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_iir_lattice_f32.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_iir_lattice_f32.c
emh203 0:3d9c67d97d6f 9 *
emh203 0:3d9c67d97d6f 10 * Description: Floating-point IIR 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 * @defgroup IIR_Lattice Infinite Impulse Response (IIR) Lattice Filters
emh203 0:3d9c67d97d6f 49 *
emh203 0:3d9c67d97d6f 50 * This set of functions implements lattice filters
emh203 0:3d9c67d97d6f 51 * for Q15, Q31 and floating-point data types. Lattice filters are used in a
emh203 0:3d9c67d97d6f 52 * variety of adaptive filter applications. The filter structure has feedforward and
emh203 0:3d9c67d97d6f 53 * feedback components and the net impulse response is infinite length.
emh203 0:3d9c67d97d6f 54 * The functions operate on blocks
emh203 0:3d9c67d97d6f 55 * of input and output data and each call to the function processes
emh203 0:3d9c67d97d6f 56 * <code>blockSize</code> samples through the filter. <code>pSrc</code> and
emh203 0:3d9c67d97d6f 57 * <code>pDst</code> point to input and output arrays containing <code>blockSize</code> values.
emh203 0:3d9c67d97d6f 58
emh203 0:3d9c67d97d6f 59 * \par Algorithm:
emh203 0:3d9c67d97d6f 60 * \image html IIRLattice.gif "Infinite Impulse Response Lattice filter"
emh203 0:3d9c67d97d6f 61 * <pre>
emh203 0:3d9c67d97d6f 62 * fN(n) = x(n)
emh203 0:3d9c67d97d6f 63 * fm-1(n) = fm(n) - km * gm-1(n-1) for m = N, N-1, ...1
emh203 0:3d9c67d97d6f 64 * gm(n) = km * fm-1(n) + gm-1(n-1) for m = N, N-1, ...1
emh203 0:3d9c67d97d6f 65 * y(n) = vN * gN(n) + vN-1 * gN-1(n) + ...+ v0 * g0(n)
emh203 0:3d9c67d97d6f 66 * </pre>
emh203 0:3d9c67d97d6f 67 * \par
emh203 0:3d9c67d97d6f 68 * <code>pkCoeffs</code> points to array of reflection coefficients of size <code>numStages</code>.
emh203 0:3d9c67d97d6f 69 * Reflection coefficients are stored in time-reversed order.
emh203 0:3d9c67d97d6f 70 * \par
emh203 0:3d9c67d97d6f 71 * <pre>
emh203 0:3d9c67d97d6f 72 * {kN, kN-1, ....k1}
emh203 0:3d9c67d97d6f 73 * </pre>
emh203 0:3d9c67d97d6f 74 * <code>pvCoeffs</code> points to the array of ladder coefficients of size <code>(numStages+1)</code>.
emh203 0:3d9c67d97d6f 75 * Ladder coefficients are stored in time-reversed order.
emh203 0:3d9c67d97d6f 76 * \par
emh203 0:3d9c67d97d6f 77 * <pre>
emh203 0:3d9c67d97d6f 78 * {vN, vN-1, ...v0}
emh203 0:3d9c67d97d6f 79 * </pre>
emh203 0:3d9c67d97d6f 80 * <code>pState</code> points to a state array of size <code>numStages + blockSize</code>.
emh203 0:3d9c67d97d6f 81 * The state variables shown in the figure above (the g values) are stored in the <code>pState</code> array.
emh203 0:3d9c67d97d6f 82 * The state variables are updated after each block of data is processed; the coefficients are untouched.
emh203 0:3d9c67d97d6f 83 * \par Instance Structure
emh203 0:3d9c67d97d6f 84 * The coefficients and state variables for a filter are stored together in an instance data structure.
emh203 0:3d9c67d97d6f 85 * A separate instance structure must be defined for each filter.
emh203 0:3d9c67d97d6f 86 * Coefficient arrays may be shared among several instances while state variable arrays cannot be shared.
