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CMSIS DSP library

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cmsis_dsp/FilteringFunctions/arm_fir_fast_q31.c@2:da51fb522205, 2013-05-30 (annotated)

Committer:
emilmont
Date:
Thu May 30 17:10:11 2013 +0100
Revision:
2:da51fb522205
Parent:
1:fdd22bb7aa52
Child:
3:7a284390b0ce
Keep "cmsis-dsp" module in synch with its source

Who changed what in which revision?

UserRevisionLine numberNew contents of line
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 2:da51fb522205 5 * $Revision: V1.1.0
emilmont 1:fdd22bb7aa52 6 *
emilmont 2:da51fb522205 7 * Project: CMSIS DSP Library
emilmont 2:da51fb522205 8 * Title: arm_fir_fast_q31.c
emilmont 1:fdd22bb7aa52 9 *
emilmont 2:da51fb522205 10 * Description: Processing function for the Q31 Fast FIR filter.
emilmont 1:fdd22bb7aa52 11 *
emilmont 1:fdd22bb7aa52 12 * Target Processor: Cortex-M4/Cortex-M3
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 1.0.10 2011/7/15
emilmont 1:fdd22bb7aa52 18 * Big Endian support added and Merged M0 and M3/M4 Source code.
emilmont 1:fdd22bb7aa52 19 *
emilmont 1:fdd22bb7aa52 20 * Version 1.0.3 2010/11/29
emilmont 1:fdd22bb7aa52 21 * Re-organized the CMSIS folders and updated documentation.
emilmont 1:fdd22bb7aa52 22 *
emilmont 1:fdd22bb7aa52 23 * Version 1.0.2 2010/11/11
emilmont 1:fdd22bb7aa52 24 * Documentation updated.
emilmont 1:fdd22bb7aa52 25 *
emilmont 1:fdd22bb7aa52 26 * Version 1.0.1 2010/10/05
emilmont 1:fdd22bb7aa52 27 * Production release and review comments incorporated.
emilmont 1:fdd22bb7aa52 28 *
emilmont 1:fdd22bb7aa52 29 * Version 1.0.0 2010/09/20
emilmont 1:fdd22bb7aa52 30 * Production release and review comments incorporated.
emilmont 1:fdd22bb7aa52 31 *
emilmont 1:fdd22bb7aa52 32 * Version 0.0.9 2010/08/27
emilmont 1:fdd22bb7aa52 33 * Initial version
emilmont 1:fdd22bb7aa52 34 * -------------------------------------------------------------------- */
emilmont 1:fdd22bb7aa52 35
emilmont 1:fdd22bb7aa52 36 #include "arm_math.h"
emilmont 1:fdd22bb7aa52 37
emilmont 1:fdd22bb7aa52 38 /**
emilmont 1:fdd22bb7aa52 39 * @ingroup groupFilters
emilmont 1:fdd22bb7aa52 40 */
emilmont 1:fdd22bb7aa52 41
emilmont 1:fdd22bb7aa52 42 /**
emilmont 1:fdd22bb7aa52 43 * @addtogroup FIR
emilmont 1:fdd22bb7aa52 44 * @{
emilmont 1:fdd22bb7aa52 45 */
emilmont 1:fdd22bb7aa52 46
emilmont 1:fdd22bb7aa52 47 /**
emilmont 1:fdd22bb7aa52 48 * @param[in] *S points to an instance of the Q31 structure.
emilmont 1:fdd22bb7aa52 49 * @param[in] *pSrc points to the block of input data.
emilmont 1:fdd22bb7aa52 50 * @param[out] *pDst points to the block output data.
emilmont 1:fdd22bb7aa52 51 * @param[in] blockSize number of samples to process per call.
emilmont 1:fdd22bb7aa52 52 * @return none.
emilmont 1:fdd22bb7aa52 53 *
emilmont 1:fdd22bb7aa52 54 * <b>Scaling and Overflow Behavior:</b>
emilmont 1:fdd22bb7aa52 55 *
emilmont 1:fdd22bb7aa52 56 * \par
emilmont 1:fdd22bb7aa52 57 * This function is optimized for speed at the expense of fixed-point precision and overflow protection.
emilmont 1:fdd22bb7aa52 58 * The result of each 1.31 x 1.31 multiplication is truncated to 2.30 format.
