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_lattice_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_lattice_q31.c
emh203 0:3d9c67d97d6f 9 *
emh203 0:3d9c67d97d6f 10 * Description: Q31 FIR lattice filter processing function.
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_Lattice
emh203 0:3d9c67d97d6f 49 * @{
emh203 0:3d9c67d97d6f 50 */
emh203 0:3d9c67d97d6f 51
emh203 0:3d9c67d97d6f 52
emh203 0:3d9c67d97d6f 53 /**
emh203 0:3d9c67d97d6f 54 * @brief Processing function for the Q31 FIR lattice filter.
emh203 0:3d9c67d97d6f 55 * @param[in] *S points to an instance of the Q31 FIR lattice structure.
emh203 0:3d9c67d97d6f 56 * @param[in] *pSrc points to the block of input data.
emh203 0:3d9c67d97d6f 57 * @param[out] *pDst points to the block of output data
emh203 0:3d9c67d97d6f 58 * @param[in] blockSize number of samples to process.
emh203 0:3d9c67d97d6f 59 * @return none.
emh203 0:3d9c67d97d6f 60 *
emh203 0:3d9c67d97d6f 61 * @details
emh203 0:3d9c67d97d6f 62 * <b>Scaling and Overflow Behavior:</b>
emh203 0:3d9c67d97d6f 63 * In order to avoid overflows the input signal must be scaled down by 2*log2(numStages) bits.
emh203 0:3d9c67d97d6f 64 */
emh203 0:3d9c67d97d6f 65
emh203 0:3d9c67d97d6f 66 #ifndef ARM_MATH_CM0_FAMILY
emh203 0:3d9c67d97d6f 67
emh203 0:3d9c67d97d6f 68 /* Run the below code for Cortex-M4 and Cortex-M3 */
emh203 0:3d9c67d97d6f 69
emh203 0:3d9c67d97d6f 70 void arm_fir_lattice_q31(
emh203 0:3d9c67d97d6f 71 const arm_fir_lattice_instance_q31 * S,
emh203 0:3d9c67d97d6f 72 q31_t * pSrc,
emh203 0:3d9c67d97d6f 73 q31_t * pDst,
emh203 0:3d9c67d97d6f 74 uint32_t blockSize)
emh203 0:3d9c67d97d6f 75 {
emh203 0:3d9c67d97d6f 76 q31_t *pState; /* State pointer */
emh203 0:3d9c67d97d6f 77 q31_t *pCoeffs = S->pCoeffs; /* Coefficient pointer */
emh203 0:3d9c67d97d6f 78 q31_t *px; /* temporary state pointer */
emh203 0:3d9c67d97d6f 79 q31_t *pk; /* temporary coefficient pointer */
emh203 0:3d9c67d97d6f 80 q31_t fcurr1, fnext1, gcurr1 = 0, gnext1; /* temporary variables for first sample in loop unrolling */
emh203 0:3d9c67d97d6f 81 q31_t fcurr2, fnext2, gnext2; /* temporary variables for second sample in loop unrolling */
emh203 0:3d9c67d97d6f 82 uint32_t numStages = S->numStages; /* Length of the filter */
emh203 0:3d9c67d97d6f 83 uint32_t blkCnt, stageCnt; /* temporary variables for counts */
emh203 0:3d9c67d97d6f 84 q31_t k;
emh203 0:3d9c67d97d6f 85
emh203 0:3d9c67d97d6f 86 pState = &S->pState[0];
emh203 0:3d9c67d97d6f 87
emh203 0:3d9c67d97d6f 88 blkCnt = blockSize >> 1u;
emh203 0:3d9c67d97d6f 89
emh203 0:3d9c67d97d6f 90 /* First part of the processing with loop unrolling. Compute 2 outputs at a time.