emh203 0:3d9c67d97d6f 87 * There are separate instance structure declarations for each of the 3 supported data types.
emh203 0:3d9c67d97d6f 88 *
emh203 0:3d9c67d97d6f 89 * \par Initialization Functions
emh203 0:3d9c67d97d6f 90 * There is also an associated initialization function for each data type.
emh203 0:3d9c67d97d6f 91 * The initialization function performs the following operations:
emh203 0:3d9c67d97d6f 92 * - Sets the values of the internal structure fields.
emh203 0:3d9c67d97d6f 93 * - Zeros out the values in the state buffer.
emh203 0:3d9c67d97d6f 94 * To do this manually without calling the init function, assign the follow subfields of the instance structure:
emh203 0:3d9c67d97d6f 95 * numStages, pkCoeffs, pvCoeffs, pState. Also set all of the values in pState to zero.
emh203 0:3d9c67d97d6f 96 *
emh203 0:3d9c67d97d6f 97 * \par
emh203 0:3d9c67d97d6f 98 * Use of the initialization function is optional.
emh203 0:3d9c67d97d6f 99 * However, if the initialization function is used, then the instance structure cannot be placed into a const data section.
emh203 0:3d9c67d97d6f 100 * To place an instance structure into a const data section, the instance structure must be manually initialized.
emh203 0:3d9c67d97d6f 101 * Set the values in the state buffer to zeros and then manually initialize the instance structure as follows:
emh203 0:3d9c67d97d6f 102 * <pre>
emh203 0:3d9c67d97d6f 103 *arm_iir_lattice_instance_f32 S = {numStages, pState, pkCoeffs, pvCoeffs};
emh203 0:3d9c67d97d6f 104 *arm_iir_lattice_instance_q31 S = {numStages, pState, pkCoeffs, pvCoeffs};
emh203 0:3d9c67d97d6f 105 *arm_iir_lattice_instance_q15 S = {numStages, pState, pkCoeffs, pvCoeffs};
emh203 0:3d9c67d97d6f 106 * </pre>
emh203 0:3d9c67d97d6f 107 * \par
emh203 0:3d9c67d97d6f 108 * where <code>numStages</code> is the number of stages in the filter; <code>pState</code> points to the state buffer array;
emh203 0:3d9c67d97d6f 109 * <code>pkCoeffs</code> points to array of the reflection coefficients; <code>pvCoeffs</code> points to the array of ladder coefficients.
emh203 0:3d9c67d97d6f 110 * \par Fixed-Point Behavior
emh203 0:3d9c67d97d6f 111 * Care must be taken when using the fixed-point versions of the IIR lattice filter functions.
emh203 0:3d9c67d97d6f 112 * In particular, the overflow and saturation behavior of the accumulator used in each function must be considered.
emh203 0:3d9c67d97d6f 113 * Refer to the function specific documentation below for usage guidelines.
emh203 0:3d9c67d97d6f 114 */
emh203 0:3d9c67d97d6f 115
emh203 0:3d9c67d97d6f 116 /**
emh203 0:3d9c67d97d6f 117 * @addtogroup IIR_Lattice
emh203 0:3d9c67d97d6f 118 * @{
emh203 0:3d9c67d97d6f 119 */
emh203 0:3d9c67d97d6f 120
emh203 0:3d9c67d97d6f 121 /**
emh203 0:3d9c67d97d6f 122 * @brief Processing function for the floating-point IIR lattice filter.
emh203 0:3d9c67d97d6f 123 * @param[in] *S points to an instance of the floating-point IIR lattice structure.
emh203 0:3d9c67d97d6f 124 * @param[in] *pSrc points to the block of input data.
emh203 0:3d9c67d97d6f 125 * @param[out] *pDst points to the block of output data.
emh203 0:3d9c67d97d6f 126 * @param[in] blockSize number of samples to process.
emh203 0:3d9c67d97d6f 127 * @return none.
