CMSIS DSP library
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Fork of mbed-dsp by
cmsis_dsp/FilteringFunctions/arm_fir_f32.c@1:fdd22bb7aa52, 2012-11-28 (annotated)
- Committer:
- emilmont
- Date:
- Wed Nov 28 12:30:09 2012 +0000
- Revision:
- 1:fdd22bb7aa52
- Child:
- 2:da51fb522205
DSP library code
Who changed what in which revision?
User | Revision | Line number | New contents of line |
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emilmont | 1:fdd22bb7aa52 | 1 | /* ---------------------------------------------------------------------- |
emilmont | 1:fdd22bb7aa52 | 2 | * Copyright (C) 2010 ARM Limited. All rights reserved. |
emilmont | 1:fdd22bb7aa52 | 3 | * |
emilmont | 1:fdd22bb7aa52 | 4 | * $Date: 15. February 2012 |
emilmont | 1:fdd22bb7aa52 | 5 | * $Revision: V1.1.0 |
emilmont | 1:fdd22bb7aa52 | 6 | * |
emilmont | 1:fdd22bb7aa52 | 7 | * Project: CMSIS DSP Library |
emilmont | 1:fdd22bb7aa52 | 8 | * Title: arm_fir_f32.c |
emilmont | 1:fdd22bb7aa52 | 9 | * |
emilmont | 1:fdd22bb7aa52 | 10 | * Description: Floating-point FIR filter processing function. |
emilmont | 1:fdd22bb7aa52 | 11 | * |
emilmont | 1:fdd22bb7aa52 | 12 | * Target Processor: Cortex-M4/Cortex-M3/Cortex-M0 |
emilmont | 1:fdd22bb7aa52 | 13 | * |
emilmont | 1:fdd22bb7aa52 | 14 | * Version 1.1.0 2012/02/15 |
emilmont | 1:fdd22bb7aa52 | 15 | * Updated with more optimizations, bug fixes and minor API changes. |
emilmont | 1:fdd22bb7aa52 | 16 | * |
emilmont | 1:fdd22bb7aa52 | 17 | * Version 1.0.2 2010/11/11 |
emilmont | 1:fdd22bb7aa52 | 18 | * Documentation updated. |
emilmont | 1:fdd22bb7aa52 | 19 | * |
emilmont | 1:fdd22bb7aa52 | 20 | * Version 1.0.1 2010/10/05 |
emilmont | 1:fdd22bb7aa52 | 21 | * Production release and review comments incorporated. |
emilmont | 1:fdd22bb7aa52 | 22 | * |
emilmont | 1:fdd22bb7aa52 | 23 | * Version 1.0.0 2010/09/20 |
emilmont | 1:fdd22bb7aa52 | 24 | * Production release and review comments incorporated. |
emilmont | 1:fdd22bb7aa52 | 25 | * |
emilmont | 1:fdd22bb7aa52 | 26 | * Version 0.0.5 2010/04/26 |
emilmont | 1:fdd22bb7aa52 | 27 | * incorporated review comments and updated with latest CMSIS layer |
emilmont | 1:fdd22bb7aa52 | 28 | * |
emilmont | 1:fdd22bb7aa52 | 29 | * Version 0.0.3 2010/03/10 |
emilmont | 1:fdd22bb7aa52 | 30 | * Initial version |
emilmont | 1:fdd22bb7aa52 | 31 | * -------------------------------------------------------------------- */ |
emilmont | 1:fdd22bb7aa52 | 32 | |
emilmont | 1:fdd22bb7aa52 | 33 | #include "arm_math.h" |
emilmont | 1:fdd22bb7aa52 | 34 | |
emilmont | 1:fdd22bb7aa52 | 35 | /** |
emilmont | 1:fdd22bb7aa52 | 36 | * @ingroup groupFilters |
emilmont | 1:fdd22bb7aa52 | 37 | */ |
emilmont | 1:fdd22bb7aa52 | 38 | |
emilmont | 1:fdd22bb7aa52 | 39 | /** |
emilmont | 1:fdd22bb7aa52 | 40 | * @defgroup FIR Finite Impulse Response (FIR) Filters |
emilmont | 1:fdd22bb7aa52 | 41 | * |
emilmont | 1:fdd22bb7aa52 | 42 | * This set of functions implements Finite Impulse Response (FIR) filters |
emilmont | 1:fdd22bb7aa52 | 43 | * for Q7, Q15, Q31, and floating-point data types. Fast versions of Q15 and Q31 are also provided. |
emilmont | 1:fdd22bb7aa52 | 44 | * The functions operate on blocks of input and output data and each call to the function processes |
emilmont | 1:fdd22bb7aa52 | 45 | * <code>blockSize</code> samples through the filter. <code>pSrc</code> and |
emilmont | 1:fdd22bb7aa52 | 46 | * <code>pDst</code> points to input and output arrays containing <code>blockSize</code> values. |
emilmont | 1:fdd22bb7aa52 | 47 | * |
emilmont | 1:fdd22bb7aa52 | 48 | * \par Algorithm: |
emilmont | 1:fdd22bb7aa52 | 49 | * The FIR filter algorithm is based upon a sequence of multiply-accumulate (MAC) operations. |
emilmont | 1:fdd22bb7aa52 | 50 | * Each filter coefficient <code>b[n]</code> is multiplied by a state variable which equals a previous input sample <code>x[n]</code>. |
emilmont | 1:fdd22bb7aa52 | 51 | * <pre> |
emilmont | 1:fdd22bb7aa52 | 52 | * y[n] = b[0] * x[n] + b[1] * x[n-1] + b[2] * x[n-2] + ...+ b[numTaps-1] * x[n-numTaps+1] |
emilmont | 1:fdd22bb7aa52 | 53 | * </pre> |
emilmont | 1:fdd22bb7aa52 | 54 | * \par |
emilmont | 1:fdd22bb7aa52 | 55 | * \image html FIR.gif "Finite Impulse Response filter" |
emilmont | 1:fdd22bb7aa52 | 56 | * \par |