emilmont 1:fdd22bb7aa52 59 * These intermediate results are added to a 2.30 accumulator.
emilmont 1:fdd22bb7aa52 60 * Finally, the accumulator is saturated and converted to a 1.31 result.
emilmont 1:fdd22bb7aa52 61 * The fast version has the same overflow behavior as the standard version and provides less precision since it discards the low 32 bits of each multiplication result.
emilmont 1:fdd22bb7aa52 62 * In order to avoid overflows completely the input signal must be scaled down by log2(numTaps) bits.
emilmont 1:fdd22bb7aa52 63 *
emilmont 1:fdd22bb7aa52 64 * \par
emilmont 1:fdd22bb7aa52 65 * Refer to the function <code>arm_fir_q31()</code> for a slower implementation of this function which uses a 64-bit accumulator to provide higher precision. Both the slow and the fast versions use the same instance structure.
emilmont 1:fdd22bb7aa52 66 * Use the function <code>arm_fir_init_q31()</code> to initialize the filter structure.
emilmont 1:fdd22bb7aa52 67 */
emilmont 1:fdd22bb7aa52 68
emilmont 1:fdd22bb7aa52 69 void arm_fir_fast_q31(
emilmont 1:fdd22bb7aa52 70 const arm_fir_instance_q31 * S,
emilmont 1:fdd22bb7aa52 71 q31_t * pSrc,
emilmont 1:fdd22bb7aa52 72 q31_t * pDst,
emilmont 1:fdd22bb7aa52 73 uint32_t blockSize)
emilmont 1:fdd22bb7aa52 74 {
emilmont 1:fdd22bb7aa52 75 q31_t *pState = S->pState; /* State pointer */
emilmont 1:fdd22bb7aa52 76 q31_t *pCoeffs = S->pCoeffs; /* Coefficient pointer */
emilmont 1:fdd22bb7aa52 77 q31_t *pStateCurnt; /* Points to the current sample of the state */
emilmont 1:fdd22bb7aa52 78 q31_t x0, x1, x2, x3; /* Temporary variables to hold state */
emilmont 1:fdd22bb7aa52 79 q31_t c0; /* Temporary variable to hold coefficient value */
emilmont 1:fdd22bb7aa52 80 q31_t *px; /* Temporary pointer for state */
emilmont 1:fdd22bb7aa52 81 q31_t *pb; /* Temporary pointer for coefficient buffer */
emilmont 1:fdd22bb7aa52 82 q31_t acc0, acc1, acc2, acc3; /* Accumulators */
emilmont 1:fdd22bb7aa52 83 uint32_t numTaps = S->numTaps; /* Number of filter coefficients in the filter */
emilmont 1:fdd22bb7aa52 84 uint32_t i, tapCnt, blkCnt; /* Loop counters */
emilmont 1:fdd22bb7aa52 85
emilmont 1:fdd22bb7aa52 86 /* S->pState points to buffer which contains previous frame (numTaps - 1) samples */
emilmont 1:fdd22bb7aa52 87 /* pStateCurnt points to the location where the new input data should be written */
emilmont 1:fdd22bb7aa52 88 pStateCurnt = &(S->pState[(numTaps - 1u)]);
emilmont 1:fdd22bb7aa52 89
emilmont 1:fdd22bb7aa52 90 /* Apply loop unrolling and compute 4 output values simultaneously.
emilmont 1:fdd22bb7aa52 91 * The variables acc0 ... acc3 hold output values that are being computed:
emilmont 1:fdd22bb7aa52 92 *
emilmont 1:fdd22bb7aa52 93 * 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 94 * 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 95 * 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 96 * 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 97 */
emilmont 1:fdd22bb7aa52 98 blkCnt = blockSize >> 2;
emilmont 1:fdd22bb7aa52 99
emilmont 1:fdd22bb7aa52 100 /* First part of the processing with loop unrolling. Compute 4 outputs at a time.
