diff options
Diffstat (limited to 'fw/cdc-dials/Drivers/CMSIS/DSP/Source/FilteringFunctions/arm_fir_fast_q15.c')
| -rw-r--r-- | fw/cdc-dials/Drivers/CMSIS/DSP/Source/FilteringFunctions/arm_fir_fast_q15.c | 333 |
1 files changed, 333 insertions, 0 deletions
diff --git a/fw/cdc-dials/Drivers/CMSIS/DSP/Source/FilteringFunctions/arm_fir_fast_q15.c b/fw/cdc-dials/Drivers/CMSIS/DSP/Source/FilteringFunctions/arm_fir_fast_q15.c new file mode 100644 index 0000000..35e431b --- /dev/null +++ b/fw/cdc-dials/Drivers/CMSIS/DSP/Source/FilteringFunctions/arm_fir_fast_q15.c @@ -0,0 +1,333 @@ +/* ----------------------------------------------------------------------
+ * Project: CMSIS DSP Library
+ * Title: arm_fir_fast_q15.c
+ * Description: Q15 Fast FIR filter processing function
+ *
+ * $Date: 27. January 2017
+ * $Revision: V.1.5.1
+ *
+ * Target Processor: Cortex-M cores
+ * -------------------------------------------------------------------- */
+/*
+ * Copyright (C) 2010-2017 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
+ * @{
+ */
+
+/**
+ * @param[in] *S points to an instance of the Q15 FIR filter 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 samples to process per call.
+ * @return none.
+ *
+ * <b>Scaling and Overflow Behavior:</b>
+ * \par
+ * This fast version uses a 32-bit accumulator with 2.30 format.
+ * The accumulator maintains full precision of the intermediate multiplication results but provides only a single guard bit.
+ * Thus, if the accumulator result overflows it wraps around and distorts the result.
+ * In order to avoid overflows completely the input signal must be scaled down by log2(numTaps) bits.
+ * The 2.30 accumulator is then truncated to 2.15 format and saturated to yield the 1.15 result.
+ *
+ * \par
+ * Refer to the function <code>arm_fir_q15()</code> for a slower implementation of this function which uses 64-bit accumulation to avoid wrap around distortion. Both the slow and the fast versions use the same instance structure.
+ * Use the function <code>arm_fir_init_q15()</code> to initialize the filter structure.
+ */
+
+void arm_fir_fast_q15(
+ const arm_fir_instance_q15 * S,
+ q15_t * pSrc,
+ q15_t * pDst,
+ uint32_t blockSize)
+{
+ q15_t *pState = S->pState; /* State pointer */
+ q15_t *pCoeffs = S->pCoeffs; /* Coefficient pointer */
+ q15_t *pStateCurnt; /* Points to the current sample of the state */
+ q31_t acc0, acc1, acc2, acc3; /* Accumulators */
+ q15_t *pb; /* Temporary pointer for coefficient buffer */
+ q15_t *px; /* Temporary q31 pointer for SIMD state buffer accesses */
+ q31_t x0, x1, x2, c0; /* Temporary variables to hold SIMD state and coefficient values */
+ uint32_t numTaps = S->numTaps; /* Number of taps in the filter */
+ uint32_t tapCnt, blkCnt; /* Loop counters */
+
+
+ /* S->pState points to state array which contains previous frame (numTaps - 1) samples */
+ /* pStateCurnt points to the location where the new input data should be written */
+ pStateCurnt = &(S->pState[(numTaps - 1U)]);
+
+ /* Apply loop unrolling and compute 4 output values simultaneously.
+ * The variables acc0 ... acc3 hold output values that are being computed:
+ *
+ * acc0 = b[numTaps-1] * x[n-numTaps-1] + b[numTaps-2] * x[n-numTaps-2] + b[numTaps-3] * x[n-numTaps-3] +...+ b[0] * x[0]
+ * acc1 = b[numTaps-1] * x[n-numTaps] + b[numTaps-2] * x[n-numTaps-1] + b[numTaps-3] * x[n-numTaps-2] +...+ b[0] * x[1]
+ * acc2 = b[numTaps-1] * x[n-numTaps+1] + b[numTaps-2] * x[n-numTaps] + b[numTaps-3] * x[n-numTaps-1] +...+ b[0] * x[2]
+ * acc3 = b[numTaps-1] * x[n-numTaps+2] + b[numTaps-2] * x[n-numTaps+1] + b[numTaps-3] * x[n-numTaps] +...+ b[0] * x[3]
+ */
+
+ blkCnt = blockSize >> 2;
+
+ /* First part of the processing with loop unrolling. Compute 4 outputs at a time.