emilmont | 1:fdd22bb7aa52 | 57 | * <code>pCoeffs</code> points to a coefficient array of size <code>numTaps</code>. |
emilmont | 1:fdd22bb7aa52 | 58 | * Coefficients are stored in time reversed order. |
emilmont | 1:fdd22bb7aa52 | 59 | * \par |
emilmont | 1:fdd22bb7aa52 | 60 | * <pre> |
emilmont | 1:fdd22bb7aa52 | 61 | * {b[numTaps-1], b[numTaps-2], b[N-2], ..., b[1], b[0]} |
emilmont | 1:fdd22bb7aa52 | 62 | * </pre> |
emilmont | 1:fdd22bb7aa52 | 63 | * \par |
emilmont | 1:fdd22bb7aa52 | 64 | * <code>pState</code> points to a state array of size <code>numTaps + blockSize - 1</code>. |
emilmont | 1:fdd22bb7aa52 | 65 | * Samples in the state buffer are stored in the following order. |
emilmont | 1:fdd22bb7aa52 | 66 | * \par |
emilmont | 1:fdd22bb7aa52 | 67 | * <pre> |
emilmont | 1:fdd22bb7aa52 | 68 | * {x[n-numTaps+1], x[n-numTaps], x[n-numTaps-1], x[n-numTaps-2]....x[0], x[1], ..., x[blockSize-1]} |
emilmont | 1:fdd22bb7aa52 | 69 | * </pre> |
emilmont | 1:fdd22bb7aa52 | 70 | * \par |
emilmont | 1:fdd22bb7aa52 | 71 | * Note that the length of the state buffer exceeds the length of the coefficient array by <code>blockSize-1</code>. |
emilmont | 1:fdd22bb7aa52 | 72 | * The increased state buffer length allows circular addressing, which is traditionally used in the FIR filters, |
emilmont | 1:fdd22bb7aa52 | 73 | * to be avoided and yields a significant speed improvement. |
emilmont | 1:fdd22bb7aa52 | 74 | * The state variables are updated after each block of data is processed; the coefficients are untouched. |
emilmont | 1:fdd22bb7aa52 | 75 | * \par Instance Structure |
emilmont | 1:fdd22bb7aa52 | 76 | * The coefficients and state variables for a filter are stored together in an instance data structure. |
emilmont | 1:fdd22bb7aa52 | 77 | * A separate instance structure must be defined for each filter. |
emilmont | 1:fdd22bb7aa52 | 78 | * Coefficient arrays may be shared among several instances while state variable arrays cannot be shared. |
emilmont | 1:fdd22bb7aa52 | 79 | * There are separate instance structure declarations for each of the 4 supported data types. |
emilmont | 1:fdd22bb7aa52 | 80 | * |
emilmont | 1:fdd22bb7aa52 | 81 | * \par Initialization Functions |
emilmont | 1:fdd22bb7aa52 | 82 | * There is also an associated initialization function for each data type. |
emilmont | 1:fdd22bb7aa52 | 83 | * The initialization function performs the following operations: |
emilmont | 1:fdd22bb7aa52 | 84 | * - Sets the values of the internal structure fields. |
emilmont | 1:fdd22bb7aa52 | 85 | * - Zeros out the values in the state buffer. |
emilmont | 1:fdd22bb7aa52 | 86 | * |
emilmont | 1:fdd22bb7aa52 | 87 | * \par |
emilmont | 1:fdd22bb7aa52 | 88 | * Use of the initialization function is optional. |
emilmont | 1:fdd22bb7aa52 | 89 | * However, if the initialization function is used, then the instance structure cannot be placed into a const data section. |
emilmont | 1:fdd22bb7aa52 | 90 | * To place an instance structure into a const data section, the instance structure must be manually initialized. |
emilmont | 1:fdd22bb7aa52 | 91 | * Set the values in the state buffer to zeros before static initialization. |
emilmont | 1:fdd22bb7aa52 | 92 | * The code below statically initializes each of the 4 different data type filter instance structures |
emilmont | 1:fdd22bb7aa52 | 93 | * <pre> |
emilmont | 1:fdd22bb7aa52 | 94 | *arm_fir_instance_f32 S = {numTaps, pState, pCoeffs}; |
emilmont | 1:fdd22bb7aa52 | 95 | *arm_fir_instance_q31 S = {numTaps, pState, pCoeffs}; |
emilmont | 1:fdd22bb7aa52 | 96 | *arm_fir_instance_q15 S = {numTaps, pState, pCoeffs}; |
emilmont | 1:fdd22bb7aa52 | 97 | *arm_fir_instance_q7 S = {numTaps, pState, pCoeffs}; |
emilmont | 1:fdd22bb7aa52 | 98 | * </pre> |
emilmont | 1:fdd22bb7aa52 | 99 | * |
emilmont | 1:fdd22bb7aa52 | 100 | * where <code>numTaps</code> is the number of filter coefficients in the filter; <code>pState</code> is the address of the state buffer; |
emilmont | 1:fdd22bb7aa52 | 101 | * <code>pCoeffs</code> is the address of the coefficient buffer. |
emilmont | 1:fdd22bb7aa52 | 102 | * |
emilmont | 1:fdd22bb7aa52 | 103 | * \par Fixed-Point Behavior |
emilmont | 1:fdd22bb7aa52 | 104 | * Care must be taken when using the fixed-point versions of the FIR filter functions. |