emilmont 1:fdd22bb7aa52 101 ** a second loop below computes the remaining 1 to 3 samples. */
emilmont 1:fdd22bb7aa52 102 while(blkCnt > 0u)
emilmont 1:fdd22bb7aa52 103 {
emilmont 1:fdd22bb7aa52 104 /* Copy four new input samples into the state buffer */
emilmont 1:fdd22bb7aa52 105 *pStateCurnt++ = *pSrc++;
emilmont 1:fdd22bb7aa52 106 *pStateCurnt++ = *pSrc++;
emilmont 1:fdd22bb7aa52 107 *pStateCurnt++ = *pSrc++;
emilmont 1:fdd22bb7aa52 108 *pStateCurnt++ = *pSrc++;
emilmont 1:fdd22bb7aa52 109
emilmont 1:fdd22bb7aa52 110 /* Set all accumulators to zero */
emilmont 1:fdd22bb7aa52 111 acc0 = 0;
emilmont 1:fdd22bb7aa52 112 acc1 = 0;
emilmont 1:fdd22bb7aa52 113 acc2 = 0;
emilmont 1:fdd22bb7aa52 114 acc3 = 0;
emilmont 1:fdd22bb7aa52 115
emilmont 1:fdd22bb7aa52 116 /* Initialize state pointer */
emilmont 1:fdd22bb7aa52 117 px = pState;
emilmont 1:fdd22bb7aa52 118
emilmont 1:fdd22bb7aa52 119 /* Initialize coefficient pointer */
emilmont 1:fdd22bb7aa52 120 pb = pCoeffs;
emilmont 1:fdd22bb7aa52 121
emilmont 1:fdd22bb7aa52 122 /* Read the first three samples from the state buffer:
emilmont 1:fdd22bb7aa52 123 * x[n-numTaps], x[n-numTaps-1], x[n-numTaps-2] */
emilmont 1:fdd22bb7aa52 124 x0 = *(px++);
emilmont 1:fdd22bb7aa52 125 x1 = *(px++);
emilmont 1:fdd22bb7aa52 126 x2 = *(px++);
emilmont 1:fdd22bb7aa52 127
emilmont 1:fdd22bb7aa52 128 /* Loop unrolling. Process 4 taps at a time. */
emilmont 1:fdd22bb7aa52 129 tapCnt = numTaps >> 2;
emilmont 1:fdd22bb7aa52 130 i = tapCnt;
emilmont 1:fdd22bb7aa52 131
emilmont 1:fdd22bb7aa52 132 while(i > 0u)
emilmont 1:fdd22bb7aa52 133 {
emilmont 1:fdd22bb7aa52 134 /* Read the b[numTaps] coefficient */
emilmont 1:fdd22bb7aa52 135 c0 = *(pb++);
emilmont 1:fdd22bb7aa52 136
emilmont 1:fdd22bb7aa52 137 /* Read x[n-numTaps-3] sample */
emilmont 1:fdd22bb7aa52 138 x3 = *(px++);
emilmont 1:fdd22bb7aa52 139
emilmont 1:fdd22bb7aa52 140 /* acc0 += b[numTaps] * x[n-numTaps] */
emilmont 1:fdd22bb7aa52 141 acc0 = (q31_t) ((((q63_t) acc0 << 32) + ((q63_t) x0 * c0)) >> 32);
emilmont 1:fdd22bb7aa52 142
emilmont 1:fdd22bb7aa52 143 /* acc1 += b[numTaps] * x[n-numTaps-1] */
emilmont 1:fdd22bb7aa52 144 acc1 = (q31_t) ((((q63_t) acc1 << 32) + ((q63_t) x1 * c0)) >> 32);
emilmont 1:fdd22bb7aa52 145
emilmont 1:fdd22bb7aa52 146 /* acc2 += b[numTaps] * x[n-numTaps-2] */
emilmont 1:fdd22bb7aa52 147 acc2 = (q31_t) ((((q63_t) acc2 << 32) + ((q63_t) x2 * c0)) >> 32);
emilmont 1:fdd22bb7aa52 148
emilmont 1:fdd22bb7aa52 149 /* acc3 += b[numTaps] * x[n-numTaps-3] */
emilmont 1:fdd22bb7aa52 150 acc3 = (q31_t) ((((q63_t) acc3 << 32) + ((q63_t) x3 * c0)) >> 32);
emilmont 1:fdd22bb7aa52 151
emilmont 1:fdd22bb7aa52 152 /* Read the b[numTaps-1] coefficient */