emh203 0:3d9c67d97d6f 128 */
emh203 0:3d9c67d97d6f 129
emh203 0:3d9c67d97d6f 130 #ifndef ARM_MATH_CM0_FAMILY
emh203 0:3d9c67d97d6f 131
emh203 0:3d9c67d97d6f 132 /* Run the below code for Cortex-M4 and Cortex-M3 */
emh203 0:3d9c67d97d6f 133
emh203 0:3d9c67d97d6f 134 void arm_iir_lattice_f32(
emh203 0:3d9c67d97d6f 135 const arm_iir_lattice_instance_f32 * S,
emh203 0:3d9c67d97d6f 136 float32_t * pSrc,
emh203 0:3d9c67d97d6f 137 float32_t * pDst,
emh203 0:3d9c67d97d6f 138 uint32_t blockSize)
emh203 0:3d9c67d97d6f 139 {
emh203 0:3d9c67d97d6f 140 float32_t fnext1, gcurr1, gnext; /* Temporary variables for lattice stages */
emh203 0:3d9c67d97d6f 141 float32_t acc; /* Accumlator */
emh203 0:3d9c67d97d6f 142 uint32_t blkCnt, tapCnt; /* temporary variables for counts */
emh203 0:3d9c67d97d6f 143 float32_t *px1, *px2, *pk, *pv; /* temporary pointers for state and coef */
emh203 0:3d9c67d97d6f 144 uint32_t numStages = S->numStages; /* number of stages */
emh203 0:3d9c67d97d6f 145 float32_t *pState; /* State pointer */
emh203 0:3d9c67d97d6f 146 float32_t *pStateCurnt; /* State current pointer */
emh203 0:3d9c67d97d6f 147 float32_t k1, k2;
emh203 0:3d9c67d97d6f 148 float32_t v1, v2, v3, v4;
emh203 0:3d9c67d97d6f 149 float32_t gcurr2;
emh203 0:3d9c67d97d6f 150 float32_t fnext2;
emh203 0:3d9c67d97d6f 151
emh203 0:3d9c67d97d6f 152 /* initialise loop count */
emh203 0:3d9c67d97d6f 153 blkCnt = blockSize;
emh203 0:3d9c67d97d6f 154
emh203 0:3d9c67d97d6f 155 /* initialise state pointer */
emh203 0:3d9c67d97d6f 156 pState = &S->pState[0];
emh203 0:3d9c67d97d6f 157
emh203 0:3d9c67d97d6f 158 /* Sample processing */
emh203 0:3d9c67d97d6f 159 while(blkCnt > 0u)
emh203 0:3d9c67d97d6f 160 {
emh203 0:3d9c67d97d6f 161 /* Read Sample from input buffer */
emh203 0:3d9c67d97d6f 162 /* fN(n) = x(n) */
emh203 0:3d9c67d97d6f 163 fnext2 = *pSrc++;
emh203 0:3d9c67d97d6f 164
emh203 0:3d9c67d97d6f 165 /* Initialize Ladder coeff pointer */
emh203 0:3d9c67d97d6f 166 pv = &S->pvCoeffs[0];
emh203 0:3d9c67d97d6f 167 /* Initialize Reflection coeff pointer */
emh203 0:3d9c67d97d6f 168 pk = &S->pkCoeffs[0];
emh203 0:3d9c67d97d6f 169
emh203 0:3d9c67d97d6f 170 /* Initialize state read pointer */
emh203 0:3d9c67d97d6f 171 px1 = pState;
emh203 0:3d9c67d97d6f 172 /* Initialize state write pointer */
emh203 0:3d9c67d97d6f 173 px2 = pState;
emh203 0:3d9c67d97d6f 174
emh203 0:3d9c67d97d6f 175 /* Set accumulator to zero */
emh203 0:3d9c67d97d6f 176 acc = 0.0;