emilmont | 1:fdd22bb7aa52 | 105 | * In particular, the overflow and saturation behavior of the accumulator used in each function must be considered. |
emilmont | 1:fdd22bb7aa52 | 106 | * Refer to the function specific documentation below for usage guidelines. |
emilmont | 1:fdd22bb7aa52 | 107 | */ |
emilmont | 1:fdd22bb7aa52 | 108 | |
emilmont | 1:fdd22bb7aa52 | 109 | /** |
emilmont | 1:fdd22bb7aa52 | 110 | * @addtogroup FIR |
emilmont | 1:fdd22bb7aa52 | 111 | * @{ |
emilmont | 1:fdd22bb7aa52 | 112 | */ |
emilmont | 1:fdd22bb7aa52 | 113 | |
emilmont | 1:fdd22bb7aa52 | 114 | /** |
emilmont | 1:fdd22bb7aa52 | 115 | * |
emilmont | 1:fdd22bb7aa52 | 116 | * @param[in] *S points to an instance of the floating-point FIR filter structure. |
emilmont | 1:fdd22bb7aa52 | 117 | * @param[in] *pSrc points to the block of input data. |
emilmont | 1:fdd22bb7aa52 | 118 | * @param[out] *pDst points to the block of output data. |
emilmont | 1:fdd22bb7aa52 | 119 | * @param[in] blockSize number of samples to process per call. |
emilmont | 1:fdd22bb7aa52 | 120 | * @return none. |
emilmont | 1:fdd22bb7aa52 | 121 | * |
emilmont | 1:fdd22bb7aa52 | 122 | */ |
emilmont | 1:fdd22bb7aa52 | 123 | |
emilmont | 1:fdd22bb7aa52 | 124 | #ifndef ARM_MATH_CM0 |
emilmont | 1:fdd22bb7aa52 | 125 | |
emilmont | 1:fdd22bb7aa52 | 126 | /* Run the below code for Cortex-M4 and Cortex-M3 */ |
emilmont | 1:fdd22bb7aa52 | 127 | |
emilmont | 1:fdd22bb7aa52 | 128 | void arm_fir_f32( |
emilmont | 1:fdd22bb7aa52 | 129 | const arm_fir_instance_f32 * S, |
emilmont | 1:fdd22bb7aa52 | 130 | float32_t * pSrc, |
emilmont | 1:fdd22bb7aa52 | 131 | float32_t * pDst, |
emilmont | 1:fdd22bb7aa52 | 132 | uint32_t blockSize) |
emilmont | 1:fdd22bb7aa52 | 133 | { |
emilmont | 1:fdd22bb7aa52 | 134 | float32_t *pState = S->pState; /* State pointer */ |
emilmont | 1:fdd22bb7aa52 | 135 | float32_t *pCoeffs = S->pCoeffs; /* Coefficient pointer */ |
emilmont | 1:fdd22bb7aa52 | 136 | float32_t *pStateCurnt; /* Points to the current sample of the state */ |
emilmont | 1:fdd22bb7aa52 | 137 | float32_t *px, *pb; /* Temporary pointers for state and coefficient buffers */ |
emilmont | 1:fdd22bb7aa52 | 138 | float32_t acc0, acc1, acc2, acc3, acc4, acc5, acc6, acc7; /* Accumulators */ |
emilmont | 1:fdd22bb7aa52 | 139 | float32_t x0, x1, x2, x3, x4, x5, x6, x7, c0; /* Temporary variables to hold state and coefficient values */ |
emilmont | 1:fdd22bb7aa52 | 140 | uint32_t numTaps = S->numTaps; /* Number of filter coefficients in the filter */ |
emilmont | 1:fdd22bb7aa52 | 141 | uint32_t i, tapCnt, blkCnt; /* Loop counters */ |
emilmont | 1:fdd22bb7aa52 | 142 | |
emilmont | 1:fdd22bb7aa52 | 143 | /* S->pState points to state array which contains previous frame (numTaps - 1) samples */ |
emilmont | 1:fdd22bb7aa52 | 144 | /* pStateCurnt points to the location where the new input data should be written */ |
emilmont | 1:fdd22bb7aa52 | 145 | pStateCurnt = &(S->pState[(numTaps - 1u)]); |
emilmont | 1:fdd22bb7aa52 | 146 | |
emilmont | 1:fdd22bb7aa52 | 147 | /* Apply loop unrolling and compute 4 output values simultaneously. |
emilmont | 1:fdd22bb7aa52 | 148 | * The variables acc0 ... acc3 hold output values that are being computed: |
emilmont | 1:fdd22bb7aa52 | 149 | * |
emilmont | 1:fdd22bb7aa52 | 150 | * 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] |
emilmont | 1:fdd22bb7aa52 | 151 | * 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] |
emilmont | 1:fdd22bb7aa52 | 152 | * 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] |
emilmont | 1:fdd22bb7aa52 | 153 | * 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] |
emilmont | 1:fdd22bb7aa52 | 154 | */ |
emilmont | 1:fdd22bb7aa52 | 155 | blkCnt = blockSize >> 3; |
emilmont | 1:fdd22bb7aa52 | 156 | |
emilmont | 1:fdd22bb7aa52 | 157 | /* First part of the processing with loop unrolling. Compute 4 outputs at a time. |
emilmont | 1:fdd22bb7aa52 | 158 | ** a second loop below computes the remaining 1 to 3 samples. */ |
emilmont | 1:fdd22bb7aa52 | 159 | while(blkCnt > 0u) |
emilmont | 1:fdd22bb7aa52 | 160 | { |
emilmont | 1:fdd22bb7aa52 | 161 | /* Copy four new input samples into the state buffer */ |
emilmont | 1:fdd22bb7aa52 | 162 | *pStateCurnt++ = *pSrc++; |
emilmont | 1:fdd22bb7aa52 | 163 | *pStateCurnt++ = *pSrc++; |
