CMSIS DSP library
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cmsis_dsp/FilteringFunctions/arm_fir_decimate_q15.c@3:7a284390b0ce, 2013-11-08 (annotated)
- Committer:
- mbed_official
- Date:
- Fri Nov 08 13:45:10 2013 +0000
- Revision:
- 3:7a284390b0ce
- Parent:
- 2:da51fb522205
Synchronized with git revision e69956aba2f68a2a26ac26b051f8d349deaa1ce8
Who changed what in which revision?
User | Revision | Line number | New contents of line |
---|---|---|---|
emilmont | 1:fdd22bb7aa52 | 1 | /* ---------------------------------------------------------------------- |
mbed_official | 3:7a284390b0ce | 2 | * Copyright (C) 2010-2013 ARM Limited. All rights reserved. |
emilmont | 1:fdd22bb7aa52 | 3 | * |
mbed_official | 3:7a284390b0ce | 4 | * $Date: 17. January 2013 |
mbed_official | 3:7a284390b0ce | 5 | * $Revision: V1.4.1 |
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 | * |
mbed_official | 3:7a284390b0ce | 14 | * Redistribution and use in source and binary forms, with or without |
mbed_official | 3:7a284390b0ce | 15 | * modification, are permitted provided that the following conditions |
mbed_official | 3:7a284390b0ce | 16 | * are met: |
mbed_official | 3:7a284390b0ce | 17 | * - Redistributions of source code must retain the above copyright |
mbed_official | 3:7a284390b0ce | 18 | * notice, this list of conditions and the following disclaimer. |
mbed_official | 3:7a284390b0ce | 19 | * - Redistributions in binary form must reproduce the above copyright |
mbed_official | 3:7a284390b0ce | 20 | * notice, this list of conditions and the following disclaimer in |
mbed_official | 3:7a284390b0ce | 21 | * the documentation and/or other materials provided with the |
mbed_official | 3:7a284390b0ce | 22 | * distribution. |
mbed_official | 3:7a284390b0ce | 23 | * - Neither the name of ARM LIMITED nor the names of its contributors |
mbed_official | 3:7a284390b0ce | 24 | * may be used to endorse or promote products derived from this |
mbed_official | 3:7a284390b0ce | 25 | * software without specific prior written permission. |
mbed_official | 3:7a284390b0ce | 26 | * |
mbed_official | 3:7a284390b0ce | 27 | * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
mbed_official | 3:7a284390b0ce | 28 | * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
mbed_official | 3:7a284390b0ce | 29 | * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS |
mbed_official | 3:7a284390b0ce | 30 | * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE |
mbed_official | 3:7a284390b0ce | 31 | * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, |
mbed_official | 3:7a284390b0ce | 32 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, |
mbed_official | 3:7a284390b0ce | 33 | * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; |
mbed_official | 3:7a284390b0ce | 34 | * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER |
mbed_official | 3:7a284390b0ce | 35 | * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
mbed_official | 3:7a284390b0ce | 36 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN |
mbed_official | 3:7a284390b0ce | 37 | * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
mbed_official | 3:7a284390b0ce | 38 | * POSSIBILITY OF SUCH DAMAGE. |
emilmont | 1:fdd22bb7aa52 | 39 | * -------------------------------------------------------------------- */ |
emilmont | 1:fdd22bb7aa52 | 40 | |
emilmont | 1:fdd22bb7aa52 | 41 | #include "arm_math.h" |
emilmont | 1:fdd22bb7aa52 | 42 | |
emilmont | 1:fdd22bb7aa52 | 43 | /** |
emilmont | 1:fdd22bb7aa52 | 44 | * @ingroup groupFilters |
emilmont | 1:fdd22bb7aa52 | 45 | */ |
emilmont | 1:fdd22bb7aa52 | 46 | |
emilmont | 1:fdd22bb7aa52 | 47 | /** |
emilmont | 1:fdd22bb7aa52 | 48 | * @addtogroup FIR_decimate |
emilmont | 1:fdd22bb7aa52 | 49 | * @{ |
emilmont | 1:fdd22bb7aa52 | 50 | */ |
emilmont | 1:fdd22bb7aa52 | 51 | |
emilmont | 1:fdd22bb7aa52 | 52 | /** |
emilmont | 1:fdd22bb7aa52 | 53 | * @brief Processing function for the Q15 FIR decimator. |
emilmont | 1:fdd22bb7aa52 | 54 | * @param[in] *S points to an instance of the Q15 FIR decimator structure. |
emilmont | 1:fdd22bb7aa52 | 55 | * @param[in] *pSrc points to the block of input data. |
emilmont | 1:fdd22bb7aa52 | 56 | * @param[out] *pDst points to the location where the output result is written. |
emilmont | 1:fdd22bb7aa52 | 57 | * @param[in] blockSize number of input samples to process per call. |
emilmont | 1:fdd22bb7aa52 | 58 | * @return none. |
emilmont | 1:fdd22bb7aa52 | 59 | * |
emilmont | 1:fdd22bb7aa52 | 60 | * <b>Scaling and Overflow Behavior:</b> |
emilmont | 1:fdd22bb7aa52 | 61 | * \par |
emilmont | 1:fdd22bb7aa52 | 62 | * The function is implemented using a 64-bit internal accumulator. |
emilmont | 1:fdd22bb7aa52 | 63 | * Both coefficients and state variables are represented in 1.15 format and multiplications yield a 2.30 result. |
emilmont | 1:fdd22bb7aa52 | 64 | * The 2.30 intermediate results are accumulated in a 64-bit accumulator in 34.30 format. |
emilmont | 1:fdd22bb7aa52 | 65 | * There is no risk of internal overflow with this approach and the full precision of intermediate multiplications is preserved. |