+ ** a second loop below computes the remaining 1 to 3 samples. */
+ while (blkCnt > 0U)
+ {
+ /* Copy four new input samples into the state buffer.
+ ** Use 32-bit SIMD to move the 16-bit data. Only requires two copies. */
+ *pStateCurnt++ = *pSrc++;
+ *pStateCurnt++ = *pSrc++;
+ *pStateCurnt++ = *pSrc++;
+ *pStateCurnt++ = *pSrc++;
+
+
+ /* Set all accumulators to zero */
+ acc0 = 0;
+ acc1 = 0;
+ acc2 = 0;
+ acc3 = 0;
+
+ /* Typecast q15_t pointer to q31_t pointer for state reading in q31_t */
+ px = pState;
+
+ /* Typecast q15_t pointer to q31_t pointer for coefficient reading in q31_t */
+ pb = pCoeffs;
+
+ /* Read the first two samples from the state buffer: x[n-N], x[n-N-1] */
+ x0 = *__SIMD32(px)++;
+
+ /* Read the third and forth samples from the state buffer: x[n-N-2], x[n-N-3] */
+ x2 = *__SIMD32(px)++;
+
+ /* Loop over the number of taps. Unroll by a factor of 4.
+ ** Repeat until we've computed numTaps-(numTaps%4) coefficients. */
+ tapCnt = numTaps >> 2;
+
+ while (tapCnt > 0)
+ {
+ /* Read the first two coefficients using SIMD: b[N] and b[N-1] coefficients */
+ c0 = *__SIMD32(pb)++;
+
+ /* acc0 += b[N] * x[n-N] + b[N-1] * x[n-N-1] */
+ acc0 = __SMLAD(x0, c0, acc0);
+
+ /* acc2 += b[N] * x[n-N-2] + b[N-1] * x[n-N-3] */
+ acc2 = __SMLAD(x2, c0, acc2);
+
+ /* pack x[n-N-1] and x[n-N-2] */
+#ifndef ARM_MATH_BIG_ENDIAN
+ x1 = __PKHBT(x2, x0, 0);
+#else
+ x1 = __PKHBT(x0, x2, 0);
+#endif
+
+ /* Read state x[n-N-4], x[n-N-5] */
+ x0 = _SIMD32_OFFSET(px);
+
+ /* acc1 += b[N] * x[n-N-1] + b[N-1] * x[n-N-2] */
+ acc1 = __SMLADX(x1, c0, acc1);
+
+ /* pack x[n-N-3] and x[n-N-4] */
+#ifndef ARM_MATH_BIG_ENDIAN
+ x1 = __PKHBT(x0, x2, 0);
+#else
+ x1 = __PKHBT(x2, x0, 0);
+#endif
+
+ /* acc3 += b[N] * x[n-N-3] + b[N-1] * x[n-N-4] */
+ acc3 = __SMLADX(x1, c0, acc3);
+
+ /* Read coefficients b[N-2], b[N-3] */
+ c0 = *__SIMD32(pb)++;
+
+ /* acc0 += b[N-2] * x[n-N-2] + b[N-3] * x[n-N-3] */
+ acc0 = __SMLAD(x2, c0, acc0);
+
+ /* Read state x[n-N-6], x[n-N-7] with offset */
+ x2 = _SIMD32_OFFSET(px + 2U);
+
+ /* acc2 += b[N-2] * x[n-N-4] + b[N-3] * x[n-N-5] */
+ acc2 = __SMLAD(x0, c0, acc2);
+
+ /* acc1 += b[N-2] * x[n-N-3] + b[N-3] * x[n-N-4] */
+ acc1 = __SMLADX(x1, c0, acc1);
+
+ /* pack x[n-N-5] and x[n-N-6] */
+#ifndef ARM_MATH_BIG_ENDIAN
+ x1 = __PKHBT(x2, x0, 0);
+#else
+ x1 = __PKHBT(x0, x2, 0);
+#endif
+
+ /* acc3 += b[N-2] * x[n-N-5] + b[N-3] * x[n-N-6] */
+ acc3 = __SMLADX(x1, c0, acc3);
+
+ /* Update state pointer for next state reading */
+ px += 4U;
+
+ /* Decrement tap count */
+ tapCnt--;
+
+ }
+
+ /* If the filter length is not a multiple of 4, compute the remaining filter taps.
