CMSIS DSP library
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cmsis_dsp/FilteringFunctions/arm_fir_decimate_q15.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?
User | Revision | Line number | New 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_decimate_q15.c |
emilmont | 1:fdd22bb7aa52 | 9 | * |
emilmont | 2:da51fb522205 | 10 | * Description: Q15 FIR Decimator. |
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 1.0.10 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 0.0.7 2010/06/10 |
emilmont | 1:fdd22bb7aa52 | 33 | * Misra-C changes done |
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_decimate |
emilmont | 1:fdd22bb7aa52 | 44 | * @{ |
emilmont | 1:fdd22bb7aa52 | 45 | */ |
emilmont | 1:fdd22bb7aa52 | 46 | |
emilmont | 1:fdd22bb7aa52 | 47 | /** |
emilmont | 1:fdd22bb7aa52 | 48 | * @brief Processing function for the Q15 FIR decimator. |
emilmont | 1:fdd22bb7aa52 | 49 | * @param[in] *S points to an instance of the Q15 FIR decimator structure. |
emilmont | 1:fdd22bb7aa52 | 50 | * @param[in] *pSrc points to the block of input data. |
emilmont | 1:fdd22bb7aa52 | 51 | * @param[out] *pDst points to the location where the output result is written. |
emilmont | 1:fdd22bb7aa52 | 52 | * @param[in] blockSize number of input samples to process per call. |
emilmont | 1:fdd22bb7aa52 | 53 | * @return none. |
emilmont | 1:fdd22bb7aa52 | 54 | * |
emilmont | 1:fdd22bb7aa52 | 55 | * <b>Scaling and Overflow Behavior:</b> |
emilmont | 1:fdd22bb7aa52 | 56 | * \par |
emilmont | 1:fdd22bb7aa52 | 57 | * The function is implemented using a 64-bit internal accumulator. |
emilmont | 1:fdd22bb7aa52 | 58 | * Both coefficients and state variables are represented in 1.15 format and multiplications yield a 2.30 result. |
emilmont | 1:fdd22bb7aa52 | 59 | * The 2.30 intermediate results are accumulated in a 64-bit accumulator in 34.30 format. |
emilmont | 1:fdd22bb7aa52 | 60 | * There is no risk of internal overflow with this approach and the full precision of intermediate multiplications is preserved. |
emilmont | 1:fdd22bb7aa52 | 61 | * After all additions have been performed, the accumulator is truncated to 34.15 format by discarding low 15 bits. |
emilmont | 1:fdd22bb7aa52 | 62 | * Lastly, the accumulator is saturated to yield a result in 1.15 format. |
emilmont | 1:fdd22bb7aa52 | 63 | * |
emilmont | 1:fdd22bb7aa52 | 64 | * \par |
emilmont | 1:fdd22bb7aa52 | 65 | * Refer to the function <code>arm_fir_decimate_fast_q15()</code> for a faster but less precise implementation of this function for Cortex-M3 and Cortex-M4. |
emilmont | 1:fdd22bb7aa52 | 66 | */ |
emilmont | 1:fdd22bb7aa52 | 67 | |
emilmont | 1:fdd22bb7aa52 | 68 | #ifndef ARM_MATH_CM0 |
emilmont | 1:fdd22bb7aa52 | 69 | |
emilmont | 1:fdd22bb7aa52 | 70 | #ifndef UNALIGNED_SUPPORT_DISABLE |
emilmont | 1:fdd22bb7aa52 | 71 | |
emilmont | 1:fdd22bb7aa52 | 72 | void arm_fir_decimate_q15( |
emilmont | 1:fdd22bb7aa52 | 73 | const arm_fir_decimate_instance_q15 * S, |
emilmont | 1:fdd22bb7aa52 | 74 | q15_t * pSrc, |
emilmont | 1:fdd22bb7aa52 | 75 | q15_t * pDst, |
emilmont | 1:fdd22bb7aa52 | 76 | uint32_t blockSize) |
emilmont | 1:fdd22bb7aa52 | 77 | { |
emilmont | 1:fdd22bb7aa52 | 78 | q15_t *pState = S->pState; /* State pointer */ |
emilmont | 1:fdd22bb7aa52 | 79 | q15_t *pCoeffs = S->pCoeffs; /* Coefficient pointer */ |
emilmont | 1:fdd22bb7aa52 | 80 | q15_t *pStateCurnt; /* Points to the current sample of the state */ |
emilmont | 1:fdd22bb7aa52 | 81 | q15_t *px; /* Temporary pointer for state buffer */ |
emilmont | 1:fdd22bb7aa52 | 82 | q15_t *pb; /* Temporary pointer coefficient buffer */ |
emilmont | 1:fdd22bb7aa52 | 83 | q31_t x0, x1, c0, c1; /* Temporary variables to hold state and coefficient values */ |
emilmont | 1:fdd22bb7aa52 | 84 | q63_t sum0; /* Accumulators */ |
emilmont | 1:fdd22bb7aa52 | 85 | q63_t acc0, acc1; |
emilmont | 1:fdd22bb7aa52 | 86 | q15_t *px0, *px1; |
emilmont | 1:fdd22bb7aa52 | 87 | uint32_t blkCntN3; |
emilmont | 1:fdd22bb7aa52 | 88 | uint32_t numTaps = S->numTaps; /* Number of taps */ |
emilmont | 1:fdd22bb7aa52 | 89 | uint32_t i, blkCnt, tapCnt, outBlockSize = blockSize / S->M; /* Loop counters */ |
emilmont | 1:fdd22bb7aa52 | 90 | |
emilmont | 1:fdd22bb7aa52 | 91 | |
emilmont | 1:fdd22bb7aa52 | 92 | /* S->pState buffer contains previous frame (numTaps - 1) samples */ |
emilmont | 1:fdd22bb7aa52 | 93 | /* pStateCurnt points to the location where the new input data should be written */ |
emilmont | 1:fdd22bb7aa52 | 94 | pStateCurnt = S->pState + (numTaps - 1u); |
emilmont | 1:fdd22bb7aa52 | 95 | |
emilmont | 1:fdd22bb7aa52 | 96 | |
emilmont | 1:fdd22bb7aa52 | 97 | /* Total number of output samples to be computed */ |
emilmont | 1:fdd22bb7aa52 | 98 | blkCnt = outBlockSize / 2; |