emilmont | 1:fdd22bb7aa52 | 164 | *pStateCurnt++ = *pSrc++; |
emilmont | 1:fdd22bb7aa52 | 165 | *pStateCurnt++ = *pSrc++; |
emilmont | 1:fdd22bb7aa52 | 166 | *pStateCurnt++ = *pSrc++; |
emilmont | 1:fdd22bb7aa52 | 167 | *pStateCurnt++ = *pSrc++; |
emilmont | 1:fdd22bb7aa52 | 168 | *pStateCurnt++ = *pSrc++; |
emilmont | 1:fdd22bb7aa52 | 169 | *pStateCurnt++ = *pSrc++; |
emilmont | 1:fdd22bb7aa52 | 170 | |
emilmont | 1:fdd22bb7aa52 | 171 | /* Set all accumulators to zero */ |
emilmont | 1:fdd22bb7aa52 | 172 | acc0 = 0.0f; |
emilmont | 1:fdd22bb7aa52 | 173 | acc1 = 0.0f; |
emilmont | 1:fdd22bb7aa52 | 174 | acc2 = 0.0f; |
emilmont | 1:fdd22bb7aa52 | 175 | acc3 = 0.0f; |
emilmont | 1:fdd22bb7aa52 | 176 | acc4 = 0.0f; |
emilmont | 1:fdd22bb7aa52 | 177 | acc5 = 0.0f; |
emilmont | 1:fdd22bb7aa52 | 178 | acc6 = 0.0f; |
emilmont | 1:fdd22bb7aa52 | 179 | acc7 = 0.0f; |
emilmont | 1:fdd22bb7aa52 | 180 | |
emilmont | 1:fdd22bb7aa52 | 181 | /* Initialize state pointer */ |
emilmont | 1:fdd22bb7aa52 | 182 | px = pState; |
emilmont | 1:fdd22bb7aa52 | 183 | |
emilmont | 1:fdd22bb7aa52 | 184 | /* Initialize coeff pointer */ |
emilmont | 1:fdd22bb7aa52 | 185 | pb = (pCoeffs); |
emilmont | 1:fdd22bb7aa52 | 186 | |
emilmont | 1:fdd22bb7aa52 | 187 | /* Read the first three samples from the state buffer: x[n-numTaps], x[n-numTaps-1], x[n-numTaps-2] */ |
emilmont | 1:fdd22bb7aa52 | 188 | x0 = *px++; |
emilmont | 1:fdd22bb7aa52 | 189 | x1 = *px++; |
emilmont | 1:fdd22bb7aa52 | 190 | x2 = *px++; |
emilmont | 1:fdd22bb7aa52 | 191 | x3 = *px++; |
emilmont | 1:fdd22bb7aa52 | 192 | x4 = *px++; |
emilmont | 1:fdd22bb7aa52 | 193 | x5 = *px++; |
emilmont | 1:fdd22bb7aa52 | 194 | x6 = *px++; |
emilmont | 1:fdd22bb7aa52 | 195 | |
emilmont | 1:fdd22bb7aa52 | 196 | /* Loop unrolling. Process 4 taps at a time. */ |
emilmont | 1:fdd22bb7aa52 | 197 | tapCnt = numTaps >> 3u; |
emilmont | 1:fdd22bb7aa52 | 198 | |
emilmont | 1:fdd22bb7aa52 | 199 | /* Loop over the number of taps. Unroll by a factor of 4. |
emilmont | 1:fdd22bb7aa52 | 200 | ** Repeat until we've computed numTaps-4 coefficients. */ |
emilmont | 1:fdd22bb7aa52 | 201 | while(tapCnt > 0u) |
emilmont | 1:fdd22bb7aa52 | 202 | { |
emilmont | 1:fdd22bb7aa52 | 203 | /* Read the b[numTaps-1] coefficient */ |
emilmont | 1:fdd22bb7aa52 | 204 | c0 = *(pb++); |
emilmont | 1:fdd22bb7aa52 | 205 | |
emilmont | 1:fdd22bb7aa52 | 206 | /* Read x[n-numTaps-3] sample */ |
emilmont | 1:fdd22bb7aa52 | 207 | x7 = *(px++); |
emilmont | 1:fdd22bb7aa52 | 208 | |
emilmont | 1:fdd22bb7aa52 | 209 | /* acc0 += b[numTaps-1] * x[n-numTaps] */ |
emilmont | 1:fdd22bb7aa52 | 210 | acc0 += x0 * c0; |
emilmont | 1:fdd22bb7aa52 | 211 | |
emilmont | 1:fdd22bb7aa52 | 212 | /* acc1 += b[numTaps-1] * x[n-numTaps-1] */ |
emilmont | 1:fdd22bb7aa52 | 213 | acc1 += x1 * c0; |
emilmont | 1:fdd22bb7aa52 | 214 | |
emilmont | 1:fdd22bb7aa52 | 215 | /* acc2 += b[numTaps-1] * x[n-numTaps-2] */ |
emilmont | 1:fdd22bb7aa52 | 216 | acc2 += x2 * c0; |
emilmont | 1:fdd22bb7aa52 | 217 | |
emilmont | 1:fdd22bb7aa52 | 218 | /* acc3 += b[numTaps-1] * x[n-numTaps-3] */ |
emilmont | 1:fdd22bb7aa52 | 219 | acc3 += x3 * c0; |
emilmont | 1:fdd22bb7aa52 | 220 | |
emilmont | 1:fdd22bb7aa52 | 221 | /* acc4 += b[numTaps-1] * x[n-numTaps-4] */ |
emilmont | 1:fdd22bb7aa52 | 222 | acc4 += x4 * c0; |
emilmont | 1:fdd22bb7aa52 | 223 | |
emilmont | 1:fdd22bb7aa52 | 224 | /* acc1 += b[numTaps-1] * x[n-numTaps-5] */ |
emilmont | 1:fdd22bb7aa52 | 225 | acc5 += x5 * c0; |
emilmont | 1:fdd22bb7aa52 | 226 | |
emilmont | 1:fdd22bb7aa52 | 227 | /* acc2 += b[numTaps-1] * x[n-numTaps-6] */ |
emilmont | 1:fdd22bb7aa52 | 228 | acc6 += x6 * c0; |
emilmont | 1:fdd22bb7aa52 | 229 | |
emilmont | 1:fdd22bb7aa52 | 230 | /* acc3 += b[numTaps-1] * x[n-numTaps-7] */ |
emilmont | 1:fdd22bb7aa52 | 231 | acc7 += x7 * c0; |
emilmont | 1:fdd22bb7aa52 | 232 | |
emilmont | 1:fdd22bb7aa52 | 233 | /* Read the b[numTaps-2] coefficient */ |
emilmont | 1:fdd22bb7aa52 | 234 | c0 = *(pb++); |
emilmont | 1:fdd22bb7aa52 | 235 | |
emilmont | 1:fdd22bb7aa52 | 236 | /* Read x[n-numTaps-4] sample */ |
emilmont | 1:fdd22bb7aa52 | 237 | x0 = *(px++); |
emilmont | 1:fdd22bb7aa52 | 238 | |
emilmont | 1:fdd22bb7aa52 | 239 | /* Perform the multiply-accumulate */ |
emilmont | 1:fdd22bb7aa52 | 240 | acc0 += x1 * c0; |