emilmont | 1:fdd22bb7aa52 | 66 | * After all additions have been performed, the accumulator is truncated to 34.15 format by discarding low 15 bits. |
emilmont | 1:fdd22bb7aa52 | 67 | * Lastly, the accumulator is saturated to yield a result in 1.15 format. |
emilmont | 1:fdd22bb7aa52 | 68 | * |
emilmont | 1:fdd22bb7aa52 | 69 | * \par |
emilmont | 1:fdd22bb7aa52 | 70 | * 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 | 71 | */ |
emilmont | 1:fdd22bb7aa52 | 72 | |
mbed_official | 3:7a284390b0ce | 73 | #ifndef ARM_MATH_CM0_FAMILY |
emilmont | 1:fdd22bb7aa52 | 74 | |
emilmont | 1:fdd22bb7aa52 | 75 | #ifndef UNALIGNED_SUPPORT_DISABLE |
emilmont | 1:fdd22bb7aa52 | 76 | |
emilmont | 1:fdd22bb7aa52 | 77 | void arm_fir_decimate_q15( |
emilmont | 1:fdd22bb7aa52 | 78 | const arm_fir_decimate_instance_q15 * S, |
emilmont | 1:fdd22bb7aa52 | 79 | q15_t * pSrc, |
emilmont | 1:fdd22bb7aa52 | 80 | q15_t * pDst, |
emilmont | 1:fdd22bb7aa52 | 81 | uint32_t blockSize) |
emilmont | 1:fdd22bb7aa52 | 82 | { |
emilmont | 1:fdd22bb7aa52 | 83 | q15_t *pState = S->pState; /* State pointer */ |
emilmont | 1:fdd22bb7aa52 | 84 | q15_t *pCoeffs = S->pCoeffs; /* Coefficient pointer */ |
emilmont | 1:fdd22bb7aa52 | 85 | q15_t *pStateCurnt; /* Points to the current sample of the state */ |
emilmont | 1:fdd22bb7aa52 | 86 | q15_t *px; /* Temporary pointer for state buffer */ |
emilmont | 1:fdd22bb7aa52 | 87 | q15_t *pb; /* Temporary pointer coefficient buffer */ |
emilmont | 1:fdd22bb7aa52 | 88 | q31_t x0, x1, c0, c1; /* Temporary variables to hold state and coefficient values */ |
emilmont | 1:fdd22bb7aa52 | 89 | q63_t sum0; /* Accumulators */ |
emilmont | 1:fdd22bb7aa52 | 90 | q63_t acc0, acc1; |
emilmont | 1:fdd22bb7aa52 | 91 | q15_t *px0, *px1; |
emilmont | 1:fdd22bb7aa52 | 92 | uint32_t blkCntN3; |
emilmont | 1:fdd22bb7aa52 | 93 | uint32_t numTaps = S->numTaps; /* Number of taps */ |
emilmont | 1:fdd22bb7aa52 | 94 | uint32_t i, blkCnt, tapCnt, outBlockSize = blockSize / S->M; /* Loop counters */ |
emilmont | 1:fdd22bb7aa52 | 95 | |
emilmont | 1:fdd22bb7aa52 | 96 | |
emilmont | 1:fdd22bb7aa52 | 97 | /* S->pState buffer contains previous frame (numTaps - 1) samples */ |
emilmont | 1:fdd22bb7aa52 | 98 | /* pStateCurnt points to the location where the new input data should be written */ |
emilmont | 1:fdd22bb7aa52 | 99 | pStateCurnt = S->pState + (numTaps - 1u); |
emilmont | 1:fdd22bb7aa52 | 100 | |
emilmont | 1:fdd22bb7aa52 | 101 | |
emilmont | 1:fdd22bb7aa52 | 102 | /* Total number of output samples to be computed */ |
emilmont | 1:fdd22bb7aa52 | 103 | blkCnt = outBlockSize / 2; |
emilmont | 1:fdd22bb7aa52 | 104 | blkCntN3 = outBlockSize - (2 * blkCnt); |
emilmont | 1:fdd22bb7aa52 | 105 | |
emilmont | 1:fdd22bb7aa52 | 106 | |
emilmont | 1:fdd22bb7aa52 | 107 | while(blkCnt > 0u) |
emilmont | 1:fdd22bb7aa52 | 108 | { |
emilmont | 1:fdd22bb7aa52 | 109 | /* Copy decimation factor number of new input samples into the state buffer */ |
emilmont | 1:fdd22bb7aa52 | 110 | i = 2 * S->M; |
emilmont | 1:fdd22bb7aa52 | 111 | |
emilmont | 1:fdd22bb7aa52 | 112 | do |
emilmont | 1:fdd22bb7aa52 | 113 | { |
emilmont | 1:fdd22bb7aa52 | 114 | *pStateCurnt++ = *pSrc++; |
emilmont | 1:fdd22bb7aa52 | 115 | |
emilmont | 1:fdd22bb7aa52 | 116 | } while(--i); |
emilmont | 1:fdd22bb7aa52 | 117 | |
emilmont | 1:fdd22bb7aa52 | 118 | /* Set accumulator to zero */ |
emilmont | 1:fdd22bb7aa52 | 119 | acc0 = 0; |
emilmont | 1:fdd22bb7aa52 | 120 | acc1 = 0; |
emilmont | 1:fdd22bb7aa52 | 121 | |
emilmont | 1:fdd22bb7aa52 | 122 | /* Initialize state pointer */ |
emilmont | 1:fdd22bb7aa52 | 123 | px0 = pState; |
emilmont | 1:fdd22bb7aa52 | 124 | |
emilmont | 1:fdd22bb7aa52 | 125 | px1 = pState + S->M; |
emilmont | 1:fdd22bb7aa52 | 126 | |
emilmont | 1:fdd22bb7aa52 | 127 | |
emilmont | 1:fdd22bb7aa52 | 128 | /* Initialize coeff pointer */ |
emilmont | 1:fdd22bb7aa52 | 129 | pb = pCoeffs; |
emilmont | 1:fdd22bb7aa52 | 130 | |
emilmont | 1:fdd22bb7aa52 | 131 | /* Loop unrolling. Process 4 taps at a time. */ |
emilmont | 1:fdd22bb7aa52 | 132 | tapCnt = numTaps >> 2; |
emilmont | 1:fdd22bb7aa52 | 133 | |
emilmont | 1:fdd22bb7aa52 | 134 | /* Loop over the number of taps. Unroll by a factor of 4. |
emilmont | 1:fdd22bb7aa52 | 135 | ** Repeat until we've computed numTaps-4 coefficients. */ |
emilmont | 1:fdd22bb7aa52 | 136 | while(tapCnt > 0u) |
emilmont | 1:fdd22bb7aa52 | 137 | { |
emilmont | 1:fdd22bb7aa52 | 138 | /* Read the Read b[numTaps-1] and b[numTaps-2] coefficients */ |
emilmont | 1:fdd22bb7aa52 | 139 | c0 = *__SIMD32(pb)++; |
emilmont | 1:fdd22bb7aa52 | 140 | |
emilmont | 1:fdd22bb7aa52 | 141 | /* Read x[n-numTaps-1] and x[n-numTaps-2]sample */ |
emilmont | 1:fdd22bb7aa52 | 142 | x0 = *__SIMD32(px0)++; |
emilmont | 1:fdd22bb7aa52 | 143 | |
emilmont | 1:fdd22bb7aa52 | 144 | x1 = *__SIMD32(px1)++; |
emilmont | 1:fdd22bb7aa52 | 145 | |
emilmont | 1:fdd22bb7aa52 | 146 | /* Perform the multiply-accumulate */ |
emilmont | 1:fdd22bb7aa52 | 147 | acc0 = __SMLALD(x0, c0, acc0); |
emilmont | 1:fdd22bb7aa52 | 148 | |
emilmont | 1:fdd22bb7aa52 | 149 | acc1 = __SMLALD(x1, c0, acc1); |
emilmont | 1:fdd22bb7aa52 | 150 | |