emh203 0:3d9c67d97d6f 177
emh203 0:3d9c67d97d6f 178 /* Loop unrolling. Process 4 taps at a time. */
emh203 0:3d9c67d97d6f 179 tapCnt = (numStages) >> 2;
emh203 0:3d9c67d97d6f 180
emh203 0:3d9c67d97d6f 181 while(tapCnt > 0u)
emh203 0:3d9c67d97d6f 182 {
emh203 0:3d9c67d97d6f 183 /* Read gN-1(n-1) from state buffer */
emh203 0:3d9c67d97d6f 184 gcurr1 = *px1;
emh203 0:3d9c67d97d6f 185
emh203 0:3d9c67d97d6f 186 /* read reflection coefficient kN */
emh203 0:3d9c67d97d6f 187 k1 = *pk;
emh203 0:3d9c67d97d6f 188
emh203 0:3d9c67d97d6f 189 /* fN-1(n) = fN(n) - kN * gN-1(n-1) */
emh203 0:3d9c67d97d6f 190 fnext1 = fnext2 - (k1 * gcurr1);
emh203 0:3d9c67d97d6f 191
emh203 0:3d9c67d97d6f 192 /* read ladder coefficient vN */
emh203 0:3d9c67d97d6f 193 v1 = *pv;
emh203 0:3d9c67d97d6f 194
emh203 0:3d9c67d97d6f 195 /* read next reflection coefficient kN-1 */
emh203 0:3d9c67d97d6f 196 k2 = *(pk + 1u);
emh203 0:3d9c67d97d6f 197
emh203 0:3d9c67d97d6f 198 /* Read gN-2(n-1) from state buffer */
emh203 0:3d9c67d97d6f 199 gcurr2 = *(px1 + 1u);
emh203 0:3d9c67d97d6f 200
emh203 0:3d9c67d97d6f 201 /* read next ladder coefficient vN-1 */
emh203 0:3d9c67d97d6f 202 v2 = *(pv + 1u);
emh203 0:3d9c67d97d6f 203
emh203 0:3d9c67d97d6f 204 /* fN-2(n) = fN-1(n) - kN-1 * gN-2(n-1) */
emh203 0:3d9c67d97d6f 205 fnext2 = fnext1 - (k2 * gcurr2);
emh203 0:3d9c67d97d6f 206
emh203 0:3d9c67d97d6f 207 /* gN(n) = kN * fN-1(n) + gN-1(n-1) */
emh203 0:3d9c67d97d6f 208 gnext = gcurr1 + (k1 * fnext1);
emh203 0:3d9c67d97d6f 209
emh203 0:3d9c67d97d6f 210 /* read reflection coefficient kN-2 */
emh203 0:3d9c67d97d6f 211 k1 = *(pk + 2u);
emh203 0:3d9c67d97d6f 212
emh203 0:3d9c67d97d6f 213 /* write gN(n) into state for next sample processing */
emh203 0:3d9c67d97d6f 214 *px2++ = gnext;
emh203 0:3d9c67d97d6f 215
emh203 0:3d9c67d97d6f 216 /* Read gN-3(n-1) from state buffer */
emh203 0:3d9c67d97d6f 217 gcurr1 = *(px1 + 2u);
emh203 0:3d9c67d97d6f 218
emh203 0:3d9c67d97d6f 219 /* y(n) += gN(n) * vN */
emh203 0:3d9c67d97d6f 220 acc += (gnext * v1);
emh203 0:3d9c67d97d6f 221
emh203 0:3d9c67d97d6f 222 /* fN-3(n) = fN-2(n) - kN-2 * gN-3(n-1) */
emh203 0:3d9c67d97d6f 223 fnext1 = fnext2 - (k1 * gcurr1);
emh203 0:3d9c67d97d6f 224
emh203 0:3d9c67d97d6f 225 /* gN-1(n) = kN-1 * fN-2(n) + gN-2(n-1) */
emh203 0:3d9c67d97d6f 226 gnext = gcurr2 + (k2 * fnext2);
emh203 0:3d9c67d97d6f 227
emh203 0:3d9c67d97d6f 228 /* Read gN-4(n-1) from state buffer */
emh203 0:3d9c67d97d6f 229 gcurr2 = *(px1 + 3u);
