Eli Hughes / CMSIS_DSP_401

V4.0.1 of the ARM CMSIS DSP libraries. Note that arm_bitreversal2.s, arm_cfft_f32.c and arm_rfft_fast_f32.c had to be removed. arm_bitreversal2.s will not assemble with the online tools. So, the fast f32 FFT functions are not yet available. All the other FFT functions are available.

Dependents:   MPU9150_Example fir_f32 fir_f32 MPU9150_nucleo_noni2cdev ... more

FilteringFunctions/arm_fir_decimate_q31.c@0:3d9c67d97d6f, 2014-07-28 (annotated)

Committer:
emh203
Date:
Mon Jul 28 15:03:15 2014 +0000
Revision:
0:3d9c67d97d6f
1st working commit.   Had to remove arm_bitreversal2.s     arm_cfft_f32.c and arm_rfft_fast_f32.c.    The .s will not assemble.      For now I removed these functions so we could at least have a library for the other functions.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
emh203 0:3d9c67d97d6f 1 /* ----------------------------------------------------------------------
emh203 0:3d9c67d97d6f 2 * Copyright (C) 2010-2014 ARM Limited. All rights reserved.
emh203 0:3d9c67d97d6f 3 *
emh203 0:3d9c67d97d6f 4 * $Date: 12. March 2014
emh203 0:3d9c67d97d6f 5 * $Revision: V1.4.3
emh203 0:3d9c67d97d6f 6 *
emh203 0:3d9c67d97d6f 7 * Project: CMSIS DSP Library
emh203 0:3d9c67d97d6f 8 * Title: arm_fir_decimate_q31.c
emh203 0:3d9c67d97d6f 9 *
emh203 0:3d9c67d97d6f 10 * Description: Q31 FIR Decimator.
emh203 0:3d9c67d97d6f 11 *
emh203 0:3d9c67d97d6f 12 * Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
emh203 0:3d9c67d97d6f 13 *
emh203 0:3d9c67d97d6f 14 * Redistribution and use in source and binary forms, with or without
emh203 0:3d9c67d97d6f 15 * modification, are permitted provided that the following conditions
emh203 0:3d9c67d97d6f 16 * are met:
emh203 0:3d9c67d97d6f 17 * - Redistributions of source code must retain the above copyright
emh203 0:3d9c67d97d6f 18 * notice, this list of conditions and the following disclaimer.
emh203 0:3d9c67d97d6f 19 * - Redistributions in binary form must reproduce the above copyright
emh203 0:3d9c67d97d6f 20 * notice, this list of conditions and the following disclaimer in
emh203 0:3d9c67d97d6f 21 * the documentation and/or other materials provided with the
emh203 0:3d9c67d97d6f 22 * distribution.
emh203 0:3d9c67d97d6f 23 * - Neither the name of ARM LIMITED nor the names of its contributors
emh203 0:3d9c67d97d6f 24 * may be used to endorse or promote products derived from this
emh203 0:3d9c67d97d6f 25 * software without specific prior written permission.
emh203 0:3d9c67d97d6f 26 *
emh203 0:3d9c67d97d6f 27 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
emh203 0:3d9c67d97d6f 28 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
emh203 0:3d9c67d97d6f 29 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
emh203 0:3d9c67d97d6f 30 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
emh203 0:3d9c67d97d6f 31 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
emh203 0:3d9c67d97d6f 32 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
emh203 0:3d9c67d97d6f 33 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
emh203 0:3d9c67d97d6f 34 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
emh203 0:3d9c67d97d6f 35 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
emh203 0:3d9c67d97d6f 36 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
emh203 0:3d9c67d97d6f 37 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
emh203 0:3d9c67d97d6f 38 * POSSIBILITY OF SUCH DAMAGE.