emilmont | 1:fdd22bb7aa52 | 151 | /* Read the b[numTaps-3] and b[numTaps-4] coefficient */ |
emilmont | 1:fdd22bb7aa52 | 152 | c0 = *__SIMD32(pb)++; |
emilmont | 1:fdd22bb7aa52 | 153 | |
emilmont | 1:fdd22bb7aa52 | 154 | /* Read x[n-numTaps-2] and x[n-numTaps-3] sample */ |
emilmont | 1:fdd22bb7aa52 | 155 | x0 = *__SIMD32(px0)++; |
emilmont | 1:fdd22bb7aa52 | 156 | |
emilmont | 1:fdd22bb7aa52 | 157 | x1 = *__SIMD32(px1)++; |
emilmont | 1:fdd22bb7aa52 | 158 | |
emilmont | 1:fdd22bb7aa52 | 159 | /* Perform the multiply-accumulate */ |
emilmont | 1:fdd22bb7aa52 | 160 | acc0 = __SMLALD(x0, c0, acc0); |
emilmont | 1:fdd22bb7aa52 | 161 | |
emilmont | 1:fdd22bb7aa52 | 162 | acc1 = __SMLALD(x1, c0, acc1); |
emilmont | 1:fdd22bb7aa52 | 163 | |
emilmont | 1:fdd22bb7aa52 | 164 | /* Decrement the loop counter */ |
emilmont | 1:fdd22bb7aa52 | 165 | tapCnt--; |
emilmont | 1:fdd22bb7aa52 | 166 | } |
emilmont | 1:fdd22bb7aa52 | 167 | |
emilmont | 1:fdd22bb7aa52 | 168 | /* If the filter length is not a multiple of 4, compute the remaining filter taps */ |
emilmont | 1:fdd22bb7aa52 | 169 | tapCnt = numTaps % 0x4u; |
emilmont | 1:fdd22bb7aa52 | 170 | |
emilmont | 1:fdd22bb7aa52 | 171 | while(tapCnt > 0u) |
emilmont | 1:fdd22bb7aa52 | 172 | { |
emilmont | 1:fdd22bb7aa52 | 173 | /* Read coefficients */ |
emilmont | 1:fdd22bb7aa52 | 174 | c0 = *pb++; |
emilmont | 1:fdd22bb7aa52 | 175 | |
emilmont | 1:fdd22bb7aa52 | 176 | /* Fetch 1 state variable */ |
emilmont | 1:fdd22bb7aa52 | 177 | x0 = *px0++; |
emilmont | 1:fdd22bb7aa52 | 178 | |
emilmont | 1:fdd22bb7aa52 | 179 | x1 = *px1++; |
emilmont | 1:fdd22bb7aa52 | 180 | |
emilmont | 1:fdd22bb7aa52 | 181 | /* Perform the multiply-accumulate */ |
emilmont | 1:fdd22bb7aa52 | 182 | acc0 = __SMLALD(x0, c0, acc0); |
emilmont | 1:fdd22bb7aa52 | 183 | acc1 = __SMLALD(x1, c0, acc1); |
emilmont | 1:fdd22bb7aa52 | 184 | |
emilmont | 1:fdd22bb7aa52 | 185 | /* Decrement the loop counter */ |
emilmont | 1:fdd22bb7aa52 | 186 | tapCnt--; |
emilmont | 1:fdd22bb7aa52 | 187 | } |
emilmont | 1:fdd22bb7aa52 | 188 | |
emilmont | 1:fdd22bb7aa52 | 189 | /* Advance the state pointer by the decimation factor |
emilmont | 1:fdd22bb7aa52 | 190 | * to process the next group of decimation factor number samples */ |
emilmont | 1:fdd22bb7aa52 | 191 | pState = pState + S->M * 2; |
emilmont | 1:fdd22bb7aa52 | 192 | |
emilmont | 1:fdd22bb7aa52 | 193 | /* Store filter output, smlad returns the values in 2.14 format */ |
emilmont | 1:fdd22bb7aa52 | 194 | /* so downsacle by 15 to get output in 1.15 */ |
emilmont | 1:fdd22bb7aa52 | 195 | *pDst++ = (q15_t) (__SSAT((acc0 >> 15), 16)); |
emilmont | 1:fdd22bb7aa52 | 196 | *pDst++ = (q15_t) (__SSAT((acc1 >> 15), 16)); |
emilmont | 1:fdd22bb7aa52 | 197 | |
emilmont | 1:fdd22bb7aa52 | 198 | /* Decrement the loop counter */ |
emilmont | 1:fdd22bb7aa52 | 199 | blkCnt--; |
emilmont | 1:fdd22bb7aa52 | 200 | } |
emilmont | 1:fdd22bb7aa52 | 201 | |
emilmont | 1:fdd22bb7aa52 | 202 | |
emilmont | 1:fdd22bb7aa52 | 203 | |
emilmont | 1:fdd22bb7aa52 | 204 | while(blkCntN3 > 0u) |
emilmont | 1:fdd22bb7aa52 | 205 | { |
emilmont | 1:fdd22bb7aa52 | 206 | /* Copy decimation factor number of new input samples into the state buffer */ |
emilmont | 1:fdd22bb7aa52 | 207 | i = S->M; |
emilmont | 1:fdd22bb7aa52 | 208 | |
emilmont | 1:fdd22bb7aa52 | 209 | do |
emilmont | 1:fdd22bb7aa52 | 210 | { |
emilmont | 1:fdd22bb7aa52 | 211 | *pStateCurnt++ = *pSrc++; |
emilmont | 1:fdd22bb7aa52 | 212 | |
emilmont | 1:fdd22bb7aa52 | 213 | } while(--i); |
emilmont | 1:fdd22bb7aa52 | 214 | |
emilmont | 1:fdd22bb7aa52 | 215 | /*Set sum to zero */ |
emilmont | 1:fdd22bb7aa52 | 216 | sum0 = 0; |
emilmont | 1:fdd22bb7aa52 | 217 | |
emilmont | 1:fdd22bb7aa52 | 218 | /* Initialize state pointer */ |
emilmont | 1:fdd22bb7aa52 | 219 | px = pState; |
emilmont | 1:fdd22bb7aa52 | 220 | |
emilmont | 1:fdd22bb7aa52 | 221 | /* Initialize coeff pointer */ |
emilmont | 1:fdd22bb7aa52 | 222 | pb = pCoeffs; |
emilmont | 1:fdd22bb7aa52 | 223 | |
emilmont | 1:fdd22bb7aa52 | 224 | /* Loop unrolling. Process 4 taps at a time. */ |
emilmont | 1:fdd22bb7aa52 | 225 | tapCnt = numTaps >> 2; |
emilmont | 1:fdd22bb7aa52 | 226 | |
emilmont | 1:fdd22bb7aa52 | 227 | /* Loop over the number of taps. Unroll by a factor of 4. |
emilmont | 1:fdd22bb7aa52 | 228 | ** Repeat until we've computed numTaps-4 coefficients. */ |
emilmont | 1:fdd22bb7aa52 | 229 | while(tapCnt > 0u) |
emilmont | 1:fdd22bb7aa52 | 230 | { |
emilmont | 1:fdd22bb7aa52 | 231 | /* Read the Read b[numTaps-1] and b[numTaps-2] coefficients */ |
emilmont | 1:fdd22bb7aa52 | 232 | c0 = *__SIMD32(pb)++; |
emilmont | 1:fdd22bb7aa52 | 233 | |
emilmont | 1:fdd22bb7aa52 | 234 | /* Read x[n-numTaps-1] and x[n-numTaps-2]sample */ |
emilmont | 1:fdd22bb7aa52 | 235 | x0 = *__SIMD32(px)++; |
emilmont | 1:fdd22bb7aa52 | 236 | |
emilmont | 1:fdd22bb7aa52 | 237 | /* Read the b[numTaps-3] and b[numTaps-4] coefficient */ |
emilmont | 1:fdd22bb7aa52 | 238 | c1 = *__SIMD32(pb)++; |
emilmont | 1:fdd22bb7aa52 | 239 | |
emilmont | 1:fdd22bb7aa52 | 240 | /* Perform the multiply-accumulate */ |
emilmont | 1:fdd22bb7aa52 | 241 | sum0 = __SMLALD(x0, c0, sum0); |
