diff options
Diffstat (limited to 'fw/hid-dials/Drivers/CMSIS/DSP/Source/FilteringFunctions/arm_fir_q31.c')
| -rw-r--r-- | fw/hid-dials/Drivers/CMSIS/DSP/Source/FilteringFunctions/arm_fir_q31.c | 353 |
1 files changed, 353 insertions, 0 deletions
diff --git a/fw/hid-dials/Drivers/CMSIS/DSP/Source/FilteringFunctions/arm_fir_q31.c b/fw/hid-dials/Drivers/CMSIS/DSP/Source/FilteringFunctions/arm_fir_q31.c new file mode 100644 index 0000000..b0a2723 --- /dev/null +++ b/fw/hid-dials/Drivers/CMSIS/DSP/Source/FilteringFunctions/arm_fir_q31.c @@ -0,0 +1,353 @@ +/* ----------------------------------------------------------------------
+ * Project: CMSIS DSP Library
+ * Title: arm_fir_q31.c
+ * Description: Q31 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 Q31 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.
+ *
+ * @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.
+ * Thus, if the accumulator result overflows it wraps around rather than clip.
+ * In order to avoid overflows completely the input signal must be scaled down by log2(numTaps) bits.
+ * After all multiply-accumulates are performed, the 2.62 accumulator is right shifted by 31 bits and saturated to 1.31 format to yield the final result.
+ *
+ * \par
+ * Refer to the function <code>arm_fir_fast_q31()</code> for a faster but less precise implementation of this filter for Cortex-M3 and Cortex-M4.
+ */
+
+void arm_fir_q31(
+ const arm_fir_instance_q31 * S,
+ q31_t * pSrc,
+ q31_t * pDst,
+ uint32_t blockSize)
+{
+ q31_t *pState = S->pState; /* State pointer */
+ q31_t *pCoeffs = S->pCoeffs; /* Coefficient pointer */
+ q31_t *pStateCurnt; /* Points to the current sample of the state */
+
+
+#if defined (ARM_MATH_DSP)
+
+ /* Run the below code for Cortex-M4 and Cortex-M3 */
+
+ q31_t x0, x1, x2; /* Temporary variables to hold state */
+ q31_t c0; /* Temporary variable to hold coefficient value */
+ q31_t *px; /* Temporary pointer for state */
+ q31_t *pb; /* Temporary pointer for coefficient buffer */
+ q63_t acc0, acc1, acc2; /* Accumulators */
+ uint32_t numTaps = S->numTaps; /* Number of filter coefficients in the filter */
+ uint32_t i, tapCnt, blkCnt, tapCntN3; /* 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 / 3;
+ blockSize = blockSize - (3 * blkCnt);
+
+ tapCnt = numTaps / 3;
+ tapCntN3 = numTaps - (3 * tapCnt);
+
+ /* 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 three new input samples into the state buffer */
+ *pStateCurnt++ = *pSrc++;
+ *pStateCurnt++ = *pSrc++;
+ *pStateCurnt++ = *pSrc++;
+
+ /* Set all accumulators to zero */
+ acc0 = 0;
+ acc1 = 0;
+ acc2 = 0;
+
+ /* Initialize state pointer */
+ px = pState;
+
+ /* Initialize coefficient pointer */
+ pb = pCoeffs;
+
+ /* Read the first two samples from the state buffer:
+ * x[n-numTaps], x[n-numTaps-1] */
+ x0 = *(px++);
+ x1 = *(px++);
+
+ /* Loop unrolling. Process 3 taps at a time. */
+ i = tapCnt;
+
+ while (i > 0U)
+ {
+ /* Read the b[numTaps] coefficient */
+ c0 = *pb;
+
+ /* Read x[n-numTaps-2] sample */
+ x2 = *(px++);
+
+ /* Perform the multiply-accumulates */
+ acc0 += ((q63_t) x0 * c0);
+ acc1 += ((q63_t) x1 * c0);
+ acc2 += ((q63_t) x2 * c0);
+
+ /* Read the coefficient and state */
+ c0 = *(pb + 1U);
+ x0 = *(px++);
+
+ /* Perform the multiply-accumulates */
+ acc0 += ((q63_t) x1 * c0);
+ acc1 += ((q63_t) x2 * c0);
+ acc2 += ((q63_t) x0 * c0);
+
+ /* Read the coefficient and state */
+ c0 = *(pb + 2U);
+ x1 = *(px++);
+
+ /* update coefficient pointer */
+ pb += 3U;
+
+ /* Perform the multiply-accumulates */
+ acc0 += ((q63_t) x2 * c0);
+ acc1 += ((q63_t) x0 * c0);
+ acc2 += ((q63_t) x1 * c0);
+
+ /* Decrement the loop counter */
+ i--;
+ }
+
+ /* If the filter length is not a multiple of 3, compute the remaining filter taps */
+
+ i = tapCntN3;
+
+ while (i > 0U)
+ {
+ /* Read coefficients */
+ c0 = *(pb++);
+
+ /* Fetch 1 state variable */
+ x2 = *(px++);
+
+ /* Perform the multiply-accumulates */
+ acc0 += ((q63_t) x0 * c0);
+ acc1 += ((q63_t) x1 * c0);
+ acc2 += ((q63_t) x2 * c0);
+
+ /* Reuse the present sample states for next sample */
+ x0 = x1;
+ x1 = x2;
+
+ /* Decrement the loop counter */
+ i--;
+ }
+
+ /* Advance the state pointer by 3 to process the next group of 3 samples */
+ pState = pState + 3;
+
+ /* The results in the 3 accumulators are in 2.30 format. Convert to 1.31
+ ** Then store the 3 outputs in the destination buffer. */
+ *pDst++ = (q31_t) (acc0 >> 31U);
+ *pDst++ = (q31_t) (acc1 >> 31U);
+ *pDst++ = (q31_t) (acc2 >> 31U);
+
+ /* Decrement the samples loop counter */
+ blkCnt--;
+ }
+
+ /* If the blockSize is not a multiple of 3, compute any remaining output samples here.