emh203 0:3d9c67d97d6f 230
emh203 0:3d9c67d97d6f 231 /* y(n) += gN-1(n) * vN-1 */
emh203 0:3d9c67d97d6f 232 acc += (gnext * v2);
emh203 0:3d9c67d97d6f 233
emh203 0:3d9c67d97d6f 234 /* read reflection coefficient kN-3 */
emh203 0:3d9c67d97d6f 235 k2 = *(pk + 3u);
emh203 0:3d9c67d97d6f 236
emh203 0:3d9c67d97d6f 237 /* write gN-1(n) into state for next sample processing */
emh203 0:3d9c67d97d6f 238 *px2++ = gnext;
emh203 0:3d9c67d97d6f 239
emh203 0:3d9c67d97d6f 240 /* fN-4(n) = fN-3(n) - kN-3 * gN-4(n-1) */
emh203 0:3d9c67d97d6f 241 fnext2 = fnext1 - (k2 * gcurr2);
emh203 0:3d9c67d97d6f 242
emh203 0:3d9c67d97d6f 243 /* gN-2(n) = kN-2 * fN-3(n) + gN-3(n-1) */
emh203 0:3d9c67d97d6f 244 gnext = gcurr1 + (k1 * fnext1);
emh203 0:3d9c67d97d6f 245
emh203 0:3d9c67d97d6f 246 /* read ladder coefficient vN-2 */
emh203 0:3d9c67d97d6f 247 v3 = *(pv + 2u);
emh203 0:3d9c67d97d6f 248
emh203 0:3d9c67d97d6f 249 /* y(n) += gN-2(n) * vN-2 */
emh203 0:3d9c67d97d6f 250 acc += (gnext * v3);
emh203 0:3d9c67d97d6f 251
emh203 0:3d9c67d97d6f 252 /* write gN-2(n) into state for next sample processing */
emh203 0:3d9c67d97d6f 253 *px2++ = gnext;
emh203 0:3d9c67d97d6f 254
emh203 0:3d9c67d97d6f 255 /* update pointer */
emh203 0:3d9c67d97d6f 256 pk += 4u;
emh203 0:3d9c67d97d6f 257
emh203 0:3d9c67d97d6f 258 /* gN-3(n) = kN-3 * fN-4(n) + gN-4(n-1) */
emh203 0:3d9c67d97d6f 259 gnext = (fnext2 * k2) + gcurr2;
emh203 0:3d9c67d97d6f 260
emh203 0:3d9c67d97d6f 261 /* read next ladder coefficient vN-3 */
emh203 0:3d9c67d97d6f 262 v4 = *(pv + 3u);
emh203 0:3d9c67d97d6f 263
emh203 0:3d9c67d97d6f 264 /* y(n) += gN-4(n) * vN-4 */
emh203 0:3d9c67d97d6f 265 acc += (gnext * v4);
emh203 0:3d9c67d97d6f 266
emh203 0:3d9c67d97d6f 267 /* write gN-3(n) into state for next sample processing */
emh203 0:3d9c67d97d6f 268 *px2++ = gnext;
emh203 0:3d9c67d97d6f 269
emh203 0:3d9c67d97d6f 270 /* update pointers */
emh203 0:3d9c67d97d6f 271 px1 += 4u;
emh203 0:3d9c67d97d6f 272 pv += 4u;
emh203 0:3d9c67d97d6f 273
emh203 0:3d9c67d97d6f 274 tapCnt--;
emh203 0:3d9c67d97d6f 275
emh203 0:3d9c67d97d6f 276 }
emh203 0:3d9c67d97d6f 277
emh203 0:3d9c67d97d6f 278 /* If the filter length is not a multiple of 4, compute the remaining filter taps */
emh203 0:3d9c67d97d6f 279 tapCnt = (numStages) % 0x4u;
emh203 0:3d9c67d97d6f 280
emh203 0:3d9c67d97d6f 281 while(tapCnt > 0u)
emh203 0:3d9c67d97d6f 282 {
emh203 0:3d9c67d97d6f 283 gcurr1 = *px1++;