emilmont | 1:fdd22bb7aa52 | 241 | acc1 += x2 * c0; |
emilmont | 1:fdd22bb7aa52 | 242 | acc2 += x3 * c0; |
emilmont | 1:fdd22bb7aa52 | 243 | acc3 += x4 * c0; |
emilmont | 1:fdd22bb7aa52 | 244 | acc4 += x5 * c0; |
emilmont | 1:fdd22bb7aa52 | 245 | acc5 += x6 * c0; |
emilmont | 1:fdd22bb7aa52 | 246 | acc6 += x7 * c0; |
emilmont | 1:fdd22bb7aa52 | 247 | acc7 += x0 * c0; |
emilmont | 1:fdd22bb7aa52 | 248 | |
emilmont | 1:fdd22bb7aa52 | 249 | /* Read the b[numTaps-3] coefficient */ |
emilmont | 1:fdd22bb7aa52 | 250 | c0 = *(pb++); |
emilmont | 1:fdd22bb7aa52 | 251 | |
emilmont | 1:fdd22bb7aa52 | 252 | /* Read x[n-numTaps-5] sample */ |
emilmont | 1:fdd22bb7aa52 | 253 | x1 = *(px++); |
emilmont | 1:fdd22bb7aa52 | 254 | |
emilmont | 1:fdd22bb7aa52 | 255 | /* Perform the multiply-accumulates */ |
emilmont | 1:fdd22bb7aa52 | 256 | acc0 += x2 * c0; |
emilmont | 1:fdd22bb7aa52 | 257 | acc1 += x3 * c0; |
emilmont | 1:fdd22bb7aa52 | 258 | acc2 += x4 * c0; |
emilmont | 1:fdd22bb7aa52 | 259 | acc3 += x5 * c0; |
emilmont | 1:fdd22bb7aa52 | 260 | acc4 += x6 * c0; |
emilmont | 1:fdd22bb7aa52 | 261 | acc5 += x7 * c0; |
emilmont | 1:fdd22bb7aa52 | 262 | acc6 += x0 * c0; |
emilmont | 1:fdd22bb7aa52 | 263 | acc7 += x1 * c0; |
emilmont | 1:fdd22bb7aa52 | 264 | |
emilmont | 1:fdd22bb7aa52 | 265 | /* Read the b[numTaps-4] coefficient */ |
emilmont | 1:fdd22bb7aa52 | 266 | c0 = *(pb++); |
emilmont | 1:fdd22bb7aa52 | 267 | |
emilmont | 1:fdd22bb7aa52 | 268 | /* Read x[n-numTaps-6] sample */ |
emilmont | 1:fdd22bb7aa52 | 269 | x2 = *(px++); |
emilmont | 1:fdd22bb7aa52 | 270 | |
emilmont | 1:fdd22bb7aa52 | 271 | /* Perform the multiply-accumulates */ |
emilmont | 1:fdd22bb7aa52 | 272 | acc0 += x3 * c0; |
emilmont | 1:fdd22bb7aa52 | 273 | acc1 += x4 * c0; |
emilmont | 1:fdd22bb7aa52 | 274 | acc2 += x5 * c0; |
emilmont | 1:fdd22bb7aa52 | 275 | acc3 += x6 * c0; |
emilmont | 1:fdd22bb7aa52 | 276 | acc4 += x7 * c0; |
emilmont | 1:fdd22bb7aa52 | 277 | acc5 += x0 * c0; |
emilmont | 1:fdd22bb7aa52 | 278 | acc6 += x1 * c0; |
emilmont | 1:fdd22bb7aa52 | 279 | acc7 += x2 * c0; |
emilmont | 1:fdd22bb7aa52 | 280 | |
emilmont | 1:fdd22bb7aa52 | 281 | /* Read the b[numTaps-4] coefficient */ |
emilmont | 1:fdd22bb7aa52 | 282 | c0 = *(pb++); |
emilmont | 1:fdd22bb7aa52 | 283 | |
emilmont | 1:fdd22bb7aa52 | 284 | /* Read x[n-numTaps-6] sample */ |
emilmont | 1:fdd22bb7aa52 | 285 | x3 = *(px++); |
emilmont | 1:fdd22bb7aa52 | 286 | |
emilmont | 1:fdd22bb7aa52 | 287 | /* Perform the multiply-accumulates */ |
emilmont | 1:fdd22bb7aa52 | 288 | acc0 += x4 * c0; |
emilmont | 1:fdd22bb7aa52 | 289 | acc1 += x5 * c0; |
emilmont | 1:fdd22bb7aa52 | 290 | acc2 += x6 * c0; |
emilmont | 1:fdd22bb7aa52 | 291 | acc3 += x7 * c0; |
emilmont | 1:fdd22bb7aa52 | 292 | acc4 += x0 * c0; |
emilmont | 1:fdd22bb7aa52 | 293 | acc5 += x1 * c0; |
emilmont | 1:fdd22bb7aa52 | 294 | acc6 += x2 * c0; |
emilmont | 1:fdd22bb7aa52 | 295 | acc7 += x3 * c0; |
emilmont | 1:fdd22bb7aa52 | 296 | |
emilmont | 1:fdd22bb7aa52 | 297 | /* Read the b[numTaps-4] coefficient */ |
emilmont | 1:fdd22bb7aa52 | 298 | c0 = *(pb++); |
emilmont | 1:fdd22bb7aa52 | 299 | |
emilmont | 1:fdd22bb7aa52 | 300 | /* Read x[n-numTaps-6] sample */ |
emilmont | 1:fdd22bb7aa52 | 301 | x4 = *(px++); |
emilmont | 1:fdd22bb7aa52 | 302 | |
emilmont | 1:fdd22bb7aa52 | 303 | /* Perform the multiply-accumulates */ |
emilmont | 1:fdd22bb7aa52 | 304 | acc0 += x5 * c0; |
emilmont | 1:fdd22bb7aa52 | 305 | acc1 += x6 * c0; |
emilmont | 1:fdd22bb7aa52 | 306 | acc2 += x7 * c0; |
emilmont | 1:fdd22bb7aa52 | 307 | acc3 += x0 * c0; |
emilmont | 1:fdd22bb7aa52 | 308 | acc4 += x1 * c0; |
emilmont | 1:fdd22bb7aa52 | 309 | acc5 += x2 * c0; |
emilmont | 1:fdd22bb7aa52 | 310 | acc6 += x3 * c0; |
emilmont | 1:fdd22bb7aa52 | 311 | acc7 += x4 * c0; |
emilmont | 1:fdd22bb7aa52 | 312 | |
emilmont | 1:fdd22bb7aa52 | 313 | /* Read the b[numTaps-4] coefficient */ |
emilmont | 1:fdd22bb7aa52 | 314 | c0 = *(pb++); |
emilmont | 1:fdd22bb7aa52 | 315 | |
emilmont | 1:fdd22bb7aa52 | 316 | /* Read x[n-numTaps-6] sample */ |
emilmont | 1:fdd22bb7aa52 | 317 | x5 = *(px++); |
emilmont | 1:fdd22bb7aa52 | 318 | |
emilmont | 1:fdd22bb7aa52 | 319 | /* Perform the multiply-accumulates */ |
emilmont | 1:fdd22bb7aa52 | 320 | acc0 += x6 * c0; |