emilmont | 1:fdd22bb7aa52 | 99 | blkCntN3 = outBlockSize - (2 * blkCnt); |
emilmont | 1:fdd22bb7aa52 | 100 | |
emilmont | 1:fdd22bb7aa52 | 101 | |
emilmont | 1:fdd22bb7aa52 | 102 | while(blkCnt > 0u) |
emilmont | 1:fdd22bb7aa52 | 103 | { |
emilmont | 1:fdd22bb7aa52 | 104 | /* Copy decimation factor number of new input samples into the state buffer */ |
emilmont | 1:fdd22bb7aa52 | 105 | i = 2 * S->M; |
emilmont | 1:fdd22bb7aa52 | 106 | |
emilmont | 1:fdd22bb7aa52 | 107 | do |
emilmont | 1:fdd22bb7aa52 | 108 | { |
emilmont | 1:fdd22bb7aa52 | 109 | *pStateCurnt++ = *pSrc++; |
emilmont | 1:fdd22bb7aa52 | 110 | |
emilmont | 1:fdd22bb7aa52 | 111 | } while(--i); |
emilmont | 1:fdd22bb7aa52 | 112 | |
emilmont | 1:fdd22bb7aa52 | 113 | /* Set accumulator to zero */ |
emilmont | 1:fdd22bb7aa52 | 114 | acc0 = 0; |
emilmont | 1:fdd22bb7aa52 | 115 | acc1 = 0; |
emilmont | 1:fdd22bb7aa52 | 116 | |
emilmont | 1:fdd22bb7aa52 | 117 | /* Initialize state pointer */ |
emilmont | 1:fdd22bb7aa52 | 118 | px0 = pState; |
emilmont | 1:fdd22bb7aa52 | 119 | |
emilmont | 1:fdd22bb7aa52 | 120 | px1 = pState + S->M; |
emilmont | 1:fdd22bb7aa52 | 121 | |
emilmont | 1:fdd22bb7aa52 | 122 | |
emilmont | 1:fdd22bb7aa52 | 123 | /* Initialize coeff pointer */ |
emilmont | 1:fdd22bb7aa52 | 124 | pb = pCoeffs; |
emilmont | 1:fdd22bb7aa52 | 125 | |
emilmont | 1:fdd22bb7aa52 | 126 | /* Loop unrolling. Process 4 taps at a time. */ |
emilmont | 1:fdd22bb7aa52 | 127 | tapCnt = numTaps >> 2; |
emilmont | 1:fdd22bb7aa52 | 128 | |
emilmont | 1:fdd22bb7aa52 | 129 | /* Loop over the number of taps. Unroll by a factor of 4. |
emilmont | 1:fdd22bb7aa52 | 130 | ** Repeat until we've computed numTaps-4 coefficients. */ |
emilmont | 1:fdd22bb7aa52 | 131 | while(tapCnt > 0u) |
emilmont | 1:fdd22bb7aa52 | 132 | { |
emilmont | 1:fdd22bb7aa52 | 133 | /* Read the Read b[numTaps-1] and b[numTaps-2] coefficients */ |
emilmont | 1:fdd22bb7aa52 | 134 | c0 = *__SIMD32(pb)++; |
emilmont | 1:fdd22bb7aa52 | 135 | |
emilmont | 1:fdd22bb7aa52 | 136 | /* Read x[n-numTaps-1] and x[n-numTaps-2]sample */ |
emilmont | 1:fdd22bb7aa52 | 137 | x0 = *__SIMD32(px0)++; |
emilmont | 1:fdd22bb7aa52 | 138 | |
emilmont | 1:fdd22bb7aa52 | 139 | x1 = *__SIMD32(px1)++; |
emilmont | 1:fdd22bb7aa52 | 140 | |
emilmont | 1:fdd22bb7aa52 | 141 | /* Perform the multiply-accumulate */ |
emilmont | 1:fdd22bb7aa52 | 142 | acc0 = __SMLALD(x0, c0, acc0); |
emilmont | 1:fdd22bb7aa52 | 143 | |
emilmont | 1:fdd22bb7aa52 | 144 | acc1 = __SMLALD(x1, c0, acc1); |
emilmont | 1:fdd22bb7aa52 | 145 | |
emilmont | 1:fdd22bb7aa52 | 146 | /* Read the b[numTaps-3] and b[numTaps-4] coefficient */ |
emilmont | 1:fdd22bb7aa52 | 147 | c0 = *__SIMD32(pb)++; |
emilmont | 1:fdd22bb7aa52 | 148 | |
emilmont | 1:fdd22bb7aa52 | 149 | /* Read x[n-numTaps-2] and x[n-numTaps-3] sample */ |
emilmont | 1:fdd22bb7aa52 | 150 | x0 = *__SIMD32(px0)++; |
emilmont | 1:fdd22bb7aa52 | 151 | |
emilmont | 1:fdd22bb7aa52 | 152 | x1 = *__SIMD32(px1)++; |
emilmont | 1:fdd22bb7aa52 | 153 | |
emilmont | 1:fdd22bb7aa52 | 154 | /* Perform the multiply-accumulate */ |
emilmont | 1:fdd22bb7aa52 | 155 | acc0 = __SMLALD(x0, c0, acc0); |
emilmont | 1:fdd22bb7aa52 | 156 | |
emilmont | 1:fdd22bb7aa52 | 157 | acc1 = __SMLALD(x1, c0, acc1); |
emilmont | 1:fdd22bb7aa52 | 158 | |
emilmont | 1:fdd22bb7aa52 | 159 | /* Decrement the loop counter */ |
emilmont | 1:fdd22bb7aa52 | 160 | tapCnt--; |
emilmont | 1:fdd22bb7aa52 | 161 | } |
emilmont | 1:fdd22bb7aa52 | 162 | |
emilmont | 1:fdd22bb7aa52 | 163 | /* If the filter length is not a multiple of 4, compute the remaining filter taps */ |
emilmont | 1:fdd22bb7aa52 | 164 | tapCnt = numTaps % 0x4u; |
emilmont | 1:fdd22bb7aa52 | 165 | |
emilmont | 1:fdd22bb7aa52 | 166 | while(tapCnt > 0u) |
emilmont | 1:fdd22bb7aa52 | 167 | { |
emilmont | 1:fdd22bb7aa52 | 168 | /* Read coefficients */ |
emilmont | 1:fdd22bb7aa52 | 169 | c0 = *pb++; |
emilmont | 1:fdd22bb7aa52 | 170 | |
emilmont | 1:fdd22bb7aa52 | 171 | /* Fetch 1 state variable */ |
emilmont | 1:fdd22bb7aa52 | 172 | x0 = *px0++; |
emilmont | 1:fdd22bb7aa52 | 173 | |
emilmont | 1:fdd22bb7aa52 | 174 | x1 = *px1++; |
emilmont | 1:fdd22bb7aa52 | 175 | |
emilmont | 1:fdd22bb7aa52 | 176 | /* Perform the multiply-accumulate */ |
emilmont | 1:fdd22bb7aa52 | 177 | acc0 = __SMLALD(x0, c0, acc0); |
emilmont | 1:fdd22bb7aa52 | 178 | acc1 = __SMLALD(x1, c0, acc1); |
emilmont | 1:fdd22bb7aa52 | 179 | |
emilmont | 1:fdd22bb7aa52 | 180 | /* Decrement the loop counter */ |
emilmont | 1:fdd22bb7aa52 | 181 | tapCnt--; |
emilmont | 1:fdd22bb7aa52 | 182 | } |
emilmont | 1:fdd22bb7aa52 | 183 | |
emilmont | 1:fdd22bb7aa52 | 184 | /* Advance the state pointer by the decimation factor |
emilmont | 1:fdd22bb7aa52 | 185 | * to process the next group of decimation factor number samples */ |