emh203 0:3d9c67d97d6f 284 /* Process sample for last taps */
emh203 0:3d9c67d97d6f 285 fnext1 = fnext2 - ((*pk) * gcurr1);
emh203 0:3d9c67d97d6f 286 gnext = (fnext1 * (*pk++)) + gcurr1;
emh203 0:3d9c67d97d6f 287 /* Output samples for last taps */
emh203 0:3d9c67d97d6f 288 acc += (gnext * (*pv++));
emh203 0:3d9c67d97d6f 289 *px2++ = gnext;
emh203 0:3d9c67d97d6f 290 fnext2 = fnext1;
emh203 0:3d9c67d97d6f 291
emh203 0:3d9c67d97d6f 292 tapCnt--;
emh203 0:3d9c67d97d6f 293
emh203 0:3d9c67d97d6f 294 }
emh203 0:3d9c67d97d6f 295
emh203 0:3d9c67d97d6f 296 /* y(n) += g0(n) * v0 */
emh203 0:3d9c67d97d6f 297 acc += (fnext2 * (*pv));
emh203 0:3d9c67d97d6f 298
emh203 0:3d9c67d97d6f 299 *px2++ = fnext2;
emh203 0:3d9c67d97d6f 300
emh203 0:3d9c67d97d6f 301 /* write out into pDst */
emh203 0:3d9c67d97d6f 302 *pDst++ = acc;
emh203 0:3d9c67d97d6f 303
emh203 0:3d9c67d97d6f 304 /* Advance the state pointer by 4 to process the next group of 4 samples */
emh203 0:3d9c67d97d6f 305 pState = pState + 1u;
emh203 0:3d9c67d97d6f 306
emh203 0:3d9c67d97d6f 307 blkCnt--;
emh203 0:3d9c67d97d6f 308
emh203 0:3d9c67d97d6f 309 }
emh203 0:3d9c67d97d6f 310
emh203 0:3d9c67d97d6f 311 /* Processing is complete. Now copy last S->numStages samples to start of the buffer
emh203 0:3d9c67d97d6f 312 for the preperation of next frame process */
emh203 0:3d9c67d97d6f 313
emh203 0:3d9c67d97d6f 314 /* Points to the start of the state buffer */
emh203 0:3d9c67d97d6f 315 pStateCurnt = &S->pState[0];
emh203 0:3d9c67d97d6f 316 pState = &S->pState[blockSize];
emh203 0:3d9c67d97d6f 317
emh203 0:3d9c67d97d6f 318 tapCnt = numStages >> 2u;
emh203 0:3d9c67d97d6f 319
emh203 0:3d9c67d97d6f 320 /* copy data */
emh203 0:3d9c67d97d6f 321 while(tapCnt > 0u)
emh203 0:3d9c67d97d6f 322 {
emh203 0:3d9c67d97d6f 323 *pStateCurnt++ = *pState++;
emh203 0:3d9c67d97d6f 324 *pStateCurnt++ = *pState++;
emh203 0:3d9c67d97d6f 325 *pStateCurnt++ = *pState++;
emh203 0:3d9c67d97d6f 326 *pStateCurnt++ = *pState++;
emh203 0:3d9c67d97d6f 327
emh203 0:3d9c67d97d6f 328 /* Decrement the loop counter */
emh203 0:3d9c67d97d6f 329 tapCnt--;
emh203 0:3d9c67d97d6f 330
emh203 0:3d9c67d97d6f 331 }
emh203 0:3d9c67d97d6f 332
emh203 0:3d9c67d97d6f 333 /* Calculate remaining number of copies */
emh203 0:3d9c67d97d6f 334 tapCnt = (numStages) % 0x4u;
emh203 0:3d9c67d97d6f 335
emh203 0:3d9c67d97d6f 336 /* Copy the remaining q31_t data */
emh203 0:3d9c67d97d6f 337 while(tapCnt > 0u)
emh203 0:3d9c67d97d6f 338 {