emilmont 1:fdd22bb7aa52 153 c0 = *(pb++);
emilmont 1:fdd22bb7aa52 154
emilmont 1:fdd22bb7aa52 155 /* Read x[n-numTaps-4] sample */
emilmont 1:fdd22bb7aa52 156 x0 = *(px++);
emilmont 1:fdd22bb7aa52 157
emilmont 1:fdd22bb7aa52 158 /* Perform the multiply-accumulates */
emilmont 1:fdd22bb7aa52 159 acc0 = (q31_t) ((((q63_t) acc0 << 32) + ((q63_t) x1 * c0)) >> 32);
emilmont 1:fdd22bb7aa52 160 acc1 = (q31_t) ((((q63_t) acc1 << 32) + ((q63_t) x2 * c0)) >> 32);
emilmont 1:fdd22bb7aa52 161 acc2 = (q31_t) ((((q63_t) acc2 << 32) + ((q63_t) x3 * c0)) >> 32);
emilmont 1:fdd22bb7aa52 162 acc3 = (q31_t) ((((q63_t) acc3 << 32) + ((q63_t) x0 * c0)) >> 32);
emilmont 1:fdd22bb7aa52 163
emilmont 1:fdd22bb7aa52 164 /* Read the b[numTaps-2] coefficient */
emilmont 1:fdd22bb7aa52 165 c0 = *(pb++);
emilmont 1:fdd22bb7aa52 166
emilmont 1:fdd22bb7aa52 167 /* Read x[n-numTaps-5] sample */
emilmont 1:fdd22bb7aa52 168 x1 = *(px++);
emilmont 1:fdd22bb7aa52 169
emilmont 1:fdd22bb7aa52 170 /* Perform the multiply-accumulates */
emilmont 1:fdd22bb7aa52 171 acc0 = (q31_t) ((((q63_t) acc0 << 32) + ((q63_t) x2 * c0)) >> 32);
emilmont 1:fdd22bb7aa52 172 acc1 = (q31_t) ((((q63_t) acc1 << 32) + ((q63_t) x3 * c0)) >> 32);
emilmont 1:fdd22bb7aa52 173 acc2 = (q31_t) ((((q63_t) acc2 << 32) + ((q63_t) x0 * c0)) >> 32);
emilmont 1:fdd22bb7aa52 174 acc3 = (q31_t) ((((q63_t) acc3 << 32) + ((q63_t) x1 * c0)) >> 32);
emilmont 1:fdd22bb7aa52 175
emilmont 1:fdd22bb7aa52 176 /* Read the b[numTaps-3] coefficients */
emilmont 1:fdd22bb7aa52 177 c0 = *(pb++);
emilmont 1:fdd22bb7aa52 178
emilmont 1:fdd22bb7aa52 179 /* Read x[n-numTaps-6] sample */
emilmont 1:fdd22bb7aa52 180 x2 = *(px++);
emilmont 1:fdd22bb7aa52 181
emilmont 1:fdd22bb7aa52 182 /* Perform the multiply-accumulates */
emilmont 1:fdd22bb7aa52 183 acc0 = (q31_t) ((((q63_t) acc0 << 32) + ((q63_t) x3 * c0)) >> 32);
emilmont 1:fdd22bb7aa52 184 acc1 = (q31_t) ((((q63_t) acc1 << 32) + ((q63_t) x0 * c0)) >> 32);
emilmont 1:fdd22bb7aa52 185 acc2 = (q31_t) ((((q63_t) acc2 << 32) + ((q63_t) x1 * c0)) >> 32);
emilmont 1:fdd22bb7aa52 186 acc3 = (q31_t) ((((q63_t) acc3 << 32) + ((q63_t) x2 * c0)) >> 32);
emilmont 1:fdd22bb7aa52 187 i--;
emilmont 1:fdd22bb7aa52 188 }
emilmont 1:fdd22bb7aa52 189
emilmont 1:fdd22bb7aa52 190 /* If the filter length is not a multiple of 4, compute the remaining filter taps */
emilmont 1:fdd22bb7aa52 191
emilmont 1:fdd22bb7aa52 192 i = numTaps - (tapCnt * 4u);
emilmont 1:fdd22bb7aa52 193 while(i > 0u)
emilmont 1:fdd22bb7aa52 194 {
emilmont 1:fdd22bb7aa52 195 /* Read coefficients */
emilmont 1:fdd22bb7aa52 196 c0 = *(pb++);
emilmont 1:fdd22bb7aa52 197
emilmont 1:fdd22bb7aa52 198 /* Fetch 1 state variable */
emilmont 1:fdd22bb7aa52 199 x3 = *(px++);