emilmont | 1:fdd22bb7aa52 | 186 | pState = pState + S->M * 2; |
emilmont | 1:fdd22bb7aa52 | 187 | |
emilmont | 1:fdd22bb7aa52 | 188 | /* Store filter output, smlad returns the values in 2.14 format */ |
emilmont | 1:fdd22bb7aa52 | 189 | /* so downsacle by 15 to get output in 1.15 */ |
emilmont | 1:fdd22bb7aa52 | 190 | *pDst++ = (q15_t) (__SSAT((acc0 >> 15), 16)); |
emilmont | 1:fdd22bb7aa52 | 191 | *pDst++ = (q15_t) (__SSAT((acc1 >> 15), 16)); |
emilmont | 1:fdd22bb7aa52 | 192 | |
emilmont | 1:fdd22bb7aa52 | 193 | /* Decrement the loop counter */ |
emilmont | 1:fdd22bb7aa52 | 194 | blkCnt--; |
emilmont | 1:fdd22bb7aa52 | 195 | } |
emilmont | 1:fdd22bb7aa52 | 196 | |
emilmont | 1:fdd22bb7aa52 | 197 | |
emilmont | 1:fdd22bb7aa52 | 198 | |
emilmont | 1:fdd22bb7aa52 | 199 | while(blkCntN3 > 0u) |
emilmont | 1:fdd22bb7aa52 | 200 | { |
emilmont | 1:fdd22bb7aa52 | 201 | /* Copy decimation factor number of new input samples into the state buffer */ |
emilmont | 1:fdd22bb7aa52 | 202 | i = S->M; |
emilmont | 1:fdd22bb7aa52 | 203 | |
emilmont | 1:fdd22bb7aa52 | 204 | do |
emilmont | 1:fdd22bb7aa52 | 205 | { |
emilmont | 1:fdd22bb7aa52 | 206 | *pStateCurnt++ = *pSrc++; |
emilmont | 1:fdd22bb7aa52 | 207 | |
emilmont | 1:fdd22bb7aa52 | 208 | } while(--i); |
emilmont | 1:fdd22bb7aa52 | 209 | |
emilmont | 1:fdd22bb7aa52 | 210 | /*Set sum to zero */ |
emilmont | 1:fdd22bb7aa52 | 211 | sum0 = 0; |
emilmont | 1:fdd22bb7aa52 | 212 | |
emilmont | 1:fdd22bb7aa52 | 213 | /* Initialize state pointer */ |
emilmont | 1:fdd22bb7aa52 | 214 | px = pState; |
emilmont | 1:fdd22bb7aa52 | 215 | |
emilmont | 1:fdd22bb7aa52 | 216 | /* Initialize coeff pointer */ |
emilmont | 1:fdd22bb7aa52 | 217 | pb = pCoeffs; |
emilmont | 1:fdd22bb7aa52 | 218 | |
emilmont | 1:fdd22bb7aa52 | 219 | /* Loop unrolling. Process 4 taps at a time. */ |
emilmont | 1:fdd22bb7aa52 | 220 | tapCnt = numTaps >> 2; |
emilmont | 1:fdd22bb7aa52 | 221 | |
emilmont | 1:fdd22bb7aa52 | 222 | /* Loop over the number of taps. Unroll by a factor of 4. |
emilmont | 1:fdd22bb7aa52 | 223 | ** Repeat until we've computed numTaps-4 coefficients. */ |
emilmont | 1:fdd22bb7aa52 | 224 | while(tapCnt > 0u) |
emilmont | 1:fdd22bb7aa52 | 225 | { |
emilmont | 1:fdd22bb7aa52 | 226 | /* Read the Read b[numTaps-1] and b[numTaps-2] coefficients */ |
emilmont | 1:fdd22bb7aa52 | 227 | c0 = *__SIMD32(pb)++; |
emilmont | 1:fdd22bb7aa52 | 228 | |
emilmont | 1:fdd22bb7aa52 | 229 | /* Read x[n-numTaps-1] and x[n-numTaps-2]sample */ |
emilmont | 1:fdd22bb7aa52 | 230 | x0 = *__SIMD32(px)++; |
emilmont | 1:fdd22bb7aa52 | 231 | |
emilmont | 1:fdd22bb7aa52 | 232 | /* Read the b[numTaps-3] and b[numTaps-4] coefficient */ |
emilmont | 1:fdd22bb7aa52 | 233 | c1 = *__SIMD32(pb)++; |
emilmont | 1:fdd22bb7aa52 | 234 | |
emilmont | 1:fdd22bb7aa52 | 235 | /* Perform the multiply-accumulate */ |
emilmont | 1:fdd22bb7aa52 | 236 | sum0 = __SMLALD(x0, c0, sum0); |
emilmont | 1:fdd22bb7aa52 | 237 | |
emilmont | 1:fdd22bb7aa52 | 238 | /* Read x[n-numTaps-2] and x[n-numTaps-3] sample */ |
emilmont | 1:fdd22bb7aa52 | 239 | x0 = *__SIMD32(px)++; |
emilmont | 1:fdd22bb7aa52 | 240 | |
emilmont | 1:fdd22bb7aa52 | 241 | /* Perform the multiply-accumulate */ |
emilmont | 1:fdd22bb7aa52 | 242 | sum0 = __SMLALD(x0, c1, sum0); |
emilmont | 1:fdd22bb7aa52 | 243 | |
emilmont | 1:fdd22bb7aa52 | 244 | /* Decrement the loop counter */ |
emilmont | 1:fdd22bb7aa52 | 245 | tapCnt--; |
emilmont | 1:fdd22bb7aa52 | 246 | } |
emilmont | 1:fdd22bb7aa52 | 247 | |
emilmont | 1:fdd22bb7aa52 | 248 | /* If the filter length is not a multiple of 4, compute the remaining filter taps */ |
emilmont | 1:fdd22bb7aa52 | 249 | tapCnt = numTaps % 0x4u; |
emilmont | 1:fdd22bb7aa52 | 250 | |
emilmont | 1:fdd22bb7aa52 | 251 | while(tapCnt > 0u) |
emilmont | 1:fdd22bb7aa52 | 252 | { |
emilmont | 1:fdd22bb7aa52 | 253 | /* Read coefficients */ |
emilmont | 1:fdd22bb7aa52 | 254 | c0 = *pb++; |
emilmont | 1:fdd22bb7aa52 | 255 | |
emilmont | 1:fdd22bb7aa52 | 256 | /* Fetch 1 state variable */ |
emilmont | 1:fdd22bb7aa52 | 257 | x0 = *px++; |
emilmont | 1:fdd22bb7aa52 | 258 | |
emilmont | 1:fdd22bb7aa52 | 259 | /* Perform the multiply-accumulate */ |
emilmont | 1:fdd22bb7aa52 | 260 | sum0 = __SMLALD(x0, c0, sum0); |
emilmont | 1:fdd22bb7aa52 | 261 | |
emilmont | 1:fdd22bb7aa52 | 262 | /* Decrement the loop counter */ |
emilmont | 1:fdd22bb7aa52 | 263 | tapCnt--; |
emilmont | 1:fdd22bb7aa52 | 264 | } |
emilmont | 1:fdd22bb7aa52 | 265 | |
emilmont | 1:fdd22bb7aa52 | 266 | /* Advance the state pointer by the decimation factor |
emilmont | 1:fdd22bb7aa52 | 267 | * to process the next group of decimation factor number samples */ |
emilmont | 1:fdd22bb7aa52 | 268 | pState = pState + S->M; |