emh203 0:3d9c67d97d6f 339 *pStateCurnt++ = *pState++;
emh203 0:3d9c67d97d6f 340
emh203 0:3d9c67d97d6f 341 /* Decrement the loop counter */
emh203 0:3d9c67d97d6f 342 tapCnt--;
emh203 0:3d9c67d97d6f 343 }
emh203 0:3d9c67d97d6f 344 }
emh203 0:3d9c67d97d6f 345
emh203 0:3d9c67d97d6f 346 #else
emh203 0:3d9c67d97d6f 347
emh203 0:3d9c67d97d6f 348 void arm_iir_lattice_f32(
emh203 0:3d9c67d97d6f 349 const arm_iir_lattice_instance_f32 * S,
emh203 0:3d9c67d97d6f 350 float32_t * pSrc,
emh203 0:3d9c67d97d6f 351 float32_t * pDst,
emh203 0:3d9c67d97d6f 352 uint32_t blockSize)
emh203 0:3d9c67d97d6f 353 {
emh203 0:3d9c67d97d6f 354 float32_t fcurr, fnext = 0, gcurr, gnext; /* Temporary variables for lattice stages */
emh203 0:3d9c67d97d6f 355 float32_t acc; /* Accumlator */
emh203 0:3d9c67d97d6f 356 uint32_t blkCnt, tapCnt; /* temporary variables for counts */
emh203 0:3d9c67d97d6f 357 float32_t *px1, *px2, *pk, *pv; /* temporary pointers for state and coef */
emh203 0:3d9c67d97d6f 358 uint32_t numStages = S->numStages; /* number of stages */
emh203 0:3d9c67d97d6f 359 float32_t *pState; /* State pointer */
emh203 0:3d9c67d97d6f 360 float32_t *pStateCurnt; /* State current pointer */
emh203 0:3d9c67d97d6f 361
emh203 0:3d9c67d97d6f 362
emh203 0:3d9c67d97d6f 363 /* Run the below code for Cortex-M0 */
emh203 0:3d9c67d97d6f 364
emh203 0:3d9c67d97d6f 365 blkCnt = blockSize;
emh203 0:3d9c67d97d6f 366
emh203 0:3d9c67d97d6f 367 pState = &S->pState[0];
emh203 0:3d9c67d97d6f 368
emh203 0:3d9c67d97d6f 369 /* Sample processing */
emh203 0:3d9c67d97d6f 370 while(blkCnt > 0u)
emh203 0:3d9c67d97d6f 371 {
emh203 0:3d9c67d97d6f 372 /* Read Sample from input buffer */
emh203 0:3d9c67d97d6f 373 /* fN(n) = x(n) */
emh203 0:3d9c67d97d6f 374 fcurr = *pSrc++;
emh203 0:3d9c67d97d6f 375
emh203 0:3d9c67d97d6f 376 /* Initialize state read pointer */
emh203 0:3d9c67d97d6f 377 px1 = pState;
emh203 0:3d9c67d97d6f 378 /* Initialize state write pointer */
emh203 0:3d9c67d97d6f 379 px2 = pState;
emh203 0:3d9c67d97d6f 380 /* Set accumulator to zero */
emh203 0:3d9c67d97d6f 381 acc = 0.0f;
emh203 0:3d9c67d97d6f 382 /* Initialize Ladder coeff pointer */
emh203 0:3d9c67d97d6f 383 pv = &S->pvCoeffs[0];
emh203 0:3d9c67d97d6f 384 /* Initialize Reflection coeff pointer */
emh203 0:3d9c67d97d6f 385 pk = &S->pkCoeffs[0];
emh203 0:3d9c67d97d6f 386
emh203 0:3d9c67d97d6f 387
emh203 0:3d9c67d97d6f 388 /* Process sample for numStages */
emh203 0:3d9c67d97d6f 389 tapCnt = numStages;