emilmont | 1:fdd22bb7aa52 | 242 | |
emilmont | 1:fdd22bb7aa52 | 243 | /* Read x[n-numTaps-2] and x[n-numTaps-3] sample */ |
emilmont | 1:fdd22bb7aa52 | 244 | x0 = *__SIMD32(px)++; |
emilmont | 1:fdd22bb7aa52 | 245 | |
emilmont | 1:fdd22bb7aa52 | 246 | /* Perform the multiply-accumulate */ |
emilmont | 1:fdd22bb7aa52 | 247 | sum0 = __SMLALD(x0, c1, sum0); |
emilmont | 1:fdd22bb7aa52 | 248 | |
emilmont | 1:fdd22bb7aa52 | 249 | /* Decrement the loop counter */ |
emilmont | 1:fdd22bb7aa52 | 250 | tapCnt--; |
emilmont | 1:fdd22bb7aa52 | 251 | } |
emilmont | 1:fdd22bb7aa52 | 252 | |
emilmont | 1:fdd22bb7aa52 | 253 | /* If the filter length is not a multiple of 4, compute the remaining filter taps */ |
emilmont | 1:fdd22bb7aa52 | 254 | tapCnt = numTaps % 0x4u; |
emilmont | 1:fdd22bb7aa52 | 255 | |
emilmont | 1:fdd22bb7aa52 | 256 | while(tapCnt > 0u) |
emilmont | 1:fdd22bb7aa52 | 257 | { |
emilmont | 1:fdd22bb7aa52 | 258 | /* Read coefficients */ |
emilmont | 1:fdd22bb7aa52 | 259 | c0 = *pb++; |
emilmont | 1:fdd22bb7aa52 | 260 | |
emilmont | 1:fdd22bb7aa52 | 261 | /* Fetch 1 state variable */ |
emilmont | 1:fdd22bb7aa52 | 262 | x0 = *px++; |
emilmont | 1:fdd22bb7aa52 | 263 | |
emilmont | 1:fdd22bb7aa52 | 264 | /* Perform the multiply-accumulate */ |
emilmont | 1:fdd22bb7aa52 | 265 | sum0 = __SMLALD(x0, c0, sum0); |
emilmont | 1:fdd22bb7aa52 | 266 | |
emilmont | 1:fdd22bb7aa52 | 267 | /* Decrement the loop counter */ |
emilmont | 1:fdd22bb7aa52 | 268 | tapCnt--; |
emilmont | 1:fdd22bb7aa52 | 269 | } |
emilmont | 1:fdd22bb7aa52 | 270 | |
emilmont | 1:fdd22bb7aa52 | 271 | /* Advance the state pointer by the decimation factor |
emilmont | 1:fdd22bb7aa52 | 272 | * to process the next group of decimation factor number samples */ |
emilmont | 1:fdd22bb7aa52 | 273 | pState = pState + S->M; |
emilmont | 1:fdd22bb7aa52 | 274 | |
emilmont | 1:fdd22bb7aa52 | 275 | /* Store filter output, smlad returns the values in 2.14 format */ |
emilmont | 1:fdd22bb7aa52 | 276 | /* so downsacle by 15 to get output in 1.15 */ |
emilmont | 1:fdd22bb7aa52 | 277 | *pDst++ = (q15_t) (__SSAT((sum0 >> 15), 16)); |
emilmont | 1:fdd22bb7aa52 | 278 | |
emilmont | 1:fdd22bb7aa52 | 279 | /* Decrement the loop counter */ |
emilmont | 1:fdd22bb7aa52 | 280 | blkCntN3--; |
emilmont | 1:fdd22bb7aa52 | 281 | } |
emilmont | 1:fdd22bb7aa52 | 282 | |
emilmont | 1:fdd22bb7aa52 | 283 | /* Processing is complete. |
emilmont | 1:fdd22bb7aa52 | 284 | ** Now copy the last numTaps - 1 samples to the satrt of the state buffer. |
emilmont | 1:fdd22bb7aa52 | 285 | ** This prepares the state buffer for the next function call. */ |
emilmont | 1:fdd22bb7aa52 | 286 | |
emilmont | 1:fdd22bb7aa52 | 287 | /* Points to the start of the state buffer */ |
emilmont | 1:fdd22bb7aa52 | 288 | pStateCurnt = S->pState; |
emilmont | 1:fdd22bb7aa52 | 289 | |
emilmont | 1:fdd22bb7aa52 | 290 | i = (numTaps - 1u) >> 2u; |
emilmont | 1:fdd22bb7aa52 | 291 | |
emilmont | 1:fdd22bb7aa52 | 292 | /* copy data */ |
emilmont | 1:fdd22bb7aa52 | 293 | while(i > 0u) |
emilmont | 1:fdd22bb7aa52 | 294 | { |
emilmont | 1:fdd22bb7aa52 | 295 | *__SIMD32(pStateCurnt)++ = *__SIMD32(pState)++; |
emilmont | 1:fdd22bb7aa52 | 296 | *__SIMD32(pStateCurnt)++ = *__SIMD32(pState)++; |
emilmont | 1:fdd22bb7aa52 | 297 | |
emilmont | 1:fdd22bb7aa52 | 298 | /* Decrement the loop counter */ |
emilmont | 1:fdd22bb7aa52 | 299 | i--; |
emilmont | 1:fdd22bb7aa52 | 300 | } |
emilmont | 1:fdd22bb7aa52 | 301 | |
emilmont | 1:fdd22bb7aa52 | 302 | i = (numTaps - 1u) % 0x04u; |
emilmont | 1:fdd22bb7aa52 | 303 | |
emilmont | 1:fdd22bb7aa52 | 304 | /* copy data */ |
emilmont | 1:fdd22bb7aa52 | 305 | while(i > 0u) |
emilmont | 1:fdd22bb7aa52 | 306 | { |
emilmont | 1:fdd22bb7aa52 | 307 | *pStateCurnt++ = *pState++; |
emilmont | 1:fdd22bb7aa52 | 308 | |
emilmont | 1:fdd22bb7aa52 | 309 | /* Decrement the loop counter */ |
emilmont | 1:fdd22bb7aa52 | 310 | i--; |
emilmont | 1:fdd22bb7aa52 | 311 | } |
emilmont | 1:fdd22bb7aa52 | 312 | } |
emilmont | 1:fdd22bb7aa52 | 313 | |
emilmont | 1:fdd22bb7aa52 | 314 | #else |
emilmont | 1:fdd22bb7aa52 | 315 | |
emilmont | 1:fdd22bb7aa52 | 316 | |
emilmont | 1:fdd22bb7aa52 | 317 | void arm_fir_decimate_q15( |
emilmont | 1:fdd22bb7aa52 | 318 | const arm_fir_decimate_instance_q15 * S, |
emilmont | 1:fdd22bb7aa52 | 319 | q15_t * pSrc, |
emilmont | 1:fdd22bb7aa52 | 320 | q15_t * pDst, |
emilmont | 1:fdd22bb7aa52 | 321 | uint32_t blockSize) |
emilmont | 1:fdd22bb7aa52 | 322 | { |
emilmont | 1:fdd22bb7aa52 | 323 | q15_t *pState = S->pState; /* State pointer */ |
emilmont | 1:fdd22bb7aa52 | 324 | q15_t *pCoeffs = S->pCoeffs; /* Coefficient pointer */ |
emilmont | 1:fdd22bb7aa52 | 325 | q15_t *pStateCurnt; /* Points to the current sample of the state */ |
emilmont | 1:fdd22bb7aa52 | 326 | q15_t *px; /* Temporary pointer for state buffer */ |
emilmont | 1:fdd22bb7aa52 | 327 | q15_t *pb; /* Temporary pointer coefficient buffer */ |
emilmont | 1:fdd22bb7aa52 | 328 | q15_t x0, x1, c0; /* Temporary variables to hold state and coefficient values */ |
emilmont | 1:fdd22bb7aa52 | 329 | q63_t sum0; /* Accumulators */ |