emilmont | 1:fdd22bb7aa52 | 269 | |
emilmont | 1:fdd22bb7aa52 | 270 | /* Store filter output, smlad returns the values in 2.14 format */ |
emilmont | 1:fdd22bb7aa52 | 271 | /* so downsacle by 15 to get output in 1.15 */ |
emilmont | 1:fdd22bb7aa52 | 272 | *pDst++ = (q15_t) (__SSAT((sum0 >> 15), 16)); |
emilmont | 1:fdd22bb7aa52 | 273 | |
emilmont | 1:fdd22bb7aa52 | 274 | /* Decrement the loop counter */ |
emilmont | 1:fdd22bb7aa52 | 275 | blkCntN3--; |
emilmont | 1:fdd22bb7aa52 | 276 | } |
emilmont | 1:fdd22bb7aa52 | 277 | |
emilmont | 1:fdd22bb7aa52 | 278 | /* Processing is complete. |
emilmont | 1:fdd22bb7aa52 | 279 | ** Now copy the last numTaps - 1 samples to the satrt of the state buffer. |
emilmont | 1:fdd22bb7aa52 | 280 | ** This prepares the state buffer for the next function call. */ |
emilmont | 1:fdd22bb7aa52 | 281 | |
emilmont | 1:fdd22bb7aa52 | 282 | /* Points to the start of the state buffer */ |
emilmont | 1:fdd22bb7aa52 | 283 | pStateCurnt = S->pState; |
emilmont | 1:fdd22bb7aa52 | 284 | |
emilmont | 1:fdd22bb7aa52 | 285 | i = (numTaps - 1u) >> 2u; |
emilmont | 1:fdd22bb7aa52 | 286 | |
emilmont | 1:fdd22bb7aa52 | 287 | /* copy data */ |
emilmont | 1:fdd22bb7aa52 | 288 | while(i > 0u) |
emilmont | 1:fdd22bb7aa52 | 289 | { |
emilmont | 1:fdd22bb7aa52 | 290 | *__SIMD32(pStateCurnt)++ = *__SIMD32(pState)++; |
emilmont | 1:fdd22bb7aa52 | 291 | *__SIMD32(pStateCurnt)++ = *__SIMD32(pState)++; |
emilmont | 1:fdd22bb7aa52 | 292 | |
emilmont | 1:fdd22bb7aa52 | 293 | /* Decrement the loop counter */ |
emilmont | 1:fdd22bb7aa52 | 294 | i--; |
emilmont | 1:fdd22bb7aa52 | 295 | } |
emilmont | 1:fdd22bb7aa52 | 296 | |
emilmont | 1:fdd22bb7aa52 | 297 | i = (numTaps - 1u) % 0x04u; |
emilmont | 1:fdd22bb7aa52 | 298 | |
emilmont | 1:fdd22bb7aa52 | 299 | /* copy data */ |
emilmont | 1:fdd22bb7aa52 | 300 | while(i > 0u) |
emilmont | 1:fdd22bb7aa52 | 301 | { |
emilmont | 1:fdd22bb7aa52 | 302 | *pStateCurnt++ = *pState++; |
emilmont | 1:fdd22bb7aa52 | 303 | |
emilmont | 1:fdd22bb7aa52 | 304 | /* Decrement the loop counter */ |
emilmont | 1:fdd22bb7aa52 | 305 | i--; |
emilmont | 1:fdd22bb7aa52 | 306 | } |
emilmont | 1:fdd22bb7aa52 | 307 | } |
emilmont | 1:fdd22bb7aa52 | 308 | |
emilmont | 1:fdd22bb7aa52 | 309 | #else |
emilmont | 1:fdd22bb7aa52 | 310 | |
emilmont | 1:fdd22bb7aa52 | 311 | |
emilmont | 1:fdd22bb7aa52 | 312 | void arm_fir_decimate_q15( |
emilmont | 1:fdd22bb7aa52 | 313 | const arm_fir_decimate_instance_q15 * S, |
emilmont | 1:fdd22bb7aa52 | 314 | q15_t * pSrc, |
emilmont | 1:fdd22bb7aa52 | 315 | q15_t * pDst, |
emilmont | 1:fdd22bb7aa52 | 316 | uint32_t blockSize) |
emilmont | 1:fdd22bb7aa52 | 317 | { |
emilmont | 1:fdd22bb7aa52 | 318 | q15_t *pState = S->pState; /* State pointer */ |
emilmont | 1:fdd22bb7aa52 | 319 | q15_t *pCoeffs = S->pCoeffs; /* Coefficient pointer */ |
emilmont | 1:fdd22bb7aa52 | 320 | q15_t *pStateCurnt; /* Points to the current sample of the state */ |
emilmont | 1:fdd22bb7aa52 | 321 | q15_t *px; /* Temporary pointer for state buffer */ |
emilmont | 1:fdd22bb7aa52 | 322 | q15_t *pb; /* Temporary pointer coefficient buffer */ |
emilmont | 1:fdd22bb7aa52 | 323 | q15_t x0, x1, c0; /* Temporary variables to hold state and coefficient values */ |
emilmont | 1:fdd22bb7aa52 | 324 | q63_t sum0; /* Accumulators */ |
emilmont | 1:fdd22bb7aa52 | 325 | q63_t acc0, acc1; |
emilmont | 1:fdd22bb7aa52 | 326 | q15_t *px0, *px1; |
emilmont | 1:fdd22bb7aa52 | 327 | uint32_t blkCntN3; |
emilmont | 1:fdd22bb7aa52 | 328 | uint32_t numTaps = S->numTaps; /* Number of taps */ |
emilmont | 1:fdd22bb7aa52 | 329 | uint32_t i, blkCnt, tapCnt, outBlockSize = blockSize / S->M; /* Loop counters */ |
emilmont | 1:fdd22bb7aa52 | 330 | |
emilmont | 1:fdd22bb7aa52 | 331 | |
emilmont | 1:fdd22bb7aa52 | 332 | /* S->pState buffer contains previous frame (numTaps - 1) samples */ |
emilmont | 1:fdd22bb7aa52 | 333 | /* pStateCurnt points to the location where the new input data should be written */ |
emilmont | 1:fdd22bb7aa52 | 334 | pStateCurnt = S->pState + (numTaps - 1u); |
emilmont | 1:fdd22bb7aa52 | 335 | |
emilmont | 1:fdd22bb7aa52 | 336 | |
emilmont | 1:fdd22bb7aa52 | 337 | /* Total number of output samples to be computed */ |
emilmont | 1:fdd22bb7aa52 | 338 | blkCnt = outBlockSize / 2; |
emilmont | 1:fdd22bb7aa52 | 339 | blkCntN3 = outBlockSize - (2 * blkCnt); |
emilmont | 1:fdd22bb7aa52 | 340 | |
emilmont | 1:fdd22bb7aa52 | 341 | while(blkCnt > 0u) |
emilmont | 1:fdd22bb7aa52 | 342 | { |
emilmont | 1:fdd22bb7aa52 | 343 | /* Copy decimation factor number of new input samples into the state buffer */ |
emilmont | 1:fdd22bb7aa52 | 344 | i = 2 * S->M; |
emilmont | 1:fdd22bb7aa52 | 345 | |
emilmont | 1:fdd22bb7aa52 | 346 | do |
emilmont | 1:fdd22bb7aa52 | 347 | { |