emh203 0:3d9c67d97d6f 390
emh203 0:3d9c67d97d6f 391 while(tapCnt > 0u)
emh203 0:3d9c67d97d6f 392 {
emh203 0:3d9c67d97d6f 393 gcurr = *px1++;
emh203 0:3d9c67d97d6f 394 /* Process sample for last taps */
emh203 0:3d9c67d97d6f 395 fnext = fcurr - ((*pk) * gcurr);
emh203 0:3d9c67d97d6f 396 gnext = (fnext * (*pk++)) + gcurr;
emh203 0:3d9c67d97d6f 397
emh203 0:3d9c67d97d6f 398 /* Output samples for last taps */
emh203 0:3d9c67d97d6f 399 acc += (gnext * (*pv++));
emh203 0:3d9c67d97d6f 400 *px2++ = gnext;
emh203 0:3d9c67d97d6f 401 fcurr = fnext;
emh203 0:3d9c67d97d6f 402
emh203 0:3d9c67d97d6f 403 /* Decrementing loop counter */
emh203 0:3d9c67d97d6f 404 tapCnt--;
emh203 0:3d9c67d97d6f 405
emh203 0:3d9c67d97d6f 406 }
emh203 0:3d9c67d97d6f 407
emh203 0:3d9c67d97d6f 408 /* y(n) += g0(n) * v0 */
emh203 0:3d9c67d97d6f 409 acc += (fnext * (*pv));
emh203 0:3d9c67d97d6f 410
emh203 0:3d9c67d97d6f 411 *px2++ = fnext;
emh203 0:3d9c67d97d6f 412
emh203 0:3d9c67d97d6f 413 /* write out into pDst */
emh203 0:3d9c67d97d6f 414 *pDst++ = acc;
emh203 0:3d9c67d97d6f 415
emh203 0:3d9c67d97d6f 416 /* Advance the state pointer by 1 to process the next group of samples */
emh203 0:3d9c67d97d6f 417 pState = pState + 1u;
emh203 0:3d9c67d97d6f 418 blkCnt--;
emh203 0:3d9c67d97d6f 419
emh203 0:3d9c67d97d6f 420 }
emh203 0:3d9c67d97d6f 421
emh203 0:3d9c67d97d6f 422 /* Processing is complete. Now copy last S->numStages samples to start of the buffer
emh203 0:3d9c67d97d6f 423 for the preperation of next frame process */
emh203 0:3d9c67d97d6f 424
emh203 0:3d9c67d97d6f 425 /* Points to the start of the state buffer */
emh203 0:3d9c67d97d6f 426 pStateCurnt = &S->pState[0];
emh203 0:3d9c67d97d6f 427 pState = &S->pState[blockSize];
emh203 0:3d9c67d97d6f 428
emh203 0:3d9c67d97d6f 429 tapCnt = numStages;
emh203 0:3d9c67d97d6f 430
emh203 0:3d9c67d97d6f 431 /* Copy the data */
emh203 0:3d9c67d97d6f 432 while(tapCnt > 0u)
emh203 0:3d9c67d97d6f 433 {
emh203 0:3d9c67d97d6f 434 *pStateCurnt++ = *pState++;
emh203 0:3d9c67d97d6f 435
emh203 0:3d9c67d97d6f 436 /* Decrement the loop counter */
emh203 0:3d9c67d97d6f 437 tapCnt--;
emh203 0:3d9c67d97d6f 438 }
emh203 0:3d9c67d97d6f 439
emh203 0:3d9c67d97d6f 440 }
emh203 0:3d9c67d97d6f 441
emh203 0:3d9c67d97d6f 442 #endif /* #ifndef ARM_MATH_CM0_FAMILY */
emh203 0:3d9c67d97d6f 443
emh203 0:3d9c67d97d6f 444
emh203 0:3d9c67d97d6f 445 /**
emh203 0:3d9c67d97d6f 446 * @} end of IIR_Lattice group
emh203 0:3d9c67d97d6f 447 */