emh203 0:3d9c67d97d6f 39 * -------------------------------------------------------------------- */
emh203 0:3d9c67d97d6f 40
emh203 0:3d9c67d97d6f 41 #include "arm_math.h"
emh203 0:3d9c67d97d6f 42
emh203 0:3d9c67d97d6f 43 /**
emh203 0:3d9c67d97d6f 44 * @ingroup groupFilters
emh203 0:3d9c67d97d6f 45 */
emh203 0:3d9c67d97d6f 46
emh203 0:3d9c67d97d6f 47 /**
emh203 0:3d9c67d97d6f 48 * @addtogroup FIR_decimate
emh203 0:3d9c67d97d6f 49 * @{
emh203 0:3d9c67d97d6f 50 */
emh203 0:3d9c67d97d6f 51
emh203 0:3d9c67d97d6f 52 /**
emh203 0:3d9c67d97d6f 53 * @brief Processing function for the Q31 FIR decimator.
emh203 0:3d9c67d97d6f 54 * @param[in] *S points to an instance of the Q31 FIR decimator structure.
emh203 0:3d9c67d97d6f 55 * @param[in] *pSrc points to the block of input data.
emh203 0:3d9c67d97d6f 56 * @param[out] *pDst points to the block of output data
emh203 0:3d9c67d97d6f 57 * @param[in] blockSize number of input samples to process per call.
emh203 0:3d9c67d97d6f 58 * @return none
emh203 0:3d9c67d97d6f 59 *
emh203 0:3d9c67d97d6f 60 * <b>Scaling and Overflow Behavior:</b>
emh203 0:3d9c67d97d6f 61 * \par
emh203 0:3d9c67d97d6f 62 * The function is implemented using an internal 64-bit accumulator.
emh203 0:3d9c67d97d6f 63 * The accumulator has a 2.62 format and maintains full precision of the intermediate multiplication results but provides only a single guard bit.
emh203 0:3d9c67d97d6f 64 * Thus, if the accumulator result overflows it wraps around rather than clip.
emh203 0:3d9c67d97d6f 65 * In order to avoid overflows completely the input signal must be scaled down by log2(numTaps) bits (where log2 is read as log to the base 2).
emh203 0:3d9c67d97d6f 66 * After all multiply-accumulates are performed, the 2.62 accumulator is truncated to 1.32 format and then saturated to 1.31 format.
emh203 0:3d9c67d97d6f 67 *
emh203 0:3d9c67d97d6f 68 * \par
emh203 0:3d9c67d97d6f 69 * Refer to the function <code>arm_fir_decimate_fast_q31()</code> for a faster but less precise implementation of this function for Cortex-M3 and Cortex-M4.
emh203 0:3d9c67d97d6f 70 */
emh203 0:3d9c67d97d6f 71
emh203 0:3d9c67d97d6f 72 void arm_fir_decimate_q31(
emh203 0:3d9c67d97d6f 73 const arm_fir_decimate_instance_q31 * S,
emh203 0:3d9c67d97d6f 74 q31_t * pSrc,
emh203 0:3d9c67d97d6f 75 q31_t * pDst,
emh203 0:3d9c67d97d6f 76 uint32_t blockSize)
emh203 0:3d9c67d97d6f 77 {
emh203 0:3d9c67d97d6f 78 q31_t *pState = S->pState; /* State pointer */
emh203 0:3d9c67d97d6f 79 q31_t *pCoeffs = S->pCoeffs; /* Coefficient pointer */
emh203 0:3d9c67d97d6f 80 q31_t *pStateCurnt; /* Points to the current sample of the state */
emh203 0:3d9c67d97d6f 81 q31_t x0, c0; /* Temporary variables to hold state and coefficient values */