emilmont | 1:fdd22bb7aa52 | 330 | q63_t acc0, acc1; |
emilmont | 1:fdd22bb7aa52 | 331 | q15_t *px0, *px1; |
emilmont | 1:fdd22bb7aa52 | 332 | uint32_t blkCntN3; |
emilmont | 1:fdd22bb7aa52 | 333 | uint32_t numTaps = S->numTaps; /* Number of taps */ |
emilmont | 1:fdd22bb7aa52 | 334 | uint32_t i, blkCnt, tapCnt, outBlockSize = blockSize / S->M; /* Loop counters */ |
emilmont | 1:fdd22bb7aa52 | 335 | |
emilmont | 1:fdd22bb7aa52 | 336 | |
emilmont | 1:fdd22bb7aa52 | 337 | /* S->pState buffer contains previous frame (numTaps - 1) samples */ |
emilmont | 1:fdd22bb7aa52 | 338 | /* pStateCurnt points to the location where the new input data should be written */ |
emilmont | 1:fdd22bb7aa52 | 339 | pStateCurnt = S->pState + (numTaps - 1u); |
emilmont | 1:fdd22bb7aa52 | 340 | |
emilmont | 1:fdd22bb7aa52 | 341 | |
emilmont | 1:fdd22bb7aa52 | 342 | /* Total number of output samples to be computed */ |
emilmont | 1:fdd22bb7aa52 | 343 | blkCnt = outBlockSize / 2; |
emilmont | 1:fdd22bb7aa52 | 344 | blkCntN3 = outBlockSize - (2 * blkCnt); |
emilmont | 1:fdd22bb7aa52 | 345 | |
emilmont | 1:fdd22bb7aa52 | 346 | while(blkCnt > 0u) |
emilmont | 1:fdd22bb7aa52 | 347 | { |
emilmont | 1:fdd22bb7aa52 | 348 | /* Copy decimation factor number of new input samples into the state buffer */ |
emilmont | 1:fdd22bb7aa52 | 349 | i = 2 * S->M; |
emilmont | 1:fdd22bb7aa52 | 350 | |
emilmont | 1:fdd22bb7aa52 | 351 | do |
emilmont | 1:fdd22bb7aa52 | 352 | { |
emilmont | 1:fdd22bb7aa52 | 353 | *pStateCurnt++ = *pSrc++; |
emilmont | 1:fdd22bb7aa52 | 354 | |
emilmont | 1:fdd22bb7aa52 | 355 | } while(--i); |
emilmont | 1:fdd22bb7aa52 | 356 | |
emilmont | 1:fdd22bb7aa52 | 357 | /* Set accumulator to zero */ |
emilmont | 1:fdd22bb7aa52 | 358 | acc0 = 0; |
emilmont | 1:fdd22bb7aa52 | 359 | acc1 = 0; |
emilmont | 1:fdd22bb7aa52 | 360 | |
emilmont | 1:fdd22bb7aa52 | 361 | /* Initialize state pointer */ |
emilmont | 1:fdd22bb7aa52 | 362 | px0 = pState; |
emilmont | 1:fdd22bb7aa52 | 363 | |
emilmont | 1:fdd22bb7aa52 | 364 | px1 = pState + S->M; |
emilmont | 1:fdd22bb7aa52 | 365 | |
emilmont | 1:fdd22bb7aa52 | 366 | |
emilmont | 1:fdd22bb7aa52 | 367 | /* Initialize coeff pointer */ |
emilmont | 1:fdd22bb7aa52 | 368 | pb = pCoeffs; |
emilmont | 1:fdd22bb7aa52 | 369 | |
emilmont | 1:fdd22bb7aa52 | 370 | /* Loop unrolling. Process 4 taps at a time. */ |
emilmont | 1:fdd22bb7aa52 | 371 | tapCnt = numTaps >> 2; |
emilmont | 1:fdd22bb7aa52 | 372 | |
emilmont | 1:fdd22bb7aa52 | 373 | /* Loop over the number of taps. Unroll by a factor of 4. |
emilmont | 1:fdd22bb7aa52 | 374 | ** Repeat until we've computed numTaps-4 coefficients. */ |
emilmont | 1:fdd22bb7aa52 | 375 | while(tapCnt > 0u) |
emilmont | 1:fdd22bb7aa52 | 376 | { |
emilmont | 1:fdd22bb7aa52 | 377 | /* Read the Read b[numTaps-1] coefficients */ |
emilmont | 1:fdd22bb7aa52 | 378 | c0 = *pb++; |
emilmont | 1:fdd22bb7aa52 | 379 | |
emilmont | 1:fdd22bb7aa52 | 380 | /* Read x[n-numTaps-1] for sample 0 and for sample 1 */ |
emilmont | 1:fdd22bb7aa52 | 381 | x0 = *px0++; |
emilmont | 1:fdd22bb7aa52 | 382 | x1 = *px1++; |
emilmont | 1:fdd22bb7aa52 | 383 | |
emilmont | 1:fdd22bb7aa52 | 384 | /* Perform the multiply-accumulate */ |
emilmont | 1:fdd22bb7aa52 | 385 | acc0 += x0 * c0; |
emilmont | 1:fdd22bb7aa52 | 386 | acc1 += x1 * c0; |
emilmont | 1:fdd22bb7aa52 | 387 | |
emilmont | 1:fdd22bb7aa52 | 388 | /* Read the b[numTaps-2] coefficient */ |
emilmont | 1:fdd22bb7aa52 | 389 | c0 = *pb++; |
emilmont | 1:fdd22bb7aa52 | 390 | |
emilmont | 1:fdd22bb7aa52 | 391 | /* Read x[n-numTaps-2] for sample 0 and sample 1 */ |
emilmont | 1:fdd22bb7aa52 | 392 | x0 = *px0++; |
emilmont | 1:fdd22bb7aa52 | 393 | x1 = *px1++; |
emilmont | 1:fdd22bb7aa52 | 394 | |
emilmont | 1:fdd22bb7aa52 | 395 | /* Perform the multiply-accumulate */ |
emilmont | 1:fdd22bb7aa52 | 396 | acc0 += x0 * c0; |
emilmont | 1:fdd22bb7aa52 | 397 | acc1 += x1 * c0; |
emilmont | 1:fdd22bb7aa52 | 398 | |
emilmont | 1:fdd22bb7aa52 | 399 | /* Read the b[numTaps-3] coefficients */ |
emilmont | 1:fdd22bb7aa52 | 400 | c0 = *pb++; |
emilmont | 1:fdd22bb7aa52 | 401 | |
emilmont | 1:fdd22bb7aa52 | 402 | /* Read x[n-numTaps-3] for sample 0 and sample 1 */ |
emilmont | 1:fdd22bb7aa52 | 403 | x0 = *px0++; |
emilmont | 1:fdd22bb7aa52 | 404 | x1 = *px1++; |
emilmont | 1:fdd22bb7aa52 | 405 | |
emilmont | 1:fdd22bb7aa52 | 406 | /* Perform the multiply-accumulate */ |
emilmont | 1:fdd22bb7aa52 | 407 | acc0 += x0 * c0; |
emilmont | 1:fdd22bb7aa52 | 408 | acc1 += x1 * c0; |
emilmont | 1:fdd22bb7aa52 | 409 | |
emilmont | 1:fdd22bb7aa52 | 410 | /* Read the b[numTaps-4] coefficient */ |
emilmont | 1:fdd22bb7aa52 | 411 | c0 = *pb++; |
emilmont | 1:fdd22bb7aa52 | 412 | |
emilmont | 1:fdd22bb7aa52 | 413 | /* Read x[n-numTaps-4] for sample 0 and sample 1 */ |
emilmont | 1:fdd22bb7aa52 | 414 | x0 = *px0++; |
emilmont | 1:fdd22bb7aa52 | 415 | x1 = *px1++; |
emilmont | 1:fdd22bb7aa52 | 416 | |
emilmont | 1:fdd22bb7aa52 | 417 | /* Perform the multiply-accumulate */ |
emilmont | 1:fdd22bb7aa52 | 418 | acc0 += x0 * c0; |
emilmont | 1:fdd22bb7aa52 | 419 | acc1 += x1 * c0; |
emilmont | 1:fdd22bb7aa52 | 420 | |