emilmont | 1:fdd22bb7aa52 | 348 | *pStateCurnt++ = *pSrc++; |
emilmont | 1:fdd22bb7aa52 | 349 | |
emilmont | 1:fdd22bb7aa52 | 350 | } while(--i); |
emilmont | 1:fdd22bb7aa52 | 351 | |
emilmont | 1:fdd22bb7aa52 | 352 | /* Set accumulator to zero */ |
emilmont | 1:fdd22bb7aa52 | 353 | acc0 = 0; |
emilmont | 1:fdd22bb7aa52 | 354 | acc1 = 0; |
emilmont | 1:fdd22bb7aa52 | 355 | |
emilmont | 1:fdd22bb7aa52 | 356 | /* Initialize state pointer */ |
emilmont | 1:fdd22bb7aa52 | 357 | px0 = pState; |
emilmont | 1:fdd22bb7aa52 | 358 | |
emilmont | 1:fdd22bb7aa52 | 359 | px1 = pState + S->M; |
emilmont | 1:fdd22bb7aa52 | 360 | |
emilmont | 1:fdd22bb7aa52 | 361 | |
emilmont | 1:fdd22bb7aa52 | 362 | /* Initialize coeff pointer */ |
emilmont | 1:fdd22bb7aa52 | 363 | pb = pCoeffs; |
emilmont | 1:fdd22bb7aa52 | 364 | |
emilmont | 1:fdd22bb7aa52 | 365 | /* Loop unrolling. Process 4 taps at a time. */ |
emilmont | 1:fdd22bb7aa52 | 366 | tapCnt = numTaps >> 2; |
emilmont | 1:fdd22bb7aa52 | 367 | |
emilmont | 1:fdd22bb7aa52 | 368 | /* Loop over the number of taps. Unroll by a factor of 4. |
emilmont | 1:fdd22bb7aa52 | 369 | ** Repeat until we've computed numTaps-4 coefficients. */ |
emilmont | 1:fdd22bb7aa52 | 370 | while(tapCnt > 0u) |
emilmont | 1:fdd22bb7aa52 | 371 | { |
emilmont | 1:fdd22bb7aa52 | 372 | /* Read the Read b[numTaps-1] coefficients */ |
emilmont | 1:fdd22bb7aa52 | 373 | c0 = *pb++; |
emilmont | 1:fdd22bb7aa52 | 374 | |
emilmont | 1:fdd22bb7aa52 | 375 | /* Read x[n-numTaps-1] for sample 0 and for sample 1 */ |
emilmont | 1:fdd22bb7aa52 | 376 | x0 = *px0++; |
emilmont | 1:fdd22bb7aa52 | 377 | x1 = *px1++; |
emilmont | 1:fdd22bb7aa52 | 378 | |
emilmont | 1:fdd22bb7aa52 | 379 | /* Perform the multiply-accumulate */ |
emilmont | 1:fdd22bb7aa52 | 380 | acc0 += x0 * c0; |
emilmont | 1:fdd22bb7aa52 | 381 | acc1 += x1 * c0; |
emilmont | 1:fdd22bb7aa52 | 382 | |
emilmont | 1:fdd22bb7aa52 | 383 | /* Read the b[numTaps-2] coefficient */ |
emilmont | 1:fdd22bb7aa52 | 384 | c0 = *pb++; |
emilmont | 1:fdd22bb7aa52 | 385 | |
emilmont | 1:fdd22bb7aa52 | 386 | /* Read x[n-numTaps-2] for sample 0 and sample 1 */ |
emilmont | 1:fdd22bb7aa52 | 387 | x0 = *px0++; |
emilmont | 1:fdd22bb7aa52 | 388 | x1 = *px1++; |
emilmont | 1:fdd22bb7aa52 | 389 | |
emilmont | 1:fdd22bb7aa52 | 390 | /* Perform the multiply-accumulate */ |
emilmont | 1:fdd22bb7aa52 | 391 | acc0 += x0 * c0; |
emilmont | 1:fdd22bb7aa52 | 392 | acc1 += x1 * c0; |
emilmont | 1:fdd22bb7aa52 | 393 | |
emilmont | 1:fdd22bb7aa52 | 394 | /* Read the b[numTaps-3] coefficients */ |
emilmont | 1:fdd22bb7aa52 | 395 | c0 = *pb++; |
emilmont | 1:fdd22bb7aa52 | 396 | |
emilmont | 1:fdd22bb7aa52 | 397 | /* Read x[n-numTaps-3] for sample 0 and sample 1 */ |
emilmont | 1:fdd22bb7aa52 | 398 | x0 = *px0++; |
emilmont | 1:fdd22bb7aa52 | 399 | x1 = *px1++; |
emilmont | 1:fdd22bb7aa52 | 400 | |
emilmont | 1:fdd22bb7aa52 | 401 | /* Perform the multiply-accumulate */ |
emilmont | 1:fdd22bb7aa52 | 402 | acc0 += x0 * c0; |
emilmont | 1:fdd22bb7aa52 | 403 | acc1 += x1 * c0; |
emilmont | 1:fdd22bb7aa52 | 404 | |
emilmont | 1:fdd22bb7aa52 | 405 | /* Read the b[numTaps-4] coefficient */ |
emilmont | 1:fdd22bb7aa52 | 406 | c0 = *pb++; |
emilmont | 1:fdd22bb7aa52 | 407 | |
emilmont | 1:fdd22bb7aa52 | 408 | /* Read x[n-numTaps-4] for sample 0 and sample 1 */ |
emilmont | 1:fdd22bb7aa52 | 409 | x0 = *px0++; |
emilmont | 1:fdd22bb7aa52 | 410 | x1 = *px1++; |
emilmont | 1:fdd22bb7aa52 | 411 | |
emilmont | 1:fdd22bb7aa52 | 412 | /* Perform the multiply-accumulate */ |
emilmont | 1:fdd22bb7aa52 | 413 | acc0 += x0 * c0; |
emilmont | 1:fdd22bb7aa52 | 414 | acc1 += x1 * c0; |
emilmont | 1:fdd22bb7aa52 | 415 | |
emilmont | 1:fdd22bb7aa52 | 416 | /* Decrement the loop counter */ |
emilmont | 1:fdd22bb7aa52 | 417 | tapCnt--; |
emilmont | 1:fdd22bb7aa52 | 418 | } |
emilmont | 1:fdd22bb7aa52 | 419 | |
emilmont | 1:fdd22bb7aa52 | 420 | /* If the filter length is not a multiple of 4, compute the remaining filter taps */ |
emilmont | 1:fdd22bb7aa52 | 421 | tapCnt = numTaps % 0x4u; |
emilmont | 1:fdd22bb7aa52 | 422 | |
emilmont | 1:fdd22bb7aa52 | 423 | while(tapCnt > 0u) |
emilmont | 1:fdd22bb7aa52 | 424 | { |
emilmont | 1:fdd22bb7aa52 | 425 | /* Read coefficients */ |
emilmont | 1:fdd22bb7aa52 | 426 | c0 = *pb++; |
emilmont | 1:fdd22bb7aa52 | 427 | |
emilmont | 1:fdd22bb7aa52 | 428 | /* Fetch 1 state variable */ |
emilmont | 1:fdd22bb7aa52 | 429 | x0 = *px0++; |
emilmont | 1:fdd22bb7aa52 | 430 | x1 = *px1++; |
emilmont | 1:fdd22bb7aa52 | 431 | |
emilmont | 1:fdd22bb7aa52 | 432 | /* Perform the multiply-accumulate */ |
emilmont | 1:fdd22bb7aa52 | 433 | acc0 += x0 * c0; |
emilmont | 1:fdd22bb7aa52 | 434 | acc1 += x1 * c0; |
emilmont | 1:fdd22bb7aa52 | 435 | |
emilmont | 1:fdd22bb7aa52 | 436 | /* Decrement the loop counter */ |