emh203 0:3d9c67d97d6f 82 q31_t *px; /* Temporary pointers for state buffer */
emh203 0:3d9c67d97d6f 83 q31_t *pb; /* Temporary pointers for coefficient buffer */
emh203 0:3d9c67d97d6f 84 q63_t sum0; /* Accumulator */
emh203 0:3d9c67d97d6f 85 uint32_t numTaps = S->numTaps; /* Number of taps */
emh203 0:3d9c67d97d6f 86 uint32_t i, tapCnt, blkCnt, outBlockSize = blockSize / S->M; /* Loop counters */
emh203 0:3d9c67d97d6f 87
emh203 0:3d9c67d97d6f 88
emh203 0:3d9c67d97d6f 89 #ifndef ARM_MATH_CM0_FAMILY
emh203 0:3d9c67d97d6f 90
emh203 0:3d9c67d97d6f 91 /* Run the below code for Cortex-M4 and Cortex-M3 */
emh203 0:3d9c67d97d6f 92
emh203 0:3d9c67d97d6f 93 /* S->pState buffer contains previous frame (numTaps - 1) samples */
emh203 0:3d9c67d97d6f 94 /* pStateCurnt points to the location where the new input data should be written */
emh203 0:3d9c67d97d6f 95 pStateCurnt = S->pState + (numTaps - 1u);
emh203 0:3d9c67d97d6f 96
emh203 0:3d9c67d97d6f 97 /* Total number of output samples to be computed */
emh203 0:3d9c67d97d6f 98 blkCnt = outBlockSize;
emh203 0:3d9c67d97d6f 99
emh203 0:3d9c67d97d6f 100 while(blkCnt > 0u)
emh203 0:3d9c67d97d6f 101 {
emh203 0:3d9c67d97d6f 102 /* Copy decimation factor number of new input samples into the state buffer */
emh203 0:3d9c67d97d6f 103 i = S->M;
emh203 0:3d9c67d97d6f 104
emh203 0:3d9c67d97d6f 105 do
emh203 0:3d9c67d97d6f 106 {
emh203 0:3d9c67d97d6f 107 *pStateCurnt++ = *pSrc++;
emh203 0:3d9c67d97d6f 108
emh203 0:3d9c67d97d6f 109 } while(--i);
emh203 0:3d9c67d97d6f 110
emh203 0:3d9c67d97d6f 111 /* Set accumulator to zero */
emh203 0:3d9c67d97d6f 112 sum0 = 0;
emh203 0:3d9c67d97d6f 113
emh203 0:3d9c67d97d6f 114 /* Initialize state pointer */
emh203 0:3d9c67d97d6f 115 px = pState;
emh203 0:3d9c67d97d6f 116
emh203 0:3d9c67d97d6f 117 /* Initialize coeff pointer */
emh203 0:3d9c67d97d6f 118 pb = pCoeffs;
emh203 0:3d9c67d97d6f 119
emh203 0:3d9c67d97d6f 120 /* Loop unrolling. Process 4 taps at a time. */
emh203 0:3d9c67d97d6f 121 tapCnt = numTaps >> 2;
emh203 0:3d9c67d97d6f 122
emh203 0:3d9c67d97d6f 123 /* Loop over the number of taps. Unroll by a factor of 4.
emh203 0:3d9c67d97d6f 124 ** Repeat until we've computed numTaps-4 coefficients. */
emh203 0:3d9c67d97d6f 125 while(tapCnt > 0u)
emh203 0:3d9c67d97d6f 126 {
emh203 0:3d9c67d97d6f 127 /* Read the b[numTaps-1] coefficient */
emh203 0:3d9c67d97d6f 128 c0 = *(pb++);
emh203 0:3d9c67d97d6f 129
emh203 0:3d9c67d97d6f 130 /* Read x[n-numTaps-1] sample */
emh203 0:3d9c67d97d6f 131 x0 = *(px++);
emh203 0:3d9c67d97d6f 132
emh203 0:3d9c67d97d6f 133 /* Perform the multiply-accumulate */
emh203 0:3d9c67d97d6f 134 sum0 += (q63_t) x0 *c0;
emh203 0:3d9c67d97d6f 135
emh203 0:3d9c67d97d6f 136 /* Read the b[numTaps-2] coefficient */