emilmont | 1:fdd22bb7aa52 | 421 | /* Decrement the loop counter */ |
emilmont | 1:fdd22bb7aa52 | 422 | tapCnt--; |
emilmont | 1:fdd22bb7aa52 | 423 | } |
emilmont | 1:fdd22bb7aa52 | 424 | |
emilmont | 1:fdd22bb7aa52 | 425 | /* If the filter length is not a multiple of 4, compute the remaining filter taps */ |
emilmont | 1:fdd22bb7aa52 | 426 | tapCnt = numTaps % 0x4u; |
emilmont | 1:fdd22bb7aa52 | 427 | |
emilmont | 1:fdd22bb7aa52 | 428 | while(tapCnt > 0u) |
emilmont | 1:fdd22bb7aa52 | 429 | { |
emilmont | 1:fdd22bb7aa52 | 430 | /* Read coefficients */ |
emilmont | 1:fdd22bb7aa52 | 431 | c0 = *pb++; |
emilmont | 1:fdd22bb7aa52 | 432 | |
emilmont | 1:fdd22bb7aa52 | 433 | /* Fetch 1 state variable */ |
emilmont | 1:fdd22bb7aa52 | 434 | x0 = *px0++; |
emilmont | 1:fdd22bb7aa52 | 435 | x1 = *px1++; |
emilmont | 1:fdd22bb7aa52 | 436 | |
emilmont | 1:fdd22bb7aa52 | 437 | /* Perform the multiply-accumulate */ |
emilmont | 1:fdd22bb7aa52 | 438 | acc0 += x0 * c0; |
emilmont | 1:fdd22bb7aa52 | 439 | acc1 += x1 * c0; |
emilmont | 1:fdd22bb7aa52 | 440 | |
emilmont | 1:fdd22bb7aa52 | 441 | /* Decrement the loop counter */ |
emilmont | 1:fdd22bb7aa52 | 442 | tapCnt--; |
emilmont | 1:fdd22bb7aa52 | 443 | } |
emilmont | 1:fdd22bb7aa52 | 444 | |
emilmont | 1:fdd22bb7aa52 | 445 | /* Advance the state pointer by the decimation factor |
emilmont | 1:fdd22bb7aa52 | 446 | * to process the next group of decimation factor number samples */ |
emilmont | 1:fdd22bb7aa52 | 447 | pState = pState + S->M * 2; |
emilmont | 1:fdd22bb7aa52 | 448 | |
emilmont | 1:fdd22bb7aa52 | 449 | /* Store filter output, smlad returns the values in 2.14 format */ |
emilmont | 1:fdd22bb7aa52 | 450 | /* so downsacle by 15 to get output in 1.15 */ |
emilmont | 1:fdd22bb7aa52 | 451 | |
emilmont | 1:fdd22bb7aa52 | 452 | *pDst++ = (q15_t) (__SSAT((acc0 >> 15), 16)); |
emilmont | 1:fdd22bb7aa52 | 453 | *pDst++ = (q15_t) (__SSAT((acc1 >> 15), 16)); |
emilmont | 1:fdd22bb7aa52 | 454 | |
emilmont | 1:fdd22bb7aa52 | 455 | /* Decrement the loop counter */ |
emilmont | 1:fdd22bb7aa52 | 456 | blkCnt--; |
emilmont | 1:fdd22bb7aa52 | 457 | } |
emilmont | 1:fdd22bb7aa52 | 458 | |
emilmont | 1:fdd22bb7aa52 | 459 | while(blkCntN3 > 0u) |
emilmont | 1:fdd22bb7aa52 | 460 | { |
emilmont | 1:fdd22bb7aa52 | 461 | /* Copy decimation factor number of new input samples into the state buffer */ |
emilmont | 1:fdd22bb7aa52 | 462 | i = S->M; |
emilmont | 1:fdd22bb7aa52 | 463 | |
emilmont | 1:fdd22bb7aa52 | 464 | do |
emilmont | 1:fdd22bb7aa52 | 465 | { |
emilmont | 1:fdd22bb7aa52 | 466 | *pStateCurnt++ = *pSrc++; |
emilmont | 1:fdd22bb7aa52 | 467 | |
emilmont | 1:fdd22bb7aa52 | 468 | } while(--i); |
emilmont | 1:fdd22bb7aa52 | 469 | |
emilmont | 1:fdd22bb7aa52 | 470 | /*Set sum to zero */ |
emilmont | 1:fdd22bb7aa52 | 471 | sum0 = 0; |
emilmont | 1:fdd22bb7aa52 | 472 | |
emilmont | 1:fdd22bb7aa52 | 473 | /* Initialize state pointer */ |
emilmont | 1:fdd22bb7aa52 | 474 | px = pState; |
emilmont | 1:fdd22bb7aa52 | 475 | |
emilmont | 1:fdd22bb7aa52 | 476 | /* Initialize coeff pointer */ |
emilmont | 1:fdd22bb7aa52 | 477 | pb = pCoeffs; |
emilmont | 1:fdd22bb7aa52 | 478 | |
emilmont | 1:fdd22bb7aa52 | 479 | /* Loop unrolling. Process 4 taps at a time. */ |
emilmont | 1:fdd22bb7aa52 | 480 | tapCnt = numTaps >> 2; |
emilmont | 1:fdd22bb7aa52 | 481 | |
emilmont | 1:fdd22bb7aa52 | 482 | /* Loop over the number of taps. Unroll by a factor of 4. |
emilmont | 1:fdd22bb7aa52 | 483 | ** Repeat until we've computed numTaps-4 coefficients. */ |
emilmont | 1:fdd22bb7aa52 | 484 | while(tapCnt > 0u) |
emilmont | 1:fdd22bb7aa52 | 485 | { |
emilmont | 1:fdd22bb7aa52 | 486 | /* Read the Read b[numTaps-1] coefficients */ |
emilmont | 1:fdd22bb7aa52 | 487 | c0 = *pb++; |
emilmont | 1:fdd22bb7aa52 | 488 | |
emilmont | 1:fdd22bb7aa52 | 489 | /* Read x[n-numTaps-1] and sample */ |
emilmont | 1:fdd22bb7aa52 | 490 | x0 = *px++; |
emilmont | 1:fdd22bb7aa52 | 491 | |
emilmont | 1:fdd22bb7aa52 | 492 | /* Perform the multiply-accumulate */ |
emilmont | 1:fdd22bb7aa52 | 493 | sum0 += x0 * c0; |
emilmont | 1:fdd22bb7aa52 | 494 | |
emilmont | 1:fdd22bb7aa52 | 495 | /* Read the b[numTaps-2] coefficient */ |
emilmont | 1:fdd22bb7aa52 | 496 | c0 = *pb++; |
emilmont | 1:fdd22bb7aa52 | 497 | |
emilmont | 1:fdd22bb7aa52 | 498 | /* Read x[n-numTaps-2] and sample */ |
emilmont | 1:fdd22bb7aa52 | 499 | x0 = *px++; |
emilmont | 1:fdd22bb7aa52 | 500 | |
emilmont | 1:fdd22bb7aa52 | 501 | /* Perform the multiply-accumulate */ |
emilmont | 1:fdd22bb7aa52 | 502 | sum0 += x0 * c0; |
emilmont | 1:fdd22bb7aa52 | 503 | |
emilmont | 1:fdd22bb7aa52 | 504 | /* Read the b[numTaps-3] coefficients */ |
emilmont | 1:fdd22bb7aa52 | 505 | c0 = *pb++; |
emilmont | 1:fdd22bb7aa52 | 506 | |
emilmont | 1:fdd22bb7aa52 | 507 | /* Read x[n-numTaps-3] sample */ |
emilmont | 1:fdd22bb7aa52 | 508 | x0 = *px++; |
emilmont | 1:fdd22bb7aa52 | 509 | |
emilmont | 1:fdd22bb7aa52 | 510 | /* Perform the multiply-accumulate */ |
emilmont | 1:fdd22bb7aa52 | 511 | sum0 += x0 * c0; |
emilmont | 1:fdd22bb7aa52 | 512 | |
emilmont | 1:fdd22bb7aa52 | 513 | /* Read the b[numTaps-4] coefficient */ |