emh203 0:3d9c67d97d6f 91 a second loop below computes the remaining 1 sample. */
emh203 0:3d9c67d97d6f 92 while(blkCnt > 0u)
emh203 0:3d9c67d97d6f 93 {
emh203 0:3d9c67d97d6f 94 /* f0(n) = x(n) */
emh203 0:3d9c67d97d6f 95 fcurr1 = *pSrc++;
emh203 0:3d9c67d97d6f 96
emh203 0:3d9c67d97d6f 97 /* f0(n) = x(n) */
emh203 0:3d9c67d97d6f 98 fcurr2 = *pSrc++;
emh203 0:3d9c67d97d6f 99
emh203 0:3d9c67d97d6f 100 /* Initialize coeff pointer */
emh203 0:3d9c67d97d6f 101 pk = (pCoeffs);
emh203 0:3d9c67d97d6f 102
emh203 0:3d9c67d97d6f 103 /* Initialize state pointer */
emh203 0:3d9c67d97d6f 104 px = pState;
emh203 0:3d9c67d97d6f 105
emh203 0:3d9c67d97d6f 106 /* read g0(n - 1) from state buffer */
emh203 0:3d9c67d97d6f 107 gcurr1 = *px;
emh203 0:3d9c67d97d6f 108
emh203 0:3d9c67d97d6f 109 /* Read the reflection coefficient */
emh203 0:3d9c67d97d6f 110 k = *pk++;
emh203 0:3d9c67d97d6f 111
emh203 0:3d9c67d97d6f 112 /* for sample 1 processing */
emh203 0:3d9c67d97d6f 113 /* f1(n) = f0(n) + K1 * g0(n-1) */
emh203 0:3d9c67d97d6f 114 fnext1 = (q31_t) (((q63_t) gcurr1 * k) >> 32);
emh203 0:3d9c67d97d6f 115
emh203 0:3d9c67d97d6f 116 /* g1(n) = f0(n) * K1 + g0(n-1) */
emh203 0:3d9c67d97d6f 117 gnext1 = (q31_t) (((q63_t) fcurr1 * (k)) >> 32);
emh203 0:3d9c67d97d6f 118 fnext1 = fcurr1 + (fnext1 << 1u);
emh203 0:3d9c67d97d6f 119 gnext1 = gcurr1 + (gnext1 << 1u);
emh203 0:3d9c67d97d6f 120
emh203 0:3d9c67d97d6f 121 /* for sample 1 processing */
emh203 0:3d9c67d97d6f 122 /* f1(n) = f0(n) + K1 * g0(n-1) */
emh203 0:3d9c67d97d6f 123 fnext2 = (q31_t) (((q63_t) fcurr1 * k) >> 32);
emh203 0:3d9c67d97d6f 124
emh203 0:3d9c67d97d6f 125 /* g1(n) = f0(n) * K1 + g0(n-1) */
emh203 0:3d9c67d97d6f 126 gnext2 = (q31_t) (((q63_t) fcurr2 * (k)) >> 32);
emh203 0:3d9c67d97d6f 127 fnext2 = fcurr2 + (fnext2 << 1u);
emh203 0:3d9c67d97d6f 128 gnext2 = fcurr1 + (gnext2 << 1u);
emh203 0:3d9c67d97d6f 129
emh203 0:3d9c67d97d6f 130 /* save g1(n) in state buffer */
emh203 0:3d9c67d97d6f 131 *px++ = fcurr2;
emh203 0:3d9c67d97d6f 132
emh203 0:3d9c67d97d6f 133 /* f1(n) is saved in fcurr1
emh203 0:3d9c67d97d6f 134 for next stage processing */
emh203 0:3d9c67d97d6f 135 fcurr1 = fnext1;
emh203 0:3d9c67d97d6f 136 fcurr2 = fnext2;
emh203 0:3d9c67d97d6f 137