emh203 0:3d9c67d97d6f 137 c0 = *(pb++);
emh203 0:3d9c67d97d6f 138
emh203 0:3d9c67d97d6f 139 /* Read x[n-numTaps-2] sample */
emh203 0:3d9c67d97d6f 140 x0 = *(px++);
emh203 0:3d9c67d97d6f 141
emh203 0:3d9c67d97d6f 142 /* Perform the multiply-accumulate */
emh203 0:3d9c67d97d6f 143 sum0 += (q63_t) x0 *c0;
emh203 0:3d9c67d97d6f 144
emh203 0:3d9c67d97d6f 145 /* Read the b[numTaps-3] coefficient */
emh203 0:3d9c67d97d6f 146 c0 = *(pb++);
emh203 0:3d9c67d97d6f 147
emh203 0:3d9c67d97d6f 148 /* Read x[n-numTaps-3] sample */
emh203 0:3d9c67d97d6f 149 x0 = *(px++);
emh203 0:3d9c67d97d6f 150
emh203 0:3d9c67d97d6f 151 /* Perform the multiply-accumulate */
emh203 0:3d9c67d97d6f 152 sum0 += (q63_t) x0 *c0;
emh203 0:3d9c67d97d6f 153
emh203 0:3d9c67d97d6f 154 /* Read the b[numTaps-4] coefficient */
emh203 0:3d9c67d97d6f 155 c0 = *(pb++);
emh203 0:3d9c67d97d6f 156
emh203 0:3d9c67d97d6f 157 /* Read x[n-numTaps-4] sample */
emh203 0:3d9c67d97d6f 158 x0 = *(px++);
emh203 0:3d9c67d97d6f 159
emh203 0:3d9c67d97d6f 160 /* Perform the multiply-accumulate */
emh203 0:3d9c67d97d6f 161 sum0 += (q63_t) x0 *c0;
emh203 0:3d9c67d97d6f 162
emh203 0:3d9c67d97d6f 163 /* Decrement the loop counter */
emh203 0:3d9c67d97d6f 164 tapCnt--;
emh203 0:3d9c67d97d6f 165 }
emh203 0:3d9c67d97d6f 166
emh203 0:3d9c67d97d6f 167 /* If the filter length is not a multiple of 4, compute the remaining filter taps */
emh203 0:3d9c67d97d6f 168 tapCnt = numTaps % 0x4u;
emh203 0:3d9c67d97d6f 169
emh203 0:3d9c67d97d6f 170 while(tapCnt > 0u)
emh203 0:3d9c67d97d6f 171 {
emh203 0:3d9c67d97d6f 172 /* Read coefficients */
emh203 0:3d9c67d97d6f 173 c0 = *(pb++);
emh203 0:3d9c67d97d6f 174
emh203 0:3d9c67d97d6f 175 /* Fetch 1 state variable */
emh203 0:3d9c67d97d6f 176 x0 = *(px++);
emh203 0:3d9c67d97d6f 177
emh203 0:3d9c67d97d6f 178 /* Perform the multiply-accumulate */
emh203 0:3d9c67d97d6f 179 sum0 += (q63_t) x0 *c0;
emh203 0:3d9c67d97d6f 180
emh203 0:3d9c67d97d6f 181 /* Decrement the loop counter */
emh203 0:3d9c67d97d6f 182 tapCnt--;
emh203 0:3d9c67d97d6f 183 }
emh203 0:3d9c67d97d6f 184
emh203 0:3d9c67d97d6f 185 /* Advance the state pointer by the decimation factor
emh203 0:3d9c67d97d6f 186 * to process the next group of decimation factor number samples */
emh203 0:3d9c67d97d6f 187 pState = pState + S->M;
emh203 0:3d9c67d97d6f 188
emh203 0:3d9c67d97d6f 189 /* The result is in the accumulator, store in the destination buffer. */
emh203 0:3d9c67d97d6f 190 *pDst++ = (q31_t) (sum0 >> 31);
emh203 0:3d9c67d97d6f 191
emh203 0:3d9c67d97d6f 192 /* Decrement the loop counter */
emh203 0:3d9c67d97d6f 193 blkCnt--;
emh203 0:3d9c67d97d6f 194 }
emh203 0:3d9c67d97d6f 195
emh203 0:3d9c67d97d6f 196 /* Processing is complete.