+ ** This is always be 2 taps since the filter length is even. */
+ if ((numTaps & 0x3U) != 0U)
+ {
+
+ /* Read last two coefficients */
+ c0 = *__SIMD32(pb)++;
+
+ /* Perform the multiply-accumulates */
+ acc0 = __SMLAD(x0, c0, acc0);
+ acc2 = __SMLAD(x2, c0, acc2);
+
+ /* pack state variables */
+#ifndef ARM_MATH_BIG_ENDIAN
+ x1 = __PKHBT(x2, x0, 0);
+#else
+ x1 = __PKHBT(x0, x2, 0);
+#endif
+
+ /* Read last state variables */
+ x0 = *__SIMD32(px);
+
+ /* Perform the multiply-accumulates */
+ acc1 = __SMLADX(x1, c0, acc1);
+
+ /* pack state variables */
+#ifndef ARM_MATH_BIG_ENDIAN
+ x1 = __PKHBT(x0, x2, 0);
+#else
+ x1 = __PKHBT(x2, x0, 0);
+#endif
+
+ /* Perform the multiply-accumulates */
+ acc3 = __SMLADX(x1, c0, acc3);
+ }
+
+ /* The results in the 4 accumulators are in 2.30 format. Convert to 1.15 with saturation.
+ ** Then store the 4 outputs in the destination buffer. */
+
+#ifndef ARM_MATH_BIG_ENDIAN
+
+ *__SIMD32(pDst)++ =
+ __PKHBT(__SSAT((acc0 >> 15), 16), __SSAT((acc1 >> 15), 16), 16);
+
+ *__SIMD32(pDst)++ =
+ __PKHBT(__SSAT((acc2 >> 15), 16), __SSAT((acc3 >> 15), 16), 16);
+
+#else
+
+ *__SIMD32(pDst)++ =
+ __PKHBT(__SSAT((acc1 >> 15), 16), __SSAT((acc0 >> 15), 16), 16);
+
+ *__SIMD32(pDst)++ =
+ __PKHBT(__SSAT((acc3 >> 15), 16), __SSAT((acc2 >> 15), 16), 16);
+
+
+#endif /* #ifndef ARM_MATH_BIG_ENDIAN */
+
+ /* Advance the state pointer by 4 to process the next group of 4 samples */
+ pState = pState + 4U;
+
+ /* Decrement the loop counter */
+ blkCnt--;
+ }
+
+ /* If the blockSize is not a multiple of 4, compute any remaining output samples here.
+ ** No loop unrolling is used. */
+ blkCnt = blockSize % 0x4U;
+ while (blkCnt > 0U)
+ {
+ /* Copy two samples into state buffer */
+ *pStateCurnt++ = *pSrc++;
+
+ /* Set the accumulator to zero */
+ acc0 = 0;
+
+ /* Use SIMD to hold states and coefficients */
+ px = pState;
+ pb = pCoeffs;
+
+ tapCnt = numTaps >> 1U;
+
+ do
+ {
+
+ acc0 += (q31_t) * px++ * *pb++;
+ acc0 += (q31_t) * px++ * *pb++;
+
+ tapCnt--;
+ }
+ while (tapCnt > 0U);
+
+ /* The result is in 2.30 format. Convert to 1.15 with saturation.
+ ** Then store the output in the destination buffer. */
+ *pDst++ = (q15_t) (__SSAT((acc0 >> 15), 16));
+
+ /* Advance state pointer by 1 for the next sample */
+ pState = pState + 1U;
+
+ /* Decrement the loop counter */
+ blkCnt--;
+ }
+
+ /* 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 */
+ pStateCurnt = S->pState;
+
+ /* Calculation of count for copying integer writes */
+ tapCnt = (numTaps - 1U) >> 2;
+
+ while (tapCnt > 0U)
+ {
+ *pStateCurnt++ = *pState++;
+ *pStateCurnt++ = *pState++;
+ *pStateCurnt++ = *pState++;
+ *pStateCurnt++ = *pState++;
+
+ tapCnt--;
+
+ }
+
+ /* Calculation of count for remaining q15_t data */
+ tapCnt = (numTaps - 1U) % 0x4U;
+
+ /* copy remaining data */
+ while (tapCnt > 0U)
+ {
+ *pStateCurnt++ = *pState++;
+
+ /* Decrement the loop counter */
+ tapCnt--;
+ }
+
+}
+
+/**
+ * @} end of FIR group
+ */
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