emh203 0:3d9c67d97d6f 138 stageCnt = (numStages - 1u);
emh203 0:3d9c67d97d6f 139
emh203 0:3d9c67d97d6f 140 /* stage loop */
emh203 0:3d9c67d97d6f 141 while(stageCnt > 0u)
emh203 0:3d9c67d97d6f 142 {
emh203 0:3d9c67d97d6f 143
emh203 0:3d9c67d97d6f 144 /* Read the reflection coefficient */
emh203 0:3d9c67d97d6f 145 k = *pk++;
emh203 0:3d9c67d97d6f 146
emh203 0:3d9c67d97d6f 147 /* read g2(n) from state buffer */
emh203 0:3d9c67d97d6f 148 gcurr1 = *px;
emh203 0:3d9c67d97d6f 149
emh203 0:3d9c67d97d6f 150 /* save g1(n) in state buffer */
emh203 0:3d9c67d97d6f 151 *px++ = gnext2;
emh203 0:3d9c67d97d6f 152
emh203 0:3d9c67d97d6f 153 /* Sample processing for K2, K3.... */
emh203 0:3d9c67d97d6f 154 /* f2(n) = f1(n) + K2 * g1(n-1) */
emh203 0:3d9c67d97d6f 155 fnext1 = (q31_t) (((q63_t) gcurr1 * k) >> 32);
emh203 0:3d9c67d97d6f 156 fnext2 = (q31_t) (((q63_t) gnext1 * k) >> 32);
emh203 0:3d9c67d97d6f 157
emh203 0:3d9c67d97d6f 158 fnext1 = fcurr1 + (fnext1 << 1u);
emh203 0:3d9c67d97d6f 159 fnext2 = fcurr2 + (fnext2 << 1u);
emh203 0:3d9c67d97d6f 160
emh203 0:3d9c67d97d6f 161 /* g2(n) = f1(n) * K2 + g1(n-1) */
emh203 0:3d9c67d97d6f 162 gnext2 = (q31_t) (((q63_t) fcurr2 * (k)) >> 32);
emh203 0:3d9c67d97d6f 163 gnext2 = gnext1 + (gnext2 << 1u);
emh203 0:3d9c67d97d6f 164
emh203 0:3d9c67d97d6f 165 /* g2(n) = f1(n) * K2 + g1(n-1) */
emh203 0:3d9c67d97d6f 166 gnext1 = (q31_t) (((q63_t) fcurr1 * (k)) >> 32);
emh203 0:3d9c67d97d6f 167 gnext1 = gcurr1 + (gnext1 << 1u);
emh203 0:3d9c67d97d6f 168
emh203 0:3d9c67d97d6f 169 /* f1(n) is saved in fcurr1
emh203 0:3d9c67d97d6f 170 for next stage processing */
emh203 0:3d9c67d97d6f 171 fcurr1 = fnext1;
emh203 0:3d9c67d97d6f 172 fcurr2 = fnext2;
emh203 0:3d9c67d97d6f 173
emh203 0:3d9c67d97d6f 174 stageCnt--;
emh203 0:3d9c67d97d6f 175
emh203 0:3d9c67d97d6f 176 }
emh203 0:3d9c67d97d6f 177
emh203 0:3d9c67d97d6f 178 /* y(n) = fN(n) */
emh203 0:3d9c67d97d6f 179 *pDst++ = fcurr1;
emh203 0:3d9c67d97d6f 180 *pDst++ = fcurr2;
emh203 0:3d9c67d97d6f 181
emh203 0:3d9c67d97d6f 182 blkCnt--;
emh203 0:3d9c67d97d6f 183
emh203 0:3d9c67d97d6f 184 }
emh203 0:3d9c67d97d6f 185
emh203 0:3d9c67d97d6f 186 /* If the blockSize is not a multiple of 4, compute any remaining output samples here.
