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Diffstat (limited to 'Drivers/CMSIS/DSP/Source/FilteringFunctions/arm_fir_lattice_f32.c')
| -rw-r--r-- | Drivers/CMSIS/DSP/Source/FilteringFunctions/arm_fir_lattice_f32.c | 453 |
1 files changed, 453 insertions, 0 deletions
diff --git a/Drivers/CMSIS/DSP/Source/FilteringFunctions/arm_fir_lattice_f32.c b/Drivers/CMSIS/DSP/Source/FilteringFunctions/arm_fir_lattice_f32.c new file mode 100644 index 0000000..8577fee --- /dev/null +++ b/Drivers/CMSIS/DSP/Source/FilteringFunctions/arm_fir_lattice_f32.c @@ -0,0 +1,453 @@ +/* ----------------------------------------------------------------------
+ * Project: CMSIS DSP Library
+ * Title: arm_fir_lattice_f32.c
+ * Description: Processing function for floating-point FIR Lattice filter
+ *
+ * $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
+ */
+
+/**
+ @defgroup FIR_Lattice Finite Impulse Response (FIR) Lattice Filters
+
+ This set of functions implements Finite Impulse Response (FIR) lattice filters
+ for Q15, Q31 and floating-point data types. Lattice filters are used in a
+ variety of adaptive filter applications. The filter structure is feedforward and
+ the net impulse response is finite length.
+ The functions operate on blocks
+ of input and output data and each call to the function processes
+ <code>blockSize</code> samples through the filter. <code>pSrc</code> and
+ <code>pDst</code> point to input and output arrays containing <code>blockSize</code> values.
+
+ @par Algorithm
+ \image html FIRLattice.gif "Finite Impulse Response Lattice filter"
+ The following difference equation is implemented:
+ @par
+ <pre>
+ f0[n] = g0[n] = x[n]
+ fm[n] = fm-1[n] + km * gm-1[n-1] for m = 1, 2, ...M
+ gm[n] = km * fm-1[n] + gm-1[n-1] for m = 1, 2, ...M
+ y[n] = fM[n]
+ </pre>
+ @par
+ <code>pCoeffs</code> points to tha array of reflection coefficients of size <code>numStages</code>.
+ Reflection Coefficients are stored in the following order.
+ @par
+ <pre>
+ {k1, k2, ..., kM}
+ </pre>
+ where M is number of stages
+ @par
+ <code>pState</code> points to a state array of size <code>numStages</code>.
+ The state variables (g values) hold previous inputs and are stored in the following order.
+ <pre>
+ {g0[n], g1[n], g2[n] ...gM-1[n]}
+ </pre>
+ The state variables are updated after each block of data is processed; the coefficients are untouched.
+
+ @par Instance Structure
+ The coefficients and state variables for a filter are stored together in an instance data structure.
+ A separate instance structure must be defined for each filter.
+ Coefficient arrays may be shared among several instances while state variable arrays cannot be shared.
+ There are separate instance structure declarations for each of the 3 supported data types.
+
+ @par Initialization Functions
+ There is also an associated initialization function for each data type.
+ The initialization function performs the following operations:
+ - Sets the values of the internal structure fields.
+ - Zeros out the values in the state buffer.
+ To do this manually without calling the init function, assign the follow subfields of the instance structure:
+ numStages, pCoeffs, pState. Also set all of the values in pState to zero.
+ @par
+ Use of the initialization function is optional.
+ However, if the initialization function is used, then the instance structure cannot be placed into a const data section.
+ To place an instance structure into a const data section, the instance structure must be manually initialized.
+ Set the values in the state buffer to zeros and then manually initialize the instance structure as follows:
+ <pre>
+ arm_fir_lattice_instance_f32 S = {numStages, pState, pCoeffs};
+ arm_fir_lattice_instance_q31 S = {numStages, pState, pCoeffs};
+ arm_fir_lattice_instance_q15 S = {numStages, pState, pCoeffs};
+ </pre>
+ @par
+ where <code>numStages</code> is the number of stages in the filter;
+ <code>pState</code> is the address of the state buffer;
+ <code>pCoeffs</code> is the address of the coefficient buffer.
+
+ @par Fixed-Point Behavior
+ Care must be taken when using the fixed-point versions of the FIR Lattice filter functions.
+ In particular, the overflow and saturation behavior of the accumulator used in each function must be considered.