emilmont 1:fdd22bb7aa52 200
emilmont 1:fdd22bb7aa52 201 /* Perform the multiply-accumulates */
emilmont 1:fdd22bb7aa52 202 acc0 = (q31_t) ((((q63_t) acc0 << 32) + ((q63_t) x0 * c0)) >> 32);
emilmont 1:fdd22bb7aa52 203 acc1 = (q31_t) ((((q63_t) acc1 << 32) + ((q63_t) x1 * c0)) >> 32);
emilmont 1:fdd22bb7aa52 204 acc2 = (q31_t) ((((q63_t) acc2 << 32) + ((q63_t) x2 * c0)) >> 32);
emilmont 1:fdd22bb7aa52 205 acc3 = (q31_t) ((((q63_t) acc3 << 32) + ((q63_t) x3 * c0)) >> 32);
emilmont 1:fdd22bb7aa52 206
emilmont 1:fdd22bb7aa52 207 /* Reuse the present sample states for next sample */
emilmont 1:fdd22bb7aa52 208 x0 = x1;
emilmont 1:fdd22bb7aa52 209 x1 = x2;
emilmont 1:fdd22bb7aa52 210 x2 = x3;
emilmont 1:fdd22bb7aa52 211
emilmont 1:fdd22bb7aa52 212 /* Decrement the loop counter */
emilmont 1:fdd22bb7aa52 213 i--;
emilmont 1:fdd22bb7aa52 214 }
emilmont 1:fdd22bb7aa52 215
emilmont 1:fdd22bb7aa52 216 /* Advance the state pointer by 4 to process the next group of 4 samples */
emilmont 1:fdd22bb7aa52 217 pState = pState + 4;
emilmont 1:fdd22bb7aa52 218
emilmont 1:fdd22bb7aa52 219 /* The results in the 4 accumulators are in 2.30 format. Convert to 1.31
emilmont 1:fdd22bb7aa52 220 ** Then store the 4 outputs in the destination buffer. */
emilmont 1:fdd22bb7aa52 221 *pDst++ = (q31_t) (acc0 << 1);
emilmont 1:fdd22bb7aa52 222 *pDst++ = (q31_t) (acc1 << 1);
emilmont 1:fdd22bb7aa52 223 *pDst++ = (q31_t) (acc2 << 1);
emilmont 1:fdd22bb7aa52 224 *pDst++ = (q31_t) (acc3 << 1);
emilmont 1:fdd22bb7aa52 225
emilmont 1:fdd22bb7aa52 226 /* Decrement the samples loop counter */
emilmont 1:fdd22bb7aa52 227 blkCnt--;
emilmont 1:fdd22bb7aa52 228 }
emilmont 1:fdd22bb7aa52 229
emilmont 1:fdd22bb7aa52 230
emilmont 1:fdd22bb7aa52 231 /* If the blockSize is not a multiple of 4, compute any remaining output samples here.
emilmont 1:fdd22bb7aa52 232 ** No loop unrolling is used. */
emilmont 1:fdd22bb7aa52 233 blkCnt = blockSize % 4u;
emilmont 1:fdd22bb7aa52 234
emilmont 1:fdd22bb7aa52 235 while(blkCnt > 0u)
emilmont 1:fdd22bb7aa52 236 {
emilmont 1:fdd22bb7aa52 237 /* Copy one sample at a time into state buffer */
emilmont 1:fdd22bb7aa52 238 *pStateCurnt++ = *pSrc++;
emilmont 1:fdd22bb7aa52 239
emilmont 1:fdd22bb7aa52 240 /* Set the accumulator to zero */
emilmont 1:fdd22bb7aa52 241 acc0 = 0;
emilmont 1:fdd22bb7aa52 242
emilmont 1:fdd22bb7aa52 243 /* Initialize state pointer */
emilmont 1:fdd22bb7aa52 244 px = pState;
emilmont 1:fdd22bb7aa52 245
emilmont 1:fdd22bb7aa52 246 /* Initialize Coefficient pointer */
emilmont 1:fdd22bb7aa52 247 pb = (pCoeffs);
emilmont 1:fdd22bb7aa52 248
emilmont 1:fdd22bb7aa52 249 i = numTaps;
emilmont 1:fdd22bb7aa52 250
emilmont 1:fdd22bb7aa52 251 /* Perform the multiply-accumulates */