emilmont | 1:fdd22bb7aa52 | 321 | acc1 += x7 * c0; |
emilmont | 1:fdd22bb7aa52 | 322 | acc2 += x0 * c0; |
emilmont | 1:fdd22bb7aa52 | 323 | acc3 += x1 * c0; |
emilmont | 1:fdd22bb7aa52 | 324 | acc4 += x2 * c0; |
emilmont | 1:fdd22bb7aa52 | 325 | acc5 += x3 * c0; |
emilmont | 1:fdd22bb7aa52 | 326 | acc6 += x4 * c0; |
emilmont | 1:fdd22bb7aa52 | 327 | acc7 += x5 * c0; |
emilmont | 1:fdd22bb7aa52 | 328 | |
emilmont | 1:fdd22bb7aa52 | 329 | /* Read the b[numTaps-4] coefficient */ |
emilmont | 1:fdd22bb7aa52 | 330 | c0 = *(pb++); |
emilmont | 1:fdd22bb7aa52 | 331 | |
emilmont | 1:fdd22bb7aa52 | 332 | /* Read x[n-numTaps-6] sample */ |
emilmont | 1:fdd22bb7aa52 | 333 | x6 = *(px++); |
emilmont | 1:fdd22bb7aa52 | 334 | |
emilmont | 1:fdd22bb7aa52 | 335 | /* Perform the multiply-accumulates */ |
emilmont | 1:fdd22bb7aa52 | 336 | acc0 += x7 * c0; |
emilmont | 1:fdd22bb7aa52 | 337 | acc1 += x0 * c0; |
emilmont | 1:fdd22bb7aa52 | 338 | acc2 += x1 * c0; |
emilmont | 1:fdd22bb7aa52 | 339 | acc3 += x2 * c0; |
emilmont | 1:fdd22bb7aa52 | 340 | acc4 += x3 * c0; |
emilmont | 1:fdd22bb7aa52 | 341 | acc5 += x4 * c0; |
emilmont | 1:fdd22bb7aa52 | 342 | acc6 += x5 * c0; |
emilmont | 1:fdd22bb7aa52 | 343 | acc7 += x6 * c0; |
emilmont | 1:fdd22bb7aa52 | 344 | |
emilmont | 1:fdd22bb7aa52 | 345 | tapCnt--; |
emilmont | 1:fdd22bb7aa52 | 346 | } |
emilmont | 1:fdd22bb7aa52 | 347 | |
emilmont | 1:fdd22bb7aa52 | 348 | /* If the filter length is not a multiple of 4, compute the remaining filter taps */ |
emilmont | 1:fdd22bb7aa52 | 349 | tapCnt = numTaps % 0x8u; |
emilmont | 1:fdd22bb7aa52 | 350 | |
emilmont | 1:fdd22bb7aa52 | 351 | while(tapCnt > 0u) |
emilmont | 1:fdd22bb7aa52 | 352 | { |
emilmont | 1:fdd22bb7aa52 | 353 | /* Read coefficients */ |
emilmont | 1:fdd22bb7aa52 | 354 | c0 = *(pb++); |
emilmont | 1:fdd22bb7aa52 | 355 | |
emilmont | 1:fdd22bb7aa52 | 356 | /* Fetch 1 state variable */ |
emilmont | 1:fdd22bb7aa52 | 357 | x7 = *(px++); |
emilmont | 1:fdd22bb7aa52 | 358 | |
emilmont | 1:fdd22bb7aa52 | 359 | /* Perform the multiply-accumulates */ |
emilmont | 1:fdd22bb7aa52 | 360 | acc0 += x0 * c0; |
emilmont | 1:fdd22bb7aa52 | 361 | acc1 += x1 * c0; |
emilmont | 1:fdd22bb7aa52 | 362 | acc2 += x2 * c0; |
emilmont | 1:fdd22bb7aa52 | 363 | acc3 += x3 * c0; |
emilmont | 1:fdd22bb7aa52 | 364 | acc4 += x4 * c0; |
emilmont | 1:fdd22bb7aa52 | 365 | acc5 += x5 * c0; |
emilmont | 1:fdd22bb7aa52 | 366 | acc6 += x6 * c0; |
emilmont | 1:fdd22bb7aa52 | 367 | acc7 += x7 * c0; |
emilmont | 1:fdd22bb7aa52 | 368 | |
emilmont | 1:fdd22bb7aa52 | 369 | /* Reuse the present sample states for next sample */ |
emilmont | 1:fdd22bb7aa52 | 370 | x0 = x1; |
emilmont | 1:fdd22bb7aa52 | 371 | x1 = x2; |
emilmont | 1:fdd22bb7aa52 | 372 | x2 = x3; |
emilmont | 1:fdd22bb7aa52 | 373 | x3 = x4; |
emilmont | 1:fdd22bb7aa52 | 374 | x4 = x5; |
emilmont | 1:fdd22bb7aa52 | 375 | x5 = x6; |
emilmont | 1:fdd22bb7aa52 | 376 | x6 = x7; |
emilmont | 1:fdd22bb7aa52 | 377 | |
emilmont | 1:fdd22bb7aa52 | 378 | /* Decrement the loop counter */ |
emilmont | 1:fdd22bb7aa52 | 379 | tapCnt--; |
emilmont | 1:fdd22bb7aa52 | 380 | } |
emilmont | 1:fdd22bb7aa52 | 381 | |
emilmont | 1:fdd22bb7aa52 | 382 | /* Advance the state pointer by 4 to process the next group of 4 samples */ |
emilmont | 1:fdd22bb7aa52 | 383 | pState = pState + 8; |
emilmont | 1:fdd22bb7aa52 | 384 | |
emilmont | 1:fdd22bb7aa52 | 385 | /* The results in the 4 accumulators, store in the destination buffer. */ |
emilmont | 1:fdd22bb7aa52 | 386 | *pDst++ = acc0; |
emilmont | 1:fdd22bb7aa52 | 387 | *pDst++ = acc1; |
emilmont | 1:fdd22bb7aa52 | 388 | *pDst++ = acc2; |
emilmont | 1:fdd22bb7aa52 | 389 | *pDst++ = acc3; |
emilmont | 1:fdd22bb7aa52 | 390 | *pDst++ = acc4; |
emilmont | 1:fdd22bb7aa52 | 391 | *pDst++ = acc5; |
emilmont | 1:fdd22bb7aa52 | 392 | *pDst++ = acc6; |
emilmont | 1:fdd22bb7aa52 | 393 | *pDst++ = acc7; |
emilmont | 1:fdd22bb7aa52 | 394 | |
emilmont | 1:fdd22bb7aa52 | 395 | blkCnt--; |
emilmont | 1:fdd22bb7aa52 | 396 | } |
emilmont | 1:fdd22bb7aa52 | 397 | |
emilmont | 1:fdd22bb7aa52 | 398 | /* If the blockSize is not a multiple of 4, compute any remaining output samples here. |
emilmont | 1:fdd22bb7aa52 | 399 | ** No loop unrolling is used. */ |
emilmont | 1:fdd22bb7aa52 | 400 | blkCnt = blockSize % 0x8u; |