+ Refer to the function specific documentation below for usage guidelines.
+ */
+
+/**
+ @addtogroup FIR_Lattice
+ @{
+ */
+
+/**
+ @brief Processing function for the floating-point FIR lattice filter.
+ @param[in] S points to an instance of the floating-point FIR lattice 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
+ @return none
+ */
+
+void arm_fir_lattice_f32(
+ const arm_fir_lattice_instance_f32 * S,
+ const float32_t * pSrc,
+ float32_t * pDst,
+ uint32_t blockSize)
+{
+ float32_t *pState = S->pState; /* State pointer */
+ const float32_t *pCoeffs = S->pCoeffs; /* Coefficient pointer */
+ float32_t *px; /* Temporary state pointer */
+ const float32_t *pk; /* Temporary coefficient pointer */
+ uint32_t numStages = S->numStages; /* Number of stages in the filter */
+ uint32_t blkCnt, stageCnt; /* Loop counters */
+ float32_t fcurr0, fnext0, gnext0, gcurr0; /* Temporary variables */
+
+#if defined (ARM_MATH_LOOPUNROLL)
+ float32_t fcurr1, fnext1, gnext1; /* Temporary variables for second sample in loop unrolling */
+ float32_t fcurr2, fnext2, gnext2; /* Temporary variables for third sample in loop unrolling */
+ float32_t fcurr3, fnext3, gnext3; /* Temporary variables for fourth sample in loop unrolling */
+#endif
+
+ gcurr0 = 0.0f;
+
+#if defined (ARM_MATH_LOOPUNROLL)
+
+ /* Loop unrolling: Compute 4 outputs at a time */
+ blkCnt = blockSize >> 2U;
+
+ while (blkCnt > 0U)
+ {
+ /* Read two samples from input buffer */
+ /* f0(n) = x(n) */
+ fcurr0 = *pSrc++;
+ fcurr1 = *pSrc++;
+
+ /* Initialize state pointer */
+ px = pState;
+
+ /* Initialize coeff pointer */
+ pk = pCoeffs;
+
+ /* Read g0(n-1) from state buffer */
+ gcurr0 = *px;
+
+ /* Process first sample for first tap */
+ /* f1(n) = f0(n) + K1 * g0(n-1) */
+ fnext0 = (gcurr0 * (*pk)) + fcurr0;
+
+ /* g1(n) = f0(n) * K1 + g0(n-1) */
+ gnext0 = (fcurr0 * (*pk)) + gcurr0;
+
+ /* Process second sample for first tap */
+ fnext1 = (fcurr0 * (*pk)) + fcurr1;
+ gnext1 = (fcurr1 * (*pk)) + fcurr0;
+
+ /* Read next two samples from input buffer */
+ /* f0(n+2) = x(n+2) */
+ fcurr2 = *pSrc++;
+ fcurr3 = *pSrc++;
+
+ /* Process third sample for first tap */
+ fnext2 = (fcurr1 * (*pk)) + fcurr2;
+ gnext2 = (fcurr2 * (*pk)) + fcurr1;
+
+ /* Process fourth sample for first tap */
+ fnext3 = (fcurr2 * (*pk )) + fcurr3;
+ gnext3 = (fcurr3 * (*pk++)) + fcurr2;
+
+ /* Copy only last input sample into the state buffer
+ which will be used for next samples processing */
+ *px++ = fcurr3;
+
+ /* Update of f values for next coefficient set processing */
+ fcurr0 = fnext0;
+ fcurr1 = fnext1;
+ fcurr2 = fnext2;
+ fcurr3 = fnext3;
+
+ /* Loop unrolling. Process 4 taps at a time . */
+ stageCnt = (numStages - 1U) >> 2U;
+
+ /* Loop over the number of taps. Unroll by a factor of 4.