emilmont | 1:fdd22bb7aa52 | 437 | tapCnt--; |
emilmont | 1:fdd22bb7aa52 | 438 | } |
emilmont | 1:fdd22bb7aa52 | 439 | |
emilmont | 1:fdd22bb7aa52 | 440 | /* Advance the state pointer by the decimation factor |
emilmont | 1:fdd22bb7aa52 | 441 | * to process the next group of decimation factor number samples */ |
emilmont | 1:fdd22bb7aa52 | 442 | pState = pState + S->M * 2; |
emilmont | 1:fdd22bb7aa52 | 443 | |
emilmont | 1:fdd22bb7aa52 | 444 | /* Store filter output, smlad returns the values in 2.14 format */ |
emilmont | 1:fdd22bb7aa52 | 445 | /* so downsacle by 15 to get output in 1.15 */ |
emilmont | 1:fdd22bb7aa52 | 446 | |
emilmont | 1:fdd22bb7aa52 | 447 | *pDst++ = (q15_t) (__SSAT((acc0 >> 15), 16)); |
emilmont | 1:fdd22bb7aa52 | 448 | *pDst++ = (q15_t) (__SSAT((acc1 >> 15), 16)); |
emilmont | 1:fdd22bb7aa52 | 449 | |
emilmont | 1:fdd22bb7aa52 | 450 | /* Decrement the loop counter */ |
emilmont | 1:fdd22bb7aa52 | 451 | blkCnt--; |
emilmont | 1:fdd22bb7aa52 | 452 | } |
emilmont | 1:fdd22bb7aa52 | 453 | |
emilmont | 1:fdd22bb7aa52 | 454 | while(blkCntN3 > 0u) |
emilmont | 1:fdd22bb7aa52 | 455 | { |
emilmont | 1:fdd22bb7aa52 | 456 | /* Copy decimation factor number of new input samples into the state buffer */ |
emilmont | 1:fdd22bb7aa52 | 457 | i = S->M; |
emilmont | 1:fdd22bb7aa52 | 458 | |
emilmont | 1:fdd22bb7aa52 | 459 | do |
emilmont | 1:fdd22bb7aa52 | 460 | { |
emilmont | 1:fdd22bb7aa52 | 461 | *pStateCurnt++ = *pSrc++; |
emilmont | 1:fdd22bb7aa52 | 462 | |
emilmont | 1:fdd22bb7aa52 | 463 | } while(--i); |
emilmont | 1:fdd22bb7aa52 | 464 | |
emilmont | 1:fdd22bb7aa52 | 465 | /*Set sum to zero */ |
emilmont | 1:fdd22bb7aa52 | 466 | sum0 = 0; |
emilmont | 1:fdd22bb7aa52 | 467 | |
emilmont | 1:fdd22bb7aa52 | 468 | /* Initialize state pointer */ |
emilmont | 1:fdd22bb7aa52 | 469 | px = pState; |
emilmont | 1:fdd22bb7aa52 | 470 | |
emilmont | 1:fdd22bb7aa52 | 471 | /* Initialize coeff pointer */ |
emilmont | 1:fdd22bb7aa52 | 472 | pb = pCoeffs; |
emilmont | 1:fdd22bb7aa52 | 473 | |
emilmont | 1:fdd22bb7aa52 | 474 | /* Loop unrolling. Process 4 taps at a time. */ |
emilmont | 1:fdd22bb7aa52 | 475 | tapCnt = numTaps >> 2; |
emilmont | 1:fdd22bb7aa52 | 476 | |
emilmont | 1:fdd22bb7aa52 | 477 | /* Loop over the number of taps. Unroll by a factor of 4. |
emilmont | 1:fdd22bb7aa52 | 478 | ** Repeat until we've computed numTaps-4 coefficients. */ |
emilmont | 1:fdd22bb7aa52 | 479 | while(tapCnt > 0u) |
emilmont | 1:fdd22bb7aa52 | 480 | { |
emilmont | 1:fdd22bb7aa52 | 481 | /* Read the Read b[numTaps-1] coefficients */ |
emilmont | 1:fdd22bb7aa52 | 482 | c0 = *pb++; |
emilmont | 1:fdd22bb7aa52 | 483 | |
emilmont | 1:fdd22bb7aa52 | 484 | /* Read x[n-numTaps-1] and sample */ |
emilmont | 1:fdd22bb7aa52 | 485 | x0 = *px++; |
emilmont | 1:fdd22bb7aa52 | 486 | |
emilmont | 1:fdd22bb7aa52 | 487 | /* Perform the multiply-accumulate */ |
emilmont | 1:fdd22bb7aa52 | 488 | sum0 += x0 * c0; |
emilmont | 1:fdd22bb7aa52 | 489 | |
emilmont | 1:fdd22bb7aa52 | 490 | /* Read the b[numTaps-2] coefficient */ |
emilmont | 1:fdd22bb7aa52 | 491 | c0 = *pb++; |
emilmont | 1:fdd22bb7aa52 | 492 | |
emilmont | 1:fdd22bb7aa52 | 493 | /* Read x[n-numTaps-2] and sample */ |
emilmont | 1:fdd22bb7aa52 | 494 | x0 = *px++; |
emilmont | 1:fdd22bb7aa52 | 495 | |
emilmont | 1:fdd22bb7aa52 | 496 | /* Perform the multiply-accumulate */ |
emilmont | 1:fdd22bb7aa52 | 497 | sum0 += x0 * c0; |
emilmont | 1:fdd22bb7aa52 | 498 | |
emilmont | 1:fdd22bb7aa52 | 499 | /* Read the b[numTaps-3] coefficients */ |
emilmont | 1:fdd22bb7aa52 | 500 | c0 = *pb++; |
emilmont | 1:fdd22bb7aa52 | 501 | |
emilmont | 1:fdd22bb7aa52 | 502 | /* Read x[n-numTaps-3] sample */ |
emilmont | 1:fdd22bb7aa52 | 503 | x0 = *px++; |
emilmont | 1:fdd22bb7aa52 | 504 | |
emilmont | 1:fdd22bb7aa52 | 505 | /* Perform the multiply-accumulate */ |
emilmont | 1:fdd22bb7aa52 | 506 | sum0 += x0 * c0; |
emilmont | 1:fdd22bb7aa52 | 507 | |
emilmont | 1:fdd22bb7aa52 | 508 | /* Read the b[numTaps-4] coefficient */ |
emilmont | 1:fdd22bb7aa52 | 509 | c0 = *pb++; |
emilmont | 1:fdd22bb7aa52 | 510 | |
emilmont | 1:fdd22bb7aa52 | 511 | /* Read x[n-numTaps-4] sample */ |
emilmont | 1:fdd22bb7aa52 | 512 | x0 = *px++; |
emilmont | 1:fdd22bb7aa52 | 513 | |
emilmont | 1:fdd22bb7aa52 | 514 | /* Perform the multiply-accumulate */ |
emilmont | 1:fdd22bb7aa52 | 515 | sum0 += x0 * c0; |
emilmont | 1:fdd22bb7aa52 | 516 | |
emilmont | 1:fdd22bb7aa52 | 517 | /* Decrement the loop counter */ |
emilmont | 1:fdd22bb7aa52 | 518 | tapCnt--; |
emilmont | 1:fdd22bb7aa52 | 519 | } |
emilmont | 1:fdd22bb7aa52 | 520 | |
emilmont | 1:fdd22bb7aa52 | 521 | /* If the filter length is not a multiple of 4, compute the remaining filter taps */ |
emilmont | 1:fdd22bb7aa52 | 522 | tapCnt = numTaps % 0x4u; |