+ ** No loop unrolling is used. */
+
+ while (blockSize > 0U)
+ {
+ /* Copy one sample at a time into state buffer */
+ *pStateCurnt++ = *pSrc++;
+
+ /* Set the accumulator to zero */
+ acc0 = 0;
+
+ /* Initialize state pointer */
+ px = pState;
+
+ /* Initialize Coefficient pointer */
+ pb = (pCoeffs);
+
+ i = numTaps;
+
+ /* Perform the multiply-accumulates */
+ do
+ {
+ acc0 += (q63_t) * (px++) * (*(pb++));
+ i--;
+ } while (i > 0U);
+
+ /* The result is in 2.62 format. Convert to 1.31
+ ** Then store the output in the destination buffer. */
+ *pDst++ = (q31_t) (acc0 >> 31U);
+
+ /* Advance state pointer by 1 for the next sample */
+ pState = pState + 1;
+
+ /* Decrement the samples loop counter */
+ blockSize--;
+ }
+
+ /* 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;
+
+ tapCnt = (numTaps - 1U) >> 2U;
+
+ /* copy data */
+ while (tapCnt > 0U)
+ {
+ *pStateCurnt++ = *pState++;
+ *pStateCurnt++ = *pState++;
+ *pStateCurnt++ = *pState++;
+ *pStateCurnt++ = *pState++;
+
+ /* Decrement the loop counter */
+ tapCnt--;
+ }
+
+ /* Calculate remaining number of copies */
+ tapCnt = (numTaps - 1U) % 0x4U;
+
+ /* Copy the remaining q31_t data */
+ while (tapCnt > 0U)
+ {
+ *pStateCurnt++ = *pState++;
+
+ /* Decrement the loop counter */
+ tapCnt--;
+ }
+
+#else
+
+/* Run the below code for Cortex-M0 */
+
+ q31_t *px; /* Temporary pointer for state */
+ q31_t *pb; /* Temporary pointer for coefficient buffer */
+ q63_t acc; /* Accumulator */
+ uint32_t numTaps = S->numTaps; /* Length of the filter */
+ uint32_t i, tapCnt, blkCnt; /* Loop counters */
+
+ /* S->pState buffer contains previous frame (numTaps - 1) samples */
+ /* pStateCurnt points to the location where the new input data should be written */
+ pStateCurnt = &(S->pState[(numTaps - 1U)]);
+
+ /* Initialize blkCnt with blockSize */
+ blkCnt = blockSize;
+
+ while (blkCnt > 0U)
+ {
+ /* Copy one sample at a time into state buffer */
+ *pStateCurnt++ = *pSrc++;
+
+ /* Set the accumulator to zero */
+ acc = 0;
+
+ /* Initialize state pointer */
+ px = pState;
+
+ /* Initialize Coefficient pointer */
+ pb = pCoeffs;
+
+ i = numTaps;
+
+ /* Perform the multiply-accumulates */
+ do
+ {
+ /* acc = 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] */
+ acc += (q63_t) * px++ * *pb++;
+ i--;
+ } while (i > 0U);
+
+ /* The result is in 2.62 format. Convert to 1.31
+ ** Then store the output in the destination buffer. */
+ *pDst++ = (q31_t) (acc >> 31U);
+
+ /* Advance state pointer by 1 for the next sample */
+ pState = pState + 1;
+
+ /* Decrement the samples loop counter */
+ blkCnt--;
+ }
+
+ /* Processing is complete.
+ ** Now copy the last numTaps - 1 samples to the starting 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;
+
+ /* Copy numTaps number of values */
+ tapCnt = numTaps - 1U;
+
+ /* Copy the data */
+ while (tapCnt > 0U)
+ {
+ *pStateCurnt++ = *pState++;
+
+ /* Decrement the loop counter */
+ tapCnt--;
+ }
+
+
+#endif /* #if defined (ARM_MATH_DSP) */
+
+}
+
+/**
+ * @} end of FIR group
+ */
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