emilmont 1:fdd22bb7aa52 252 do
emilmont 1:fdd22bb7aa52 253 {
emilmont 1:fdd22bb7aa52 254 acc0 =
emilmont 1:fdd22bb7aa52 255 (q31_t) ((((q63_t) acc0 << 32) +
emilmont 1:fdd22bb7aa52 256 ((q63_t) (*px++) * (*(pb++)))) >> 32);
emilmont 1:fdd22bb7aa52 257 i--;
emilmont 1:fdd22bb7aa52 258 } while(i > 0u);
emilmont 1:fdd22bb7aa52 259
emilmont 1:fdd22bb7aa52 260 /* The result is in 2.30 format. Convert to 1.31
emilmont 1:fdd22bb7aa52 261 ** Then store the output in the destination buffer. */
emilmont 1:fdd22bb7aa52 262 *pDst++ = (q31_t) (acc0 << 1);
emilmont 1:fdd22bb7aa52 263
emilmont 1:fdd22bb7aa52 264 /* Advance state pointer by 1 for the next sample */
emilmont 1:fdd22bb7aa52 265 pState = pState + 1;
emilmont 1:fdd22bb7aa52 266
emilmont 1:fdd22bb7aa52 267 /* Decrement the samples loop counter */
emilmont 1:fdd22bb7aa52 268 blkCnt--;
emilmont 1:fdd22bb7aa52 269 }
emilmont 1:fdd22bb7aa52 270
emilmont 1:fdd22bb7aa52 271 /* Processing is complete.
emilmont 1:fdd22bb7aa52 272 ** Now copy the last numTaps - 1 samples to the satrt of the state buffer.
emilmont 1:fdd22bb7aa52 273 ** This prepares the state buffer for the next function call. */
emilmont 1:fdd22bb7aa52 274
emilmont 1:fdd22bb7aa52 275 /* Points to the start of the state buffer */
emilmont 1:fdd22bb7aa52 276 pStateCurnt = S->pState;
emilmont 1:fdd22bb7aa52 277
emilmont 1:fdd22bb7aa52 278 tapCnt = (numTaps - 1u) >> 2u;
emilmont 1:fdd22bb7aa52 279
emilmont 1:fdd22bb7aa52 280 /* copy data */
emilmont 1:fdd22bb7aa52 281 while(tapCnt > 0u)
emilmont 1:fdd22bb7aa52 282 {
emilmont 1:fdd22bb7aa52 283 *pStateCurnt++ = *pState++;
emilmont 1:fdd22bb7aa52 284 *pStateCurnt++ = *pState++;
emilmont 1:fdd22bb7aa52 285 *pStateCurnt++ = *pState++;
emilmont 1:fdd22bb7aa52 286 *pStateCurnt++ = *pState++;
emilmont 1:fdd22bb7aa52 287
emilmont 1:fdd22bb7aa52 288 /* Decrement the loop counter */
emilmont 1:fdd22bb7aa52 289 tapCnt--;
emilmont 1:fdd22bb7aa52 290 }
emilmont 1:fdd22bb7aa52 291
emilmont 1:fdd22bb7aa52 292 /* Calculate remaining number of copies */
emilmont 1:fdd22bb7aa52 293 tapCnt = (numTaps - 1u) % 0x4u;
emilmont 1:fdd22bb7aa52 294
emilmont 1:fdd22bb7aa52 295 /* Copy the remaining q31_t data */
emilmont 1:fdd22bb7aa52 296 while(tapCnt > 0u)
emilmont 1:fdd22bb7aa52 297 {
emilmont 1:fdd22bb7aa52 298 *pStateCurnt++ = *pState++;
emilmont 1:fdd22bb7aa52 299
emilmont 1:fdd22bb7aa52 300 /* Decrement the loop counter */
emilmont 1:fdd22bb7aa52 301 tapCnt--;
emilmont 1:fdd22bb7aa52 302 }
emilmont 1:fdd22bb7aa52 303
emilmont 1:fdd22bb7aa52 304
emilmont 1:fdd22bb7aa52 305 }
emilmont 1:fdd22bb7aa52 306
emilmont 1:fdd22bb7aa52 307 /**
emilmont 1:fdd22bb7aa52 308 * @} end of FIR group
emilmont 1:fdd22bb7aa52 309 */