emh203 0:3d9c67d97d6f 187 ** No loop unrolling is used. */
emh203 0:3d9c67d97d6f 188 blkCnt = blockSize % 0x2u;
emh203 0:3d9c67d97d6f 189
emh203 0:3d9c67d97d6f 190 while(blkCnt > 0u)
emh203 0:3d9c67d97d6f 191 {
emh203 0:3d9c67d97d6f 192 /* f0(n) = x(n) */
emh203 0:3d9c67d97d6f 193 fcurr1 = *pSrc++;
emh203 0:3d9c67d97d6f 194
emh203 0:3d9c67d97d6f 195 /* Initialize coeff pointer */
emh203 0:3d9c67d97d6f 196 pk = (pCoeffs);
emh203 0:3d9c67d97d6f 197
emh203 0:3d9c67d97d6f 198 /* Initialize state pointer */
emh203 0:3d9c67d97d6f 199 px = pState;
emh203 0:3d9c67d97d6f 200
emh203 0:3d9c67d97d6f 201 /* read g0(n - 1) from state buffer */
emh203 0:3d9c67d97d6f 202 gcurr1 = *px;
emh203 0:3d9c67d97d6f 203
emh203 0:3d9c67d97d6f 204 /* Read the reflection coefficient */
emh203 0:3d9c67d97d6f 205 k = *pk++;
emh203 0:3d9c67d97d6f 206
emh203 0:3d9c67d97d6f 207 /* for sample 1 processing */
emh203 0:3d9c67d97d6f 208 /* f1(n) = f0(n) + K1 * g0(n-1) */
emh203 0:3d9c67d97d6f 209 fnext1 = (q31_t) (((q63_t) gcurr1 * k) >> 32);
emh203 0:3d9c67d97d6f 210 fnext1 = fcurr1 + (fnext1 << 1u);
emh203 0:3d9c67d97d6f 211
emh203 0:3d9c67d97d6f 212 /* g1(n) = f0(n) * K1 + g0(n-1) */
emh203 0:3d9c67d97d6f 213 gnext1 = (q31_t) (((q63_t) fcurr1 * (k)) >> 32);
emh203 0:3d9c67d97d6f 214 gnext1 = gcurr1 + (gnext1 << 1u);
emh203 0:3d9c67d97d6f 215
emh203 0:3d9c67d97d6f 216 /* save g1(n) in state buffer */
emh203 0:3d9c67d97d6f 217 *px++ = fcurr1;
emh203 0:3d9c67d97d6f 218
emh203 0:3d9c67d97d6f 219 /* f1(n) is saved in fcurr1
emh203 0:3d9c67d97d6f 220 for next stage processing */
emh203 0:3d9c67d97d6f 221 fcurr1 = fnext1;
emh203 0:3d9c67d97d6f 222
emh203 0:3d9c67d97d6f 223 stageCnt = (numStages - 1u);
emh203 0:3d9c67d97d6f 224
emh203 0:3d9c67d97d6f 225 /* stage loop */
emh203 0:3d9c67d97d6f 226 while(stageCnt > 0u)
emh203 0:3d9c67d97d6f 227 {
emh203 0:3d9c67d97d6f 228 /* Read the reflection coefficient */
emh203 0:3d9c67d97d6f 229 k = *pk++;
emh203 0:3d9c67d97d6f 230
emh203 0:3d9c67d97d6f 231 /* read g2(n) from state buffer */
emh203 0:3d9c67d97d6f 232 gcurr1 = *px;
emh203 0:3d9c67d97d6f 233
emh203 0:3d9c67d97d6f 234 /* save g1(n) in state buffer */
emh203 0:3d9c67d97d6f 235 *px++ = gnext1;
emh203 0:3d9c67d97d6f 236
emh203 0:3d9c67d97d6f 237 /* Sample processing for K2, K3.... */
emh203 0:3d9c67d97d6f 238 /* f2(n) = f1(n) + K2 * g1(n-1) */
emh203 0:3d9c67d97d6f 239 fnext1 = (q31_t) (((q63_t) gcurr1 * k) >> 32);
emh203 0:3d9c67d97d6f 240 fnext1 = fcurr1 + (fnext1 << 1u);
