement loop counter */
+ blkCnt--;
+ }
+
+ while (blkCntN3 > 0U)
+ {
+ /* Copy decimation factor number of new input samples into the state buffer */
+ i = S->M;
+
+ do
+ {
+ *pStateCur++ = *pSrc++;
+
+ } while (--i);
+
+ /* Set accumulator to zero */
+ sum0 = 0;
+
+ /* Initialize state pointer */
+ px = pState;
+
+ /* Initialize coeff pointer */
+ pb = pCoeffs;
+
+#if defined (ARM_MATH_LOOPUNROLL)
+
+ /* Loop unrolling: Compute 4 taps at a time */
+ tapCnt = numTaps >> 2U;
+
+ while (tapCnt > 0U)
+ {
+ /* Read the b[numTaps-1] coefficient */
+ c0 = *pb++;
+
+ /* Read x[n-numTaps-1] sample */
+ x0 = *px++;
+
+ /* Perform the multiply-accumulate */
+ sum0 += x0 * c0;
+
+ /* Read the b[numTaps-2] coefficient */
+ c0 = *pb++;
+
+ /* Read x[n-numTaps-2] sample */
+ x0 = *px++;
+
+ /* Perform the multiply-accumulate */
+ sum0 += x0 * c0;
+
+ /* Read the b[numTaps-3] coefficient */
+ c0 = *pb++;
+
+ /* Read x[n-numTaps-3] sample */
+ x0 = *px++;
+
+ /* Perform the multiply-accumulate */
+ sum0 += x0 * c0;
+
+ /* Read the b[numTaps-4] coefficient */
+ c0 = *pb++;
+
+ /* Read x[n-numTaps-4] sample */
+ x0 = *px++;
+
+ /* Perform the multiply-accumulate */
+ sum0 += x0 * c0;
+
+ /* Decrement loop counter */
+ tapCnt--;
+ }
+
+ /* Loop unrolling: Compute remaining taps */
+ tapCnt = numTaps % 0x4U;
+
+#else
+
+ /* Initialize tapCnt with number of taps */
+ tapCnt = numTaps;
+
+#endif /* #if defined (ARM_MATH_LOOPUNROLL) */
+
+ while (tapCnt > 0U)
+ {
+ /* Read coefficients */
+ c0 = *pb++;
+
+ /* Fetch 1 state variable */
+ x0 = *px++;
+
+ /* Perform the multiply-accumulate */
+ sum0 += x0 * c0;
+
+ /* Decrement the loop counter */
+ tapCnt--;
+ }
+
+ /* Advance the state pointer by the decimation factor
+ * to process the next group of decimation factor number samples */
+ pState = pState + S->M;
+
+ /* Store filter output, smlad returns the values in 2.14 format */
+ /* so downsacle by 15 to get output in 1.15 */
+ *pDst++ = (q15_t) (__SSAT((sum0 >> 15), 16));
+
+ /* Decrement loop counter */
+ blkCntN3--;
+ }
+
+ /* Processing is complete.
+ ** Now copy the last numTaps - 1 samples to the satrt of the state buffer.
+ ** This prepares the state buffer for the next function call. */
+
+ /* Points to the start of the state buffer */
+ pStateCur = S->pState;
+
+ i = (numTaps - 1U) >> 2U;
+
+ /* copy data */
+ while (i > 0U)
+ {
+ *pStateCur++ = *pState++;
+ *pStateCur++ = *pState++;
+ *pStateCur++ = *pState++;
+ *pStateCur++ = *pState++;
+
+ /* Decrement loop counter */
+ i--;
+ }
+
+ i = (numTaps - 1U) % 0x04U;
+
+ /* copy data */
+ while (i > 0U)
+ {
+ *pStateCur++ = *pState++;
+
+ /* Decrement loop counter */
+ i--;
+ }
+}
+
+#endif /* #if defined (ARM_MATH_DSP) */
+
+/**
+ @} end of FIR_decimate group
+ */
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