+ Repeat until we've computed numStages-3 coefficients. */
+
+ /* Process 2nd, 3rd, 4th and 5th taps ... here */
+ while (stageCnt > 0U)
+ {
+ /* Read g1(n-1), g3(n-1) .... from state */
+ gcurr0 = *px;
+
+ /* save g1(n) in state buffer */
+ *px++ = gnext3;
+
+ /* Process first sample for 2nd, 6th .. tap */
+ /* Sample processing for K2, K6.... */
+ /* f2(n) = f1(n) + K2 * g1(n-1) */
+ fnext0 = (gcurr0 * (*pk)) + fcurr0;
+
+ /* Process second sample for 2nd, 6th .. tap */
+ /* for sample 2 processing */
+ fnext1 = (gnext0 * (*pk)) + fcurr1;
+
+ /* Process third sample for 2nd, 6th .. tap */
+ fnext2 = (gnext1 * (*pk)) + fcurr2;
+
+ /* Process fourth sample for 2nd, 6th .. tap */
+ fnext3 = (gnext2 * (*pk)) + fcurr3;
+
+ /* g2(n) = f1(n) * K2 + g1(n-1) */
+ /* Calculation of state values for next stage */
+ gnext3 = (fcurr3 * (*pk)) + gnext2;
+
+ gnext2 = (fcurr2 * (*pk)) + gnext1;
+
+ gnext1 = (fcurr1 * (*pk)) + gnext0;
+
+ gnext0 = (fcurr0 * (*pk++)) + gcurr0;
+
+
+ /* Read g2(n-1), g4(n-1) .... from state */
+ gcurr0 = *px;
+
+ /* save g2(n) in state buffer */
+ *px++ = gnext3;
+
+ /* Sample processing for K3, K7.... */
+ /* Process first sample for 3rd, 7th .. tap */
+ /* f3(n) = f2(n) + K3 * g2(n-1) */
+ fcurr0 = (gcurr0 * (*pk)) + fnext0;
+
+ /* Process second sample for 3rd, 7th .. tap */
+ fcurr1 = (gnext0 * (*pk)) + fnext1;
+
+ /* Process third sample for 3rd, 7th .. tap */
+ fcurr2 = (gnext1 * (*pk)) + fnext2;
+
+ /* Process fourth sample for 3rd, 7th .. tap */
+ fcurr3 = (gnext2 * (*pk)) + fnext3;
+
+ /* Calculation of state values for next stage */
+ /* g3(n) = f2(n) * K3 + g2(n-1) */
+ gnext3 = (fnext3 * (*pk)) + gnext2;
+
+ gnext2 = (fnext2 * (*pk)) + gnext1;
+
+ gnext1 = (fnext1 * (*pk)) + gnext0;
+
+ gnext0 = (fnext0 * (*pk++)) + gcurr0;
+
+
+ /* Read g1(n-1), g3(n-1) .... from state */
+ gcurr0 = *px;
+
+ /* save g3(n) in state buffer */
+ *px++ = gnext3;
+
+ /* Sample processing for K4, K8.... */
+ /* Process first sample for 4th, 8th .. tap */
+ /* f4(n) = f3(n) + K4 * g3(n-1) */
+ fnext0 = (gcurr0 * (*pk)) + fcurr0;
+
+ /* Process second sample for 4th, 8th .. tap */
+ /* for sample 2 processing */
+ fnext1 = (gnext0 * (*pk)) + fcurr1;
+
+ /* Process third sample for 4th, 8th .. tap */
+ fnext2 = (gnext1 * (*pk)) + fcurr2;
+
+ /* Process fourth sample for 4th, 8th .. tap */
+ fnext3 = (gnext2 * (*pk)) + fcurr3;
+
+ /* g4(n) = f3(n) * K4 + g3(n-1) */
+ /* Calculation of state values for next stage */
+ gnext3 = (fcurr3 * (*pk)) + gnext2;
+
+ gnext2 = (fcurr2 * (*pk)) + gnext1;
+
+ gnext1 = (fcurr1 * (*pk)) + gnext0;
+
+ gnext0 = (fcurr0 * (*pk++)) + gcurr0;
+
+
+ /* Read g2(n-1), g4(n-1) .... from state */
+ gcurr0 = *px;
+
+ /* save g4(n) in state buffer */
+ *px++ = gnext3;
+
+ /* Sample processing for K5, K9.... */
+ /* Process first sample for 5th, 9th .. tap */
+ /* f5(n) = f4(n) + K5 * g4(n-1) */
+ fcurr0 = (gcurr0 * (*pk)) + fnext0;
+