emh203 0:3d9c67d97d6f 197 ** Now copy the last numTaps - 1 samples to the satrt of the state buffer.
emh203 0:3d9c67d97d6f 198 ** This prepares the state buffer for the next function call. */
emh203 0:3d9c67d97d6f 199
emh203 0:3d9c67d97d6f 200 /* Points to the start of the state buffer */
emh203 0:3d9c67d97d6f 201 pStateCurnt = S->pState;
emh203 0:3d9c67d97d6f 202
emh203 0:3d9c67d97d6f 203 i = (numTaps - 1u) >> 2u;
emh203 0:3d9c67d97d6f 204
emh203 0:3d9c67d97d6f 205 /* copy data */
emh203 0:3d9c67d97d6f 206 while(i > 0u)
emh203 0:3d9c67d97d6f 207 {
emh203 0:3d9c67d97d6f 208 *pStateCurnt++ = *pState++;
emh203 0:3d9c67d97d6f 209 *pStateCurnt++ = *pState++;
emh203 0:3d9c67d97d6f 210 *pStateCurnt++ = *pState++;
emh203 0:3d9c67d97d6f 211 *pStateCurnt++ = *pState++;
emh203 0:3d9c67d97d6f 212
emh203 0:3d9c67d97d6f 213 /* Decrement the loop counter */
emh203 0:3d9c67d97d6f 214 i--;
emh203 0:3d9c67d97d6f 215 }
emh203 0:3d9c67d97d6f 216
emh203 0:3d9c67d97d6f 217 i = (numTaps - 1u) % 0x04u;
emh203 0:3d9c67d97d6f 218
emh203 0:3d9c67d97d6f 219 /* copy data */
emh203 0:3d9c67d97d6f 220 while(i > 0u)
emh203 0:3d9c67d97d6f 221 {
emh203 0:3d9c67d97d6f 222 *pStateCurnt++ = *pState++;
emh203 0:3d9c67d97d6f 223
emh203 0:3d9c67d97d6f 224 /* Decrement the loop counter */
emh203 0:3d9c67d97d6f 225 i--;
emh203 0:3d9c67d97d6f 226 }
emh203 0:3d9c67d97d6f 227
emh203 0:3d9c67d97d6f 228 #else
emh203 0:3d9c67d97d6f 229
emh203 0:3d9c67d97d6f 230 /* Run the below code for Cortex-M0 */
emh203 0:3d9c67d97d6f 231
emh203 0:3d9c67d97d6f 232 /* S->pState buffer contains previous frame (numTaps - 1) samples */
emh203 0:3d9c67d97d6f 233 /* pStateCurnt points to the location where the new input data should be written */
emh203 0:3d9c67d97d6f 234 pStateCurnt = S->pState + (numTaps - 1u);
emh203 0:3d9c67d97d6f 235
emh203 0:3d9c67d97d6f 236 /* Total number of output samples to be computed */
emh203 0:3d9c67d97d6f 237 blkCnt = outBlockSize;
emh203 0:3d9c67d97d6f 238
emh203 0:3d9c67d97d6f 239 while(blkCnt > 0u)
emh203 0:3d9c67d97d6f 240 {
emh203 0:3d9c67d97d6f 241 /* Copy decimation factor number of new input samples into the state buffer */
emh203 0:3d9c67d97d6f 242 i = S->M;
emh203 0:3d9c67d97d6f 243
emh203 0:3d9c67d97d6f 244 do
emh203 0:3d9c67d97d6f 245 {
emh203 0:3d9c67d97d6f 246 *pStateCurnt++ = *pSrc++;
emh203 0:3d9c67d97d6f 247
emh203 0:3d9c67d97d6f 248 } while(--i);
emh203 0:3d9c67d97d6f 249
emh203 0:3d9c67d97d6f 250 /* Set accumulator to zero */
emh203 0:3d9c67d97d6f 251 sum0 = 0;
emh203 0:3d9c67d97d6f 252
emh203 0:3d9c67d97d6f 253 /* Initialize state pointer */