emilmont | 1:fdd22bb7aa52 | 523 | |
emilmont | 1:fdd22bb7aa52 | 524 | while(tapCnt > 0u) |
emilmont | 1:fdd22bb7aa52 | 525 | { |
emilmont | 1:fdd22bb7aa52 | 526 | /* Read coefficients */ |
emilmont | 1:fdd22bb7aa52 | 527 | c0 = *pb++; |
emilmont | 1:fdd22bb7aa52 | 528 | |
emilmont | 1:fdd22bb7aa52 | 529 | /* Fetch 1 state variable */ |
emilmont | 1:fdd22bb7aa52 | 530 | x0 = *px++; |
emilmont | 1:fdd22bb7aa52 | 531 | |
emilmont | 1:fdd22bb7aa52 | 532 | /* Perform the multiply-accumulate */ |
emilmont | 1:fdd22bb7aa52 | 533 | sum0 += x0 * c0; |
emilmont | 1:fdd22bb7aa52 | 534 | |
emilmont | 1:fdd22bb7aa52 | 535 | /* Decrement the loop counter */ |
emilmont | 1:fdd22bb7aa52 | 536 | tapCnt--; |
emilmont | 1:fdd22bb7aa52 | 537 | } |
emilmont | 1:fdd22bb7aa52 | 538 | |
emilmont | 1:fdd22bb7aa52 | 539 | /* Advance the state pointer by the decimation factor |
emilmont | 1:fdd22bb7aa52 | 540 | * to process the next group of decimation factor number samples */ |
emilmont | 1:fdd22bb7aa52 | 541 | pState = pState + S->M; |
emilmont | 1:fdd22bb7aa52 | 542 | |
emilmont | 1:fdd22bb7aa52 | 543 | /* Store filter output, smlad returns the values in 2.14 format */ |
emilmont | 1:fdd22bb7aa52 | 544 | /* so downsacle by 15 to get output in 1.15 */ |
emilmont | 1:fdd22bb7aa52 | 545 | *pDst++ = (q15_t) (__SSAT((sum0 >> 15), 16)); |
emilmont | 1:fdd22bb7aa52 | 546 | |
emilmont | 1:fdd22bb7aa52 | 547 | /* Decrement the loop counter */ |
emilmont | 1:fdd22bb7aa52 | 548 | blkCntN3--; |
emilmont | 1:fdd22bb7aa52 | 549 | } |
emilmont | 1:fdd22bb7aa52 | 550 | |
emilmont | 1:fdd22bb7aa52 | 551 | /* Processing is complete. |
emilmont | 1:fdd22bb7aa52 | 552 | ** Now copy the last numTaps - 1 samples to the satrt of the state buffer. |
emilmont | 1:fdd22bb7aa52 | 553 | ** This prepares the state buffer for the next function call. */ |
emilmont | 1:fdd22bb7aa52 | 554 | |
emilmont | 1:fdd22bb7aa52 | 555 | /* Points to the start of the state buffer */ |
emilmont | 1:fdd22bb7aa52 | 556 | pStateCurnt = S->pState; |
emilmont | 1:fdd22bb7aa52 | 557 | |
emilmont | 1:fdd22bb7aa52 | 558 | i = (numTaps - 1u) >> 2u; |
emilmont | 1:fdd22bb7aa52 | 559 | |
emilmont | 1:fdd22bb7aa52 | 560 | /* copy data */ |
emilmont | 1:fdd22bb7aa52 | 561 | while(i > 0u) |
emilmont | 1:fdd22bb7aa52 | 562 | { |
emilmont | 1:fdd22bb7aa52 | 563 | *pStateCurnt++ = *pState++; |
emilmont | 1:fdd22bb7aa52 | 564 | *pStateCurnt++ = *pState++; |
emilmont | 1:fdd22bb7aa52 | 565 | *pStateCurnt++ = *pState++; |
emilmont | 1:fdd22bb7aa52 | 566 | *pStateCurnt++ = *pState++; |
emilmont | 1:fdd22bb7aa52 | 567 | |
emilmont | 1:fdd22bb7aa52 | 568 | /* Decrement the loop counter */ |
emilmont | 1:fdd22bb7aa52 | 569 | i--; |
emilmont | 1:fdd22bb7aa52 | 570 | } |
emilmont | 1:fdd22bb7aa52 | 571 | |
emilmont | 1:fdd22bb7aa52 | 572 | i = (numTaps - 1u) % 0x04u; |
emilmont | 1:fdd22bb7aa52 | 573 | |
emilmont | 1:fdd22bb7aa52 | 574 | /* copy data */ |
emilmont | 1:fdd22bb7aa52 | 575 | while(i > 0u) |
emilmont | 1:fdd22bb7aa52 | 576 | { |
emilmont | 1:fdd22bb7aa52 | 577 | *pStateCurnt++ = *pState++; |
emilmont | 1:fdd22bb7aa52 | 578 | |
emilmont | 1:fdd22bb7aa52 | 579 | /* Decrement the loop counter */ |
emilmont | 1:fdd22bb7aa52 | 580 | i--; |
emilmont | 1:fdd22bb7aa52 | 581 | } |
emilmont | 1:fdd22bb7aa52 | 582 | } |
emilmont | 1:fdd22bb7aa52 | 583 | |
emilmont | 1:fdd22bb7aa52 | 584 | |
emilmont | 2:da51fb522205 | 585 | #endif /* #ifndef UNALIGNED_SUPPORT_DISABLE */ |
emilmont | 1:fdd22bb7aa52 | 586 | |
emilmont | 1:fdd22bb7aa52 | 587 | #else |
emilmont | 1:fdd22bb7aa52 | 588 | |
emilmont | 1:fdd22bb7aa52 | 589 | |
emilmont | 1:fdd22bb7aa52 | 590 | void arm_fir_decimate_q15( |
emilmont | 1:fdd22bb7aa52 | 591 | const arm_fir_decimate_instance_q15 * S, |
emilmont | 1:fdd22bb7aa52 | 592 | q15_t * pSrc, |
emilmont | 1:fdd22bb7aa52 | 593 | q15_t * pDst, |
emilmont | 1:fdd22bb7aa52 | 594 | uint32_t blockSize) |
emilmont | 1:fdd22bb7aa52 | 595 | { |
emilmont | 1:fdd22bb7aa52 | 596 | q15_t *pState = S->pState; /* State pointer */ |
emilmont | 1:fdd22bb7aa52 | 597 | q15_t *pCoeffs = S->pCoeffs; /* Coefficient pointer */ |
emilmont | 1:fdd22bb7aa52 | 598 | q15_t *pStateCurnt; /* Points to the current sample of the state */ |
emilmont | 1:fdd22bb7aa52 | 599 | q15_t *px; /* Temporary pointer for state buffer */ |
emilmont | 1:fdd22bb7aa52 | 600 | q15_t *pb; /* Temporary pointer coefficient buffer */ |
emilmont | 1:fdd22bb7aa52 | 601 | q31_t x0, c0; /* Temporary variables to hold state and coefficient values */ |
emilmont | 1:fdd22bb7aa52 | 602 | q63_t sum0; /* Accumulators */ |
emilmont | 1:fdd22bb7aa52 | 603 | uint32_t numTaps = S->numTaps; /* Number of taps */ |
emilmont | 1:fdd22bb7aa52 | 604 | uint32_t i, blkCnt, tapCnt, outBlockSize = blockSize / S->M; /* Loop counters */ |