emh203 0:3d9c67d97d6f 241
emh203 0:3d9c67d97d6f 242 /* g2(n) = f1(n) * K2 + g1(n-1) */
emh203 0:3d9c67d97d6f 243 gnext1 = (q31_t) (((q63_t) fcurr1 * (k)) >> 32);
emh203 0:3d9c67d97d6f 244 gnext1 = gcurr1 + (gnext1 << 1u);
emh203 0:3d9c67d97d6f 245
emh203 0:3d9c67d97d6f 246 /* f1(n) is saved in fcurr1
emh203 0:3d9c67d97d6f 247 for next stage processing */
emh203 0:3d9c67d97d6f 248 fcurr1 = fnext1;
emh203 0:3d9c67d97d6f 249
emh203 0:3d9c67d97d6f 250 stageCnt--;
emh203 0:3d9c67d97d6f 251
emh203 0:3d9c67d97d6f 252 }
emh203 0:3d9c67d97d6f 253
emh203 0:3d9c67d97d6f 254
emh203 0:3d9c67d97d6f 255 /* y(n) = fN(n) */
emh203 0:3d9c67d97d6f 256 *pDst++ = fcurr1;
emh203 0:3d9c67d97d6f 257
emh203 0:3d9c67d97d6f 258 blkCnt--;
emh203 0:3d9c67d97d6f 259
emh203 0:3d9c67d97d6f 260 }
emh203 0:3d9c67d97d6f 261
emh203 0:3d9c67d97d6f 262
emh203 0:3d9c67d97d6f 263 }
emh203 0:3d9c67d97d6f 264
emh203 0:3d9c67d97d6f 265
emh203 0:3d9c67d97d6f 266 #else
emh203 0:3d9c67d97d6f 267
emh203 0:3d9c67d97d6f 268 /* Run the below code for Cortex-M0 */
emh203 0:3d9c67d97d6f 269
emh203 0:3d9c67d97d6f 270 void arm_fir_lattice_q31(
emh203 0:3d9c67d97d6f 271 const arm_fir_lattice_instance_q31 * S,
emh203 0:3d9c67d97d6f 272 q31_t * pSrc,
emh203 0:3d9c67d97d6f 273 q31_t * pDst,
emh203 0:3d9c67d97d6f 274 uint32_t blockSize)
emh203 0:3d9c67d97d6f 275 {
emh203 0:3d9c67d97d6f 276 q31_t *pState; /* State pointer */
emh203 0:3d9c67d97d6f 277 q31_t *pCoeffs = S->pCoeffs; /* Coefficient pointer */
emh203 0:3d9c67d97d6f 278 q31_t *px; /* temporary state pointer */
emh203 0:3d9c67d97d6f 279 q31_t *pk; /* temporary coefficient pointer */
emh203 0:3d9c67d97d6f 280 q31_t fcurr, fnext, gcurr, gnext; /* temporary variables */
emh203 0:3d9c67d97d6f 281 uint32_t numStages = S->numStages; /* Length of the filter */
emh203 0:3d9c67d97d6f 282 uint32_t blkCnt, stageCnt; /* temporary variables for counts */
emh203 0:3d9c67d97d6f 283
emh203 0:3d9c67d97d6f 284 pState = &S->pState[0];
emh203 0:3d9c67d97d6f 285
emh203 0:3d9c67d97d6f 286 blkCnt = blockSize;
emh203 0:3d9c67d97d6f 287
emh203 0:3d9c67d97d6f 288 while(blkCnt > 0u)
emh203 0:3d9c67d97d6f 289 {
emh203 0:3d9c67d97d6f 290 /* f0(n) = x(n) */
emh203 0:3d9c67d97d6f 291 fcurr = *pSrc++;
emh203 0:3d9c67d97d6f 292
emh203 0:3d9c67d97d6f 293 /* Initialize coeff pointer */
emh203 0:3d9c67d97d6f 294 pk = (pCoeffs);
emh203 0:3d9c67d97d6f 295
emh203 0:3d9c67d97d6f 296 /* Initialize state pointer */
emh203 0:3d9c67d97d6f 297 px = pState;