emh203 0:3d9c67d97d6f 254 px = pState;
emh203 0:3d9c67d97d6f 255
emh203 0:3d9c67d97d6f 256 /* Initialize coeff pointer */
emh203 0:3d9c67d97d6f 257 pb = pCoeffs;
emh203 0:3d9c67d97d6f 258
emh203 0:3d9c67d97d6f 259 tapCnt = numTaps;
emh203 0:3d9c67d97d6f 260
emh203 0:3d9c67d97d6f 261 while(tapCnt > 0u)
emh203 0:3d9c67d97d6f 262 {
emh203 0:3d9c67d97d6f 263 /* Read coefficients */
emh203 0:3d9c67d97d6f 264 c0 = *pb++;
emh203 0:3d9c67d97d6f 265
emh203 0:3d9c67d97d6f 266 /* Fetch 1 state variable */
emh203 0:3d9c67d97d6f 267 x0 = *px++;
emh203 0:3d9c67d97d6f 268
emh203 0:3d9c67d97d6f 269 /* Perform the multiply-accumulate */
emh203 0:3d9c67d97d6f 270 sum0 += (q63_t) x0 *c0;
emh203 0:3d9c67d97d6f 271
emh203 0:3d9c67d97d6f 272 /* Decrement the loop counter */
emh203 0:3d9c67d97d6f 273 tapCnt--;
emh203 0:3d9c67d97d6f 274 }
emh203 0:3d9c67d97d6f 275
emh203 0:3d9c67d97d6f 276 /* Advance the state pointer by the decimation factor
emh203 0:3d9c67d97d6f 277 * to process the next group of decimation factor number samples */
emh203 0:3d9c67d97d6f 278 pState = pState + S->M;
emh203 0:3d9c67d97d6f 279
emh203 0:3d9c67d97d6f 280 /* The result is in the accumulator, store in the destination buffer. */
emh203 0:3d9c67d97d6f 281 *pDst++ = (q31_t) (sum0 >> 31);
emh203 0:3d9c67d97d6f 282
emh203 0:3d9c67d97d6f 283 /* Decrement the loop counter */
emh203 0:3d9c67d97d6f 284 blkCnt--;
emh203 0:3d9c67d97d6f 285 }
emh203 0:3d9c67d97d6f 286
emh203 0:3d9c67d97d6f 287 /* Processing is complete.
emh203 0:3d9c67d97d6f 288 ** Now copy the last numTaps - 1 samples to the start of the state buffer.
emh203 0:3d9c67d97d6f 289 ** This prepares the state buffer for the next function call. */
emh203 0:3d9c67d97d6f 290
emh203 0:3d9c67d97d6f 291 /* Points to the start of the state buffer */
emh203 0:3d9c67d97d6f 292 pStateCurnt = S->pState;
emh203 0:3d9c67d97d6f 293
emh203 0:3d9c67d97d6f 294 i = numTaps - 1u;
emh203 0:3d9c67d97d6f 295
emh203 0:3d9c67d97d6f 296 /* copy data */
emh203 0:3d9c67d97d6f 297 while(i > 0u)
emh203 0:3d9c67d97d6f 298 {
emh203 0:3d9c67d97d6f 299 *pStateCurnt++ = *pState++;
emh203 0:3d9c67d97d6f 300
emh203 0:3d9c67d97d6f 301 /* Decrement the loop counter */
emh203 0:3d9c67d97d6f 302 i--;
emh203 0:3d9c67d97d6f 303 }
emh203 0:3d9c67d97d6f 304
emh203 0:3d9c67d97d6f 305 #endif /* #ifndef ARM_MATH_CM0_FAMILY */
emh203 0:3d9c67d97d6f 306
emh203 0:3d9c67d97d6f 307 }
emh203 0:3d9c67d97d6f 308
emh203 0:3d9c67d97d6f 309 /**
emh203 0:3d9c67d97d6f 310 * @} end of FIR_decimate group
emh203 0:3d9c67d97d6f 311 */