emilmont | 1:fdd22bb7aa52 | 514 | c0 = *pb++; |
emilmont | 1:fdd22bb7aa52 | 515 | |
emilmont | 1:fdd22bb7aa52 | 516 | /* Read x[n-numTaps-4] sample */ |
emilmont | 1:fdd22bb7aa52 | 517 | x0 = *px++; |
emilmont | 1:fdd22bb7aa52 | 518 | |
emilmont | 1:fdd22bb7aa52 | 519 | /* Perform the multiply-accumulate */ |
emilmont | 1:fdd22bb7aa52 | 520 | sum0 += x0 * c0; |
emilmont | 1:fdd22bb7aa52 | 521 | |
emilmont | 1:fdd22bb7aa52 | 522 | /* Decrement the loop counter */ |
emilmont | 1:fdd22bb7aa52 | 523 | tapCnt--; |
emilmont | 1:fdd22bb7aa52 | 524 | } |
emilmont | 1:fdd22bb7aa52 | 525 | |
emilmont | 1:fdd22bb7aa52 | 526 | /* If the filter length is not a multiple of 4, compute the remaining filter taps */ |
emilmont | 1:fdd22bb7aa52 | 527 | tapCnt = numTaps % 0x4u; |
emilmont | 1:fdd22bb7aa52 | 528 | |
emilmont | 1:fdd22bb7aa52 | 529 | while(tapCnt > 0u) |
emilmont | 1:fdd22bb7aa52 | 530 | { |
emilmont | 1:fdd22bb7aa52 | 531 | /* Read coefficients */ |
emilmont | 1:fdd22bb7aa52 | 532 | c0 = *pb++; |
emilmont | 1:fdd22bb7aa52 | 533 | |
emilmont | 1:fdd22bb7aa52 | 534 | /* Fetch 1 state variable */ |
emilmont | 1:fdd22bb7aa52 | 535 | x0 = *px++; |
emilmont | 1:fdd22bb7aa52 | 536 | |
emilmont | 1:fdd22bb7aa52 | 537 | /* Perform the multiply-accumulate */ |
emilmont | 1:fdd22bb7aa52 | 538 | sum0 += x0 * c0; |
emilmont | 1:fdd22bb7aa52 | 539 | |
emilmont | 1:fdd22bb7aa52 | 540 | /* Decrement the loop counter */ |
emilmont | 1:fdd22bb7aa52 | 541 | tapCnt--; |
emilmont | 1:fdd22bb7aa52 | 542 | } |
emilmont | 1:fdd22bb7aa52 | 543 | |
emilmont | 1:fdd22bb7aa52 | 544 | /* Advance the state pointer by the decimation factor |
emilmont | 1:fdd22bb7aa52 | 545 | * to process the next group of decimation factor number samples */ |
emilmont | 1:fdd22bb7aa52 | 546 | pState = pState + S->M; |
emilmont | 1:fdd22bb7aa52 | 547 | |
emilmont | 1:fdd22bb7aa52 | 548 | /* Store filter output, smlad returns the values in 2.14 format */ |
emilmont | 1:fdd22bb7aa52 | 549 | /* so downsacle by 15 to get output in 1.15 */ |
emilmont | 1:fdd22bb7aa52 | 550 | *pDst++ = (q15_t) (__SSAT((sum0 >> 15), 16)); |
emilmont | 1:fdd22bb7aa52 | 551 | |
emilmont | 1:fdd22bb7aa52 | 552 | /* Decrement the loop counter */ |
emilmont | 1:fdd22bb7aa52 | 553 | blkCntN3--; |
emilmont | 1:fdd22bb7aa52 | 554 | } |
emilmont | 1:fdd22bb7aa52 | 555 | |
emilmont | 1:fdd22bb7aa52 | 556 | /* Processing is complete. |
emilmont | 1:fdd22bb7aa52 | 557 | ** Now copy the last numTaps - 1 samples to the satrt of the state buffer. |
emilmont | 1:fdd22bb7aa52 | 558 | ** This prepares the state buffer for the next function call. */ |
emilmont | 1:fdd22bb7aa52 | 559 | |
emilmont | 1:fdd22bb7aa52 | 560 | /* Points to the start of the state buffer */ |
emilmont | 1:fdd22bb7aa52 | 561 | pStateCurnt = S->pState; |
emilmont | 1:fdd22bb7aa52 | 562 | |
emilmont | 1:fdd22bb7aa52 | 563 | i = (numTaps - 1u) >> 2u; |
emilmont | 1:fdd22bb7aa52 | 564 | |
emilmont | 1:fdd22bb7aa52 | 565 | /* copy data */ |
emilmont | 1:fdd22bb7aa52 | 566 | while(i > 0u) |
emilmont | 1:fdd22bb7aa52 | 567 | { |
emilmont | 1:fdd22bb7aa52 | 568 | *pStateCurnt++ = *pState++; |
emilmont | 1:fdd22bb7aa52 | 569 | *pStateCurnt++ = *pState++; |
emilmont | 1:fdd22bb7aa52 | 570 | *pStateCurnt++ = *pState++; |
emilmont | 1:fdd22bb7aa52 | 571 | *pStateCurnt++ = *pState++; |
emilmont | 1:fdd22bb7aa52 | 572 | |
emilmont | 1:fdd22bb7aa52 | 573 | /* Decrement the loop counter */ |
emilmont | 1:fdd22bb7aa52 | 574 | i--; |
emilmont | 1:fdd22bb7aa52 | 575 | } |
emilmont | 1:fdd22bb7aa52 | 576 | |
emilmont | 1:fdd22bb7aa52 | 577 | i = (numTaps - 1u) % 0x04u; |
emilmont | 1:fdd22bb7aa52 | 578 | |
emilmont | 1:fdd22bb7aa52 | 579 | /* copy data */ |
emilmont | 1:fdd22bb7aa52 | 580 | while(i > 0u) |
emilmont | 1:fdd22bb7aa52 | 581 | { |
emilmont | 1:fdd22bb7aa52 | 582 | *pStateCurnt++ = *pState++; |
emilmont | 1:fdd22bb7aa52 | 583 | |
emilmont | 1:fdd22bb7aa52 | 584 | /* Decrement the loop counter */ |
emilmont | 1:fdd22bb7aa52 | 585 | i--; |
emilmont | 1:fdd22bb7aa52 | 586 | } |
emilmont | 1:fdd22bb7aa52 | 587 | } |
emilmont | 1:fdd22bb7aa52 | 588 | |
emilmont | 1:fdd22bb7aa52 | 589 | |
emilmont | 2:da51fb522205 | 590 | #endif /* #ifndef UNALIGNED_SUPPORT_DISABLE */ |
emilmont | 1:fdd22bb7aa52 | 591 | |
emilmont | 1:fdd22bb7aa52 | 592 | #else |
emilmont | 1:fdd22bb7aa52 | 593 | |
emilmont | 1:fdd22bb7aa52 | 594 | |
emilmont | 1:fdd22bb7aa52 | 595 | void arm_fir_decimate_q15( |
emilmont | 1:fdd22bb7aa52 | 596 | const arm_fir_decimate_instance_q15 * S, |
emilmont | 1:fdd22bb7aa52 | 597 | q15_t * pSrc, |
emilmont | 1:fdd22bb7aa52 | 598 | q15_t * pDst, |
emilmont | 1:fdd22bb7aa52 | 599 | uint32_t blockSize) |
emilmont | 1:fdd22bb7aa52 | 600 | { |
emilmont | 1:fdd22bb7aa52 | 601 | q15_t *pState = S->pState; /* State pointer */ |
emilmont | 1:fdd22bb7aa52 | 602 | q15_t *pCoeffs = S->pCoeffs; /* Coefficient pointer */ |
emilmont | 1:fdd22bb7aa52 | 603 | q15_t *pStateCurnt; /* Points to the current sample of the state */ |
emilmont | 1:fdd22bb7aa52 | 604 | q15_t *px; /* Temporary pointer for state buffer */ |
emilmont | 1:fdd22bb7aa52 | 605 | q15_t *pb; /* Temporary pointer coefficient buffer */ |