emilmont | 1:fdd22bb7aa52 | 401 | |
emilmont | 1:fdd22bb7aa52 | 402 | while(blkCnt > 0u) |
emilmont | 1:fdd22bb7aa52 | 403 | { |
emilmont | 1:fdd22bb7aa52 | 404 | /* Copy one sample at a time into state buffer */ |
emilmont | 1:fdd22bb7aa52 | 405 | *pStateCurnt++ = *pSrc++; |
emilmont | 1:fdd22bb7aa52 | 406 | |
emilmont | 1:fdd22bb7aa52 | 407 | /* Set the accumulator to zero */ |
emilmont | 1:fdd22bb7aa52 | 408 | acc0 = 0.0f; |
emilmont | 1:fdd22bb7aa52 | 409 | |
emilmont | 1:fdd22bb7aa52 | 410 | /* Initialize state pointer */ |
emilmont | 1:fdd22bb7aa52 | 411 | px = pState; |
emilmont | 1:fdd22bb7aa52 | 412 | |
emilmont | 1:fdd22bb7aa52 | 413 | /* Initialize Coefficient pointer */ |
emilmont | 1:fdd22bb7aa52 | 414 | pb = (pCoeffs); |
emilmont | 1:fdd22bb7aa52 | 415 | |
emilmont | 1:fdd22bb7aa52 | 416 | i = numTaps; |
emilmont | 1:fdd22bb7aa52 | 417 | |
emilmont | 1:fdd22bb7aa52 | 418 | /* Perform the multiply-accumulates */ |
emilmont | 1:fdd22bb7aa52 | 419 | do |
emilmont | 1:fdd22bb7aa52 | 420 | { |
emilmont | 1:fdd22bb7aa52 | 421 | acc0 += *px++ * *pb++; |
emilmont | 1:fdd22bb7aa52 | 422 | i--; |
emilmont | 1:fdd22bb7aa52 | 423 | |
emilmont | 1:fdd22bb7aa52 | 424 | } while(i > 0u); |
emilmont | 1:fdd22bb7aa52 | 425 | |
emilmont | 1:fdd22bb7aa52 | 426 | /* The result is store in the destination buffer. */ |
emilmont | 1:fdd22bb7aa52 | 427 | *pDst++ = acc0; |
emilmont | 1:fdd22bb7aa52 | 428 | |
emilmont | 1:fdd22bb7aa52 | 429 | /* Advance state pointer by 1 for the next sample */ |
emilmont | 1:fdd22bb7aa52 | 430 | pState = pState + 1; |
emilmont | 1:fdd22bb7aa52 | 431 | |
emilmont | 1:fdd22bb7aa52 | 432 | blkCnt--; |
emilmont | 1:fdd22bb7aa52 | 433 | } |
emilmont | 1:fdd22bb7aa52 | 434 | |
emilmont | 1:fdd22bb7aa52 | 435 | /* Processing is complete. |
emilmont | 1:fdd22bb7aa52 | 436 | ** Now copy the last numTaps - 1 samples to the satrt of the state buffer. |
emilmont | 1:fdd22bb7aa52 | 437 | ** This prepares the state buffer for the next function call. */ |
emilmont | 1:fdd22bb7aa52 | 438 | |
emilmont | 1:fdd22bb7aa52 | 439 | /* Points to the start of the state buffer */ |
emilmont | 1:fdd22bb7aa52 | 440 | pStateCurnt = S->pState; |
emilmont | 1:fdd22bb7aa52 | 441 | |
emilmont | 1:fdd22bb7aa52 | 442 | tapCnt = (numTaps - 1u) >> 2u; |
emilmont | 1:fdd22bb7aa52 | 443 | |
emilmont | 1:fdd22bb7aa52 | 444 | /* copy data */ |
emilmont | 1:fdd22bb7aa52 | 445 | while(tapCnt > 0u) |
emilmont | 1:fdd22bb7aa52 | 446 | { |
emilmont | 1:fdd22bb7aa52 | 447 | *pStateCurnt++ = *pState++; |
emilmont | 1:fdd22bb7aa52 | 448 | *pStateCurnt++ = *pState++; |
emilmont | 1:fdd22bb7aa52 | 449 | *pStateCurnt++ = *pState++; |
emilmont | 1:fdd22bb7aa52 | 450 | *pStateCurnt++ = *pState++; |
emilmont | 1:fdd22bb7aa52 | 451 | |
emilmont | 1:fdd22bb7aa52 | 452 | /* Decrement the loop counter */ |
emilmont | 1:fdd22bb7aa52 | 453 | tapCnt--; |
emilmont | 1:fdd22bb7aa52 | 454 | } |
emilmont | 1:fdd22bb7aa52 | 455 | |
emilmont | 1:fdd22bb7aa52 | 456 | /* Calculate remaining number of copies */ |
emilmont | 1:fdd22bb7aa52 | 457 | tapCnt = (numTaps - 1u) % 0x4u; |
emilmont | 1:fdd22bb7aa52 | 458 | |
emilmont | 1:fdd22bb7aa52 | 459 | /* Copy the remaining q31_t data */ |
emilmont | 1:fdd22bb7aa52 | 460 | while(tapCnt > 0u) |
emilmont | 1:fdd22bb7aa52 | 461 | { |
emilmont | 1:fdd22bb7aa52 | 462 | *pStateCurnt++ = *pState++; |
emilmont | 1:fdd22bb7aa52 | 463 | |
emilmont | 1:fdd22bb7aa52 | 464 | /* Decrement the loop counter */ |
emilmont | 1:fdd22bb7aa52 | 465 | tapCnt--; |
emilmont | 1:fdd22bb7aa52 | 466 | } |
emilmont | 1:fdd22bb7aa52 | 467 | } |
emilmont | 1:fdd22bb7aa52 | 468 | |
emilmont | 1:fdd22bb7aa52 | 469 | #else |
emilmont | 1:fdd22bb7aa52 | 470 | |
emilmont | 1:fdd22bb7aa52 | 471 | void arm_fir_f32( |
emilmont | 1:fdd22bb7aa52 | 472 | const arm_fir_instance_f32 * S, |
emilmont | 1:fdd22bb7aa52 | 473 | float32_t * pSrc, |
emilmont | 1:fdd22bb7aa52 | 474 | float32_t * pDst, |
emilmont | 1:fdd22bb7aa52 | 475 | uint32_t blockSize) |
emilmont | 1:fdd22bb7aa52 | 476 | { |
emilmont | 1:fdd22bb7aa52 | 477 | float32_t *pState = S->pState; /* State pointer */ |
emilmont | 1:fdd22bb7aa52 | 478 | float32_t *pCoeffs = S->pCoeffs; /* Coefficient pointer */ |
emilmont | 1:fdd22bb7aa52 | 479 | float32_t *pStateCurnt; /* Points to the current sample of the state */ |