emh203 0:3d9c67d97d6f 298
emh203 0:3d9c67d97d6f 299 /* read g0(n-1) from state buffer */
emh203 0:3d9c67d97d6f 300 gcurr = *px;
emh203 0:3d9c67d97d6f 301
emh203 0:3d9c67d97d6f 302 /* for sample 1 processing */
emh203 0:3d9c67d97d6f 303 /* f1(n) = f0(n) + K1 * g0(n-1) */
emh203 0:3d9c67d97d6f 304 fnext = (q31_t) (((q63_t) gcurr * (*pk)) >> 31) + fcurr;
emh203 0:3d9c67d97d6f 305 /* g1(n) = f0(n) * K1 + g0(n-1) */
emh203 0:3d9c67d97d6f 306 gnext = (q31_t) (((q63_t) fcurr * (*pk++)) >> 31) + gcurr;
emh203 0:3d9c67d97d6f 307 /* save g1(n) in state buffer */
emh203 0:3d9c67d97d6f 308 *px++ = fcurr;
emh203 0:3d9c67d97d6f 309
emh203 0:3d9c67d97d6f 310 /* f1(n) is saved in fcurr1
emh203 0:3d9c67d97d6f 311 for next stage processing */
emh203 0:3d9c67d97d6f 312 fcurr = fnext;
emh203 0:3d9c67d97d6f 313
emh203 0:3d9c67d97d6f 314 stageCnt = (numStages - 1u);
emh203 0:3d9c67d97d6f 315
emh203 0:3d9c67d97d6f 316 /* stage loop */
emh203 0:3d9c67d97d6f 317 while(stageCnt > 0u)
emh203 0:3d9c67d97d6f 318 {
emh203 0:3d9c67d97d6f 319 /* read g2(n) from state buffer */
emh203 0:3d9c67d97d6f 320 gcurr = *px;
emh203 0:3d9c67d97d6f 321
emh203 0:3d9c67d97d6f 322 /* save g1(n) in state buffer */
emh203 0:3d9c67d97d6f 323 *px++ = gnext;
emh203 0:3d9c67d97d6f 324
emh203 0:3d9c67d97d6f 325 /* Sample processing for K2, K3.... */
emh203 0:3d9c67d97d6f 326 /* f2(n) = f1(n) + K2 * g1(n-1) */
emh203 0:3d9c67d97d6f 327 fnext = (q31_t) (((q63_t) gcurr * (*pk)) >> 31) + fcurr;
emh203 0:3d9c67d97d6f 328 /* g2(n) = f1(n) * K2 + g1(n-1) */
emh203 0:3d9c67d97d6f 329 gnext = (q31_t) (((q63_t) fcurr * (*pk++)) >> 31) + gcurr;
emh203 0:3d9c67d97d6f 330
emh203 0:3d9c67d97d6f 331 /* f1(n) is saved in fcurr1
emh203 0:3d9c67d97d6f 332 for next stage processing */
emh203 0:3d9c67d97d6f 333 fcurr = fnext;
emh203 0:3d9c67d97d6f 334
emh203 0:3d9c67d97d6f 335 stageCnt--;
emh203 0:3d9c67d97d6f 336
emh203 0:3d9c67d97d6f 337 }
emh203 0:3d9c67d97d6f 338
emh203 0:3d9c67d97d6f 339 /* y(n) = fN(n) */
emh203 0:3d9c67d97d6f 340 *pDst++ = fcurr;
emh203 0:3d9c67d97d6f 341
emh203 0:3d9c67d97d6f 342 blkCnt--;
emh203 0:3d9c67d97d6f 343
emh203 0:3d9c67d97d6f 344 }
emh203 0:3d9c67d97d6f 345
emh203 0:3d9c67d97d6f 346 }
emh203 0:3d9c67d97d6f 347
emh203 0:3d9c67d97d6f 348 #endif /* #ifndef ARM_MATH_CM0_FAMILY */
emh203 0:3d9c67d97d6f 349
emh203 0:3d9c67d97d6f 350
emh203 0:3d9c67d97d6f 351 /**
emh203 0:3d9c67d97d6f 352 * @} end of FIR_Lattice group
emh203 0:3d9c67d97d6f 353 */