+ /* Process second sample for 5th, 9th .. tap */
+ fcurr1 = (gnext0 * (*pk)) + fnext1;
+
+ /* Process third sample for 5th, 9th .. tap */
+ fcurr2 = (gnext1 * (*pk)) + fnext2;
+
+ /* Process fourth sample for 5th, 9th .. tap */
+ fcurr3 = (gnext2 * (*pk)) + fnext3;
+
+ /* Calculation of state values for next stage */
+ /* g5(n) = f4(n) * K5 + g4(n-1) */
+ gnext3 = (fnext3 * (*pk)) + gnext2;
+
+ gnext2 = (fnext2 * (*pk)) + gnext1;
+
+ gnext1 = (fnext1 * (*pk)) + gnext0;
+
+ gnext0 = (fnext0 * (*pk++)) + gcurr0;
+
+ stageCnt--;
+ }
+
+ /* If the (filter length -1) is not a multiple of 4, compute the remaining filter taps */
+ stageCnt = (numStages - 1U) % 0x4U;
+
+ while (stageCnt > 0U)
+ {
+ gcurr0 = *px;
+
+ /* save g value in state buffer */
+ *px++ = gnext3;
+
+ /* Process four samples for last three taps here */
+ fnext0 = (gcurr0 * (*pk)) + fcurr0;
+
+ fnext1 = (gnext0 * (*pk)) + fcurr1;
+
+ fnext2 = (gnext1 * (*pk)) + fcurr2;
+
+ fnext3 = (gnext2 * (*pk)) + fcurr3;
+
+ /* g1(n) = f0(n) * K1 + g0(n-1) */
+ gnext3 = (fcurr3 * (*pk)) + gnext2;
+
+ gnext2 = (fcurr2 * (*pk)) + gnext1;
+
+ gnext1 = (fcurr1 * (*pk)) + gnext0;
+
+ gnext0 = (fcurr0 * (*pk++)) + gcurr0;
+
+ /* Update of f values for next coefficient set processing */
+ fcurr0 = fnext0;
+ fcurr1 = fnext1;
+ fcurr2 = fnext2;
+ fcurr3 = fnext3;
+
+ stageCnt--;
+ }
+
+ /* The results in the 4 accumulators, store in the destination buffer. */
+ /* y(n) = fN(n) */
+ *pDst++ = fcurr0;
+ *pDst++ = fcurr1;
+ *pDst++ = fcurr2;
+ *pDst++ = fcurr3;
+
+ blkCnt--;
+ }
+
+ /* Loop unrolling: Compute remaining outputs */
+ blkCnt = blockSize % 0x4U;
+
+#else
+
+ /* Initialize blkCnt with number of samples */
+ blkCnt = blockSize;
+
+#endif /* #if defined (ARM_MATH_LOOPUNROLL) */
+
+ while (blkCnt > 0U)
+ {
+ /* f0(n) = x(n) */
+ fcurr0 = *pSrc++;
+
+ /* Initialize state pointer */
+ px = pState;
+
+ /* Initialize coeff pointer */
+ pk = pCoeffs;
+
+ /* read g2(n) from state buffer */
+ gcurr0 = *px;
+
+ /* for sample 1 processing */
+ /* f1(n) = f0(n) + K1 * g0(n-1) */
+ fnext0 = (gcurr0 * (*pk)) + fcurr0;
+
+ /* g1(n) = f0(n) * K1 + g0(n-1) */
+ gnext0 = (fcurr0 * (*pk++)) + gcurr0;
+
+ /* save g1(n) in state buffer */
+ *px++ = fcurr0;
+
+ /* f1(n) is saved in fcurr0 for next stage processing */
+ fcurr0 = fnext0;
+
+ stageCnt = (numStages - 1U);
+
+ /* stage loop */
+ while (stageCnt > 0U)
+ {
+ /* read g2(n) from state buffer */
+ gcurr0 = *px;
+
+ /* save g1(n) in state buffer */
+ *px++ = gnext0;
+
+ /* Sample processing for K2, K3.... */
+ /* f2(n) = f1(n) + K2 * g1(n-1) */
+ fnext0 = (gcurr0 * (*pk)) + fcurr0;
+
+ /* g2(n) = f1(n) * K2 + g1(n-1) */
+ gnext0 = (fcurr0 * (*pk++)) + gcurr0;
+
+ /* f1(n) is saved in fcurr0 for next stage processing */
+ fcurr0 = fnext0;
+
+ stageCnt--;
+ }
+
+ /* y(n) = fN(n) */
+ *pDst++ = fcurr0;
+
+ blkCnt--;
+ }
+
+}
+
+/**
+ @} end of FIR_Lattice group
+ */
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