emilmont | 1:fdd22bb7aa52 | 606 | q31_t x0, c0; /* Temporary variables to hold state and coefficient values */ |
emilmont | 1:fdd22bb7aa52 | 607 | q63_t sum0; /* Accumulators */ |
emilmont | 1:fdd22bb7aa52 | 608 | uint32_t numTaps = S->numTaps; /* Number of taps */ |
emilmont | 1:fdd22bb7aa52 | 609 | uint32_t i, blkCnt, tapCnt, outBlockSize = blockSize / S->M; /* Loop counters */ |
emilmont | 1:fdd22bb7aa52 | 610 | |
emilmont | 1:fdd22bb7aa52 | 611 | |
emilmont | 1:fdd22bb7aa52 | 612 | |
emilmont | 1:fdd22bb7aa52 | 613 | /* Run the below code for Cortex-M0 */ |
emilmont | 1:fdd22bb7aa52 | 614 | |
emilmont | 1:fdd22bb7aa52 | 615 | /* S->pState buffer contains previous frame (numTaps - 1) samples */ |
emilmont | 1:fdd22bb7aa52 | 616 | /* pStateCurnt points to the location where the new input data should be written */ |
emilmont | 1:fdd22bb7aa52 | 617 | pStateCurnt = S->pState + (numTaps - 1u); |
emilmont | 1:fdd22bb7aa52 | 618 | |
emilmont | 1:fdd22bb7aa52 | 619 | /* Total number of output samples to be computed */ |
emilmont | 1:fdd22bb7aa52 | 620 | blkCnt = outBlockSize; |
emilmont | 1:fdd22bb7aa52 | 621 | |
emilmont | 1:fdd22bb7aa52 | 622 | while(blkCnt > 0u) |
emilmont | 1:fdd22bb7aa52 | 623 | { |
emilmont | 1:fdd22bb7aa52 | 624 | /* Copy decimation factor number of new input samples into the state buffer */ |
emilmont | 1:fdd22bb7aa52 | 625 | i = S->M; |
emilmont | 1:fdd22bb7aa52 | 626 | |
emilmont | 1:fdd22bb7aa52 | 627 | do |
emilmont | 1:fdd22bb7aa52 | 628 | { |
emilmont | 1:fdd22bb7aa52 | 629 | *pStateCurnt++ = *pSrc++; |
emilmont | 1:fdd22bb7aa52 | 630 | |
emilmont | 1:fdd22bb7aa52 | 631 | } while(--i); |
emilmont | 1:fdd22bb7aa52 | 632 | |
emilmont | 1:fdd22bb7aa52 | 633 | /*Set sum to zero */ |
emilmont | 1:fdd22bb7aa52 | 634 | sum0 = 0; |
emilmont | 1:fdd22bb7aa52 | 635 | |
emilmont | 1:fdd22bb7aa52 | 636 | /* Initialize state pointer */ |
emilmont | 1:fdd22bb7aa52 | 637 | px = pState; |
emilmont | 1:fdd22bb7aa52 | 638 | |
emilmont | 1:fdd22bb7aa52 | 639 | /* Initialize coeff pointer */ |
emilmont | 1:fdd22bb7aa52 | 640 | pb = pCoeffs; |
emilmont | 1:fdd22bb7aa52 | 641 | |
emilmont | 1:fdd22bb7aa52 | 642 | tapCnt = numTaps; |
emilmont | 1:fdd22bb7aa52 | 643 | |
emilmont | 1:fdd22bb7aa52 | 644 | while(tapCnt > 0u) |
emilmont | 1:fdd22bb7aa52 | 645 | { |
emilmont | 1:fdd22bb7aa52 | 646 | /* Read coefficients */ |
emilmont | 1:fdd22bb7aa52 | 647 | c0 = *pb++; |
emilmont | 1:fdd22bb7aa52 | 648 | |
emilmont | 1:fdd22bb7aa52 | 649 | /* Fetch 1 state variable */ |
emilmont | 1:fdd22bb7aa52 | 650 | x0 = *px++; |
emilmont | 1:fdd22bb7aa52 | 651 | |
emilmont | 1:fdd22bb7aa52 | 652 | /* Perform the multiply-accumulate */ |
emilmont | 1:fdd22bb7aa52 | 653 | sum0 += (q31_t) x0 *c0; |
emilmont | 1:fdd22bb7aa52 | 654 | |
emilmont | 1:fdd22bb7aa52 | 655 | /* Decrement the loop counter */ |
emilmont | 1:fdd22bb7aa52 | 656 | tapCnt--; |
emilmont | 1:fdd22bb7aa52 | 657 | } |
emilmont | 1:fdd22bb7aa52 | 658 | |
emilmont | 1:fdd22bb7aa52 | 659 | /* Advance the state pointer by the decimation factor |
emilmont | 1:fdd22bb7aa52 | 660 | * to process the next group of decimation factor number samples */ |
emilmont | 1:fdd22bb7aa52 | 661 | pState = pState + S->M; |
emilmont | 1:fdd22bb7aa52 | 662 | |
emilmont | 1:fdd22bb7aa52 | 663 | /*Store filter output , smlad will return the values in 2.14 format */ |
emilmont | 1:fdd22bb7aa52 | 664 | /* so downsacle by 15 to get output in 1.15 */ |
emilmont | 1:fdd22bb7aa52 | 665 | *pDst++ = (q15_t) (__SSAT((sum0 >> 15), 16)); |
emilmont | 1:fdd22bb7aa52 | 666 | |
emilmont | 1:fdd22bb7aa52 | 667 | /* Decrement the loop counter */ |
emilmont | 1:fdd22bb7aa52 | 668 | blkCnt--; |
emilmont | 1:fdd22bb7aa52 | 669 | } |
emilmont | 1:fdd22bb7aa52 | 670 | |
emilmont | 1:fdd22bb7aa52 | 671 | /* Processing is complete. |
emilmont | 1:fdd22bb7aa52 | 672 | ** Now copy the last numTaps - 1 samples to the start of the state buffer. |
emilmont | 1:fdd22bb7aa52 | 673 | ** This prepares the state buffer for the next function call. */ |
emilmont | 1:fdd22bb7aa52 | 674 | |
emilmont | 1:fdd22bb7aa52 | 675 | /* Points to the start of the state buffer */ |
emilmont | 1:fdd22bb7aa52 | 676 | pStateCurnt = S->pState; |
emilmont | 1:fdd22bb7aa52 | 677 | |
emilmont | 1:fdd22bb7aa52 | 678 | i = numTaps - 1u; |
emilmont | 1:fdd22bb7aa52 | 679 | |
emilmont | 1:fdd22bb7aa52 | 680 | /* copy data */ |
emilmont | 1:fdd22bb7aa52 | 681 | while(i > 0u) |
emilmont | 1:fdd22bb7aa52 | 682 | { |
emilmont | 1:fdd22bb7aa52 | 683 | *pStateCurnt++ = *pState++; |
emilmont | 1:fdd22bb7aa52 | 684 | |
emilmont | 1:fdd22bb7aa52 | 685 | /* Decrement the loop counter */ |
emilmont | 1:fdd22bb7aa52 | 686 | i--; |
emilmont | 1:fdd22bb7aa52 | 687 | } |
emilmont | 1:fdd22bb7aa52 | 688 | |
emilmont | 1:fdd22bb7aa52 | 689 | |
emilmont | 1:fdd22bb7aa52 | 690 | } |
mbed_official | 3:7a284390b0ce | 691 | #endif /* #ifndef ARM_MATH_CM0_FAMILY */ |
emilmont | 1:fdd22bb7aa52 | 692 | |
emilmont | 1:fdd22bb7aa52 | 693 | |
emilmont | 1:fdd22bb7aa52 | 694 | /** |
emilmont | 1:fdd22bb7aa52 | 695 | * @} end of FIR_decimate group |
emilmont | 1:fdd22bb7aa52 | 696 | */ |