emilmont | 1:fdd22bb7aa52 | 605 | |
emilmont | 1:fdd22bb7aa52 | 606 | |
emilmont | 1:fdd22bb7aa52 | 607 | |
emilmont | 1:fdd22bb7aa52 | 608 | /* Run the below code for Cortex-M0 */ |
emilmont | 1:fdd22bb7aa52 | 609 | |
emilmont | 1:fdd22bb7aa52 | 610 | /* S->pState buffer contains previous frame (numTaps - 1) samples */ |
emilmont | 1:fdd22bb7aa52 | 611 | /* pStateCurnt points to the location where the new input data should be written */ |
emilmont | 1:fdd22bb7aa52 | 612 | pStateCurnt = S->pState + (numTaps - 1u); |
emilmont | 1:fdd22bb7aa52 | 613 | |
emilmont | 1:fdd22bb7aa52 | 614 | /* Total number of output samples to be computed */ |
emilmont | 1:fdd22bb7aa52 | 615 | blkCnt = outBlockSize; |
emilmont | 1:fdd22bb7aa52 | 616 | |
emilmont | 1:fdd22bb7aa52 | 617 | while(blkCnt > 0u) |
emilmont | 1:fdd22bb7aa52 | 618 | { |
emilmont | 1:fdd22bb7aa52 | 619 | /* Copy decimation factor number of new input samples into the state buffer */ |
emilmont | 1:fdd22bb7aa52 | 620 | i = S->M; |
emilmont | 1:fdd22bb7aa52 | 621 | |
emilmont | 1:fdd22bb7aa52 | 622 | do |
emilmont | 1:fdd22bb7aa52 | 623 | { |
emilmont | 1:fdd22bb7aa52 | 624 | *pStateCurnt++ = *pSrc++; |
emilmont | 1:fdd22bb7aa52 | 625 | |
emilmont | 1:fdd22bb7aa52 | 626 | } while(--i); |
emilmont | 1:fdd22bb7aa52 | 627 | |
emilmont | 1:fdd22bb7aa52 | 628 | /*Set sum to zero */ |
emilmont | 1:fdd22bb7aa52 | 629 | sum0 = 0; |
emilmont | 1:fdd22bb7aa52 | 630 | |
emilmont | 1:fdd22bb7aa52 | 631 | /* Initialize state pointer */ |
emilmont | 1:fdd22bb7aa52 | 632 | px = pState; |
emilmont | 1:fdd22bb7aa52 | 633 | |
emilmont | 1:fdd22bb7aa52 | 634 | /* Initialize coeff pointer */ |
emilmont | 1:fdd22bb7aa52 | 635 | pb = pCoeffs; |
emilmont | 1:fdd22bb7aa52 | 636 | |
emilmont | 1:fdd22bb7aa52 | 637 | tapCnt = numTaps; |
emilmont | 1:fdd22bb7aa52 | 638 | |
emilmont | 1:fdd22bb7aa52 | 639 | while(tapCnt > 0u) |
emilmont | 1:fdd22bb7aa52 | 640 | { |
emilmont | 1:fdd22bb7aa52 | 641 | /* Read coefficients */ |
emilmont | 1:fdd22bb7aa52 | 642 | c0 = *pb++; |
emilmont | 1:fdd22bb7aa52 | 643 | |
emilmont | 1:fdd22bb7aa52 | 644 | /* Fetch 1 state variable */ |
emilmont | 1:fdd22bb7aa52 | 645 | x0 = *px++; |
emilmont | 1:fdd22bb7aa52 | 646 | |
emilmont | 1:fdd22bb7aa52 | 647 | /* Perform the multiply-accumulate */ |
emilmont | 1:fdd22bb7aa52 | 648 | sum0 += (q31_t) x0 *c0; |
emilmont | 1:fdd22bb7aa52 | 649 | |
emilmont | 1:fdd22bb7aa52 | 650 | /* Decrement the loop counter */ |
emilmont | 1:fdd22bb7aa52 | 651 | tapCnt--; |
emilmont | 1:fdd22bb7aa52 | 652 | } |
emilmont | 1:fdd22bb7aa52 | 653 | |
emilmont | 1:fdd22bb7aa52 | 654 | /* Advance the state pointer by the decimation factor |
emilmont | 1:fdd22bb7aa52 | 655 | * to process the next group of decimation factor number samples */ |
emilmont | 1:fdd22bb7aa52 | 656 | pState = pState + S->M; |
emilmont | 1:fdd22bb7aa52 | 657 | |
emilmont | 1:fdd22bb7aa52 | 658 | /*Store filter output , smlad will return the values in 2.14 format */ |
emilmont | 1:fdd22bb7aa52 | 659 | /* so downsacle by 15 to get output in 1.15 */ |
emilmont | 1:fdd22bb7aa52 | 660 | *pDst++ = (q15_t) (__SSAT((sum0 >> 15), 16)); |
emilmont | 1:fdd22bb7aa52 | 661 | |
emilmont | 1:fdd22bb7aa52 | 662 | /* Decrement the loop counter */ |
emilmont | 1:fdd22bb7aa52 | 663 | blkCnt--; |
emilmont | 1:fdd22bb7aa52 | 664 | } |
emilmont | 1:fdd22bb7aa52 | 665 | |
emilmont | 1:fdd22bb7aa52 | 666 | /* Processing is complete. |
emilmont | 1:fdd22bb7aa52 | 667 | ** Now copy the last numTaps - 1 samples to the start of the state buffer. |
emilmont | 1:fdd22bb7aa52 | 668 | ** This prepares the state buffer for the next function call. */ |
emilmont | 1:fdd22bb7aa52 | 669 | |
emilmont | 1:fdd22bb7aa52 | 670 | /* Points to the start of the state buffer */ |
emilmont | 1:fdd22bb7aa52 | 671 | pStateCurnt = S->pState; |
emilmont | 1:fdd22bb7aa52 | 672 | |
emilmont | 1:fdd22bb7aa52 | 673 | i = numTaps - 1u; |
emilmont | 1:fdd22bb7aa52 | 674 | |
emilmont | 1:fdd22bb7aa52 | 675 | /* copy data */ |
emilmont | 1:fdd22bb7aa52 | 676 | while(i > 0u) |
emilmont | 1:fdd22bb7aa52 | 677 | { |
emilmont | 1:fdd22bb7aa52 | 678 | *pStateCurnt++ = *pState++; |
emilmont | 1:fdd22bb7aa52 | 679 | |
emilmont | 1:fdd22bb7aa52 | 680 | /* Decrement the loop counter */ |
emilmont | 1:fdd22bb7aa52 | 681 | i--; |
emilmont | 1:fdd22bb7aa52 | 682 | } |
emilmont | 1:fdd22bb7aa52 | 683 | |
emilmont | 1:fdd22bb7aa52 | 684 | |
emilmont | 1:fdd22bb7aa52 | 685 | } |
emilmont | 1:fdd22bb7aa52 | 686 | #endif /* #ifndef ARM_MATH_CM0 */ |
emilmont | 1:fdd22bb7aa52 | 687 | |
emilmont | 1:fdd22bb7aa52 | 688 | |
emilmont | 1:fdd22bb7aa52 | 689 | /** |
emilmont | 1:fdd22bb7aa52 | 690 | * @} end of FIR_decimate group |
emilmont | 1:fdd22bb7aa52 | 691 | */ |