emilmont | 1:fdd22bb7aa52 | 480 | float32_t *px, *pb; /* Temporary pointers for state and coefficient buffers */ |
emilmont | 1:fdd22bb7aa52 | 481 | uint32_t numTaps = S->numTaps; /* Number of filter coefficients in the filter */ |
emilmont | 1:fdd22bb7aa52 | 482 | uint32_t i, tapCnt, blkCnt; /* Loop counters */ |
emilmont | 1:fdd22bb7aa52 | 483 | |
emilmont | 1:fdd22bb7aa52 | 484 | /* Run the below code for Cortex-M0 */ |
emilmont | 1:fdd22bb7aa52 | 485 | |
emilmont | 1:fdd22bb7aa52 | 486 | float32_t acc; |
emilmont | 1:fdd22bb7aa52 | 487 | |
emilmont | 1:fdd22bb7aa52 | 488 | /* S->pState points to state array which contains previous frame (numTaps - 1) samples */ |
emilmont | 1:fdd22bb7aa52 | 489 | /* pStateCurnt points to the location where the new input data should be written */ |
emilmont | 1:fdd22bb7aa52 | 490 | pStateCurnt = &(S->pState[(numTaps - 1u)]); |
emilmont | 1:fdd22bb7aa52 | 491 | |
emilmont | 1:fdd22bb7aa52 | 492 | /* Initialize blkCnt with blockSize */ |
emilmont | 1:fdd22bb7aa52 | 493 | blkCnt = blockSize; |
emilmont | 1:fdd22bb7aa52 | 494 | |
emilmont | 1:fdd22bb7aa52 | 495 | while(blkCnt > 0u) |
emilmont | 1:fdd22bb7aa52 | 496 | { |
emilmont | 1:fdd22bb7aa52 | 497 | /* Copy one sample at a time into state buffer */ |
emilmont | 1:fdd22bb7aa52 | 498 | *pStateCurnt++ = *pSrc++; |
emilmont | 1:fdd22bb7aa52 | 499 | |
emilmont | 1:fdd22bb7aa52 | 500 | /* Set the accumulator to zero */ |
emilmont | 1:fdd22bb7aa52 | 501 | acc = 0.0f; |
emilmont | 1:fdd22bb7aa52 | 502 | |
emilmont | 1:fdd22bb7aa52 | 503 | /* Initialize state pointer */ |
emilmont | 1:fdd22bb7aa52 | 504 | px = pState; |
emilmont | 1:fdd22bb7aa52 | 505 | |
emilmont | 1:fdd22bb7aa52 | 506 | /* Initialize Coefficient pointer */ |
emilmont | 1:fdd22bb7aa52 | 507 | pb = pCoeffs; |
emilmont | 1:fdd22bb7aa52 | 508 | |
emilmont | 1:fdd22bb7aa52 | 509 | i = numTaps; |
emilmont | 1:fdd22bb7aa52 | 510 | |
emilmont | 1:fdd22bb7aa52 | 511 | /* Perform the multiply-accumulates */ |
emilmont | 1:fdd22bb7aa52 | 512 | do |
emilmont | 1:fdd22bb7aa52 | 513 | { |
emilmont | 1:fdd22bb7aa52 | 514 | /* 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] */ |
emilmont | 1:fdd22bb7aa52 | 515 | acc += *px++ * *pb++; |
emilmont | 1:fdd22bb7aa52 | 516 | i--; |
emilmont | 1:fdd22bb7aa52 | 517 | |
emilmont | 1:fdd22bb7aa52 | 518 | } while(i > 0u); |
emilmont | 1:fdd22bb7aa52 | 519 | |
emilmont | 1:fdd22bb7aa52 | 520 | /* The result is store in the destination buffer. */ |
emilmont | 1:fdd22bb7aa52 | 521 | *pDst++ = acc; |
emilmont | 1:fdd22bb7aa52 | 522 | |
emilmont | 1:fdd22bb7aa52 | 523 | /* Advance state pointer by 1 for the next sample */ |
emilmont | 1:fdd22bb7aa52 | 524 | pState = pState + 1; |
emilmont | 1:fdd22bb7aa52 | 525 | |
emilmont | 1:fdd22bb7aa52 | 526 | blkCnt--; |
emilmont | 1:fdd22bb7aa52 | 527 | } |
emilmont | 1:fdd22bb7aa52 | 528 | |
emilmont | 1:fdd22bb7aa52 | 529 | /* Processing is complete. |
emilmont | 1:fdd22bb7aa52 | 530 | ** Now copy the last numTaps - 1 samples to the starting of the state buffer. |
emilmont | 1:fdd22bb7aa52 | 531 | ** This prepares the state buffer for the next function call. */ |
emilmont | 1:fdd22bb7aa52 | 532 | |
emilmont | 1:fdd22bb7aa52 | 533 | /* Points to the start of the state buffer */ |
emilmont | 1:fdd22bb7aa52 | 534 | pStateCurnt = S->pState; |
emilmont | 1:fdd22bb7aa52 | 535 | |
emilmont | 1:fdd22bb7aa52 | 536 | /* Copy numTaps number of values */ |
emilmont | 1:fdd22bb7aa52 | 537 | tapCnt = numTaps - 1u; |
emilmont | 1:fdd22bb7aa52 | 538 | |
emilmont | 1:fdd22bb7aa52 | 539 | /* Copy data */ |
emilmont | 1:fdd22bb7aa52 | 540 | while(tapCnt > 0u) |
emilmont | 1:fdd22bb7aa52 | 541 | { |
emilmont | 1:fdd22bb7aa52 | 542 | *pStateCurnt++ = *pState++; |
emilmont | 1:fdd22bb7aa52 | 543 | |
emilmont | 1:fdd22bb7aa52 | 544 | /* Decrement the loop counter */ |
emilmont | 1:fdd22bb7aa52 | 545 | tapCnt--; |
emilmont | 1:fdd22bb7aa52 | 546 | } |
emilmont | 1:fdd22bb7aa52 | 547 | |
emilmont | 1:fdd22bb7aa52 | 548 | } |
emilmont | 1:fdd22bb7aa52 | 549 | |
emilmont | 1:fdd22bb7aa52 | 550 | #endif /* #ifndef ARM_MATH_CM0 */ |
emilmont | 1:fdd22bb7aa52 | 551 | |
emilmont | 1:fdd22bb7aa52 | 552 | /** |
emilmont | 1:fdd22bb7aa52 | 553 | * @} end of FIR group |
emilmont | 1:fdd22bb7aa52 | 554 | */ |