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_biquad_cascade_df1_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_biquad_cascade_df1_q31.c
emh203 0:3d9c67d97d6f 9 *
emh203 0:3d9c67d97d6f 10 * Description: Processing function for the
emh203 0:3d9c67d97d6f 11 * Q31 Biquad cascade filter
emh203 0:3d9c67d97d6f 12 *
emh203 0:3d9c67d97d6f 13 * Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
emh203 0:3d9c67d97d6f 14 *
emh203 0:3d9c67d97d6f 15 * Redistribution and use in source and binary forms, with or without
emh203 0:3d9c67d97d6f 16 * modification, are permitted provided that the following conditions
emh203 0:3d9c67d97d6f 17 * are met:
emh203 0:3d9c67d97d6f 18 * - Redistributions of source code must retain the above copyright
emh203 0:3d9c67d97d6f 19 * notice, this list of conditions and the following disclaimer.
emh203 0:3d9c67d97d6f 20 * - Redistributions in binary form must reproduce the above copyright
emh203 0:3d9c67d97d6f 21 * notice, this list of conditions and the following disclaimer in
emh203 0:3d9c67d97d6f 22 * the documentation and/or other materials provided with the
emh203 0:3d9c67d97d6f 23 * distribution.
emh203 0:3d9c67d97d6f 24 * - Neither the name of ARM LIMITED nor the names of its contributors
emh203 0:3d9c67d97d6f 25 * may be used to endorse or promote products derived from this
emh203 0:3d9c67d97d6f 26 * software without specific prior written permission.
emh203 0:3d9c67d97d6f 27 *
emh203 0:3d9c67d97d6f 28 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
emh203 0:3d9c67d97d6f 29 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
emh203 0:3d9c67d97d6f 30 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
emh203 0:3d9c67d97d6f 31 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
emh203 0:3d9c67d97d6f 32 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
emh203 0:3d9c67d97d6f 33 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
emh203 0:3d9c67d97d6f 34 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
emh203 0:3d9c67d97d6f 35 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
emh203 0:3d9c67d97d6f 36 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
emh203 0:3d9c67d97d6f 37 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
emh203 0:3d9c67d97d6f 38 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
emh203 0:3d9c67d97d6f 39 * POSSIBILITY OF SUCH DAMAGE.
emh203 0:3d9c67d97d6f 40 * -------------------------------------------------------------------- */
emh203 0:3d9c67d97d6f 41
emh203 0:3d9c67d97d6f 42 #include "arm_math.h"
emh203 0:3d9c67d97d6f 43
emh203 0:3d9c67d97d6f 44 /**
emh203 0:3d9c67d97d6f 45 * @ingroup groupFilters
emh203 0:3d9c67d97d6f 46 */
emh203 0:3d9c67d97d6f 47
emh203 0:3d9c67d97d6f 48 /**
emh203 0:3d9c67d97d6f 49 * @addtogroup BiquadCascadeDF1
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 Biquad cascade filter.
emh203 0:3d9c67d97d6f 55 * @param[in] *S points to an instance of the Q31 Biquad cascade 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 per call.
emh203 0:3d9c67d97d6f 59 * @return none.
emh203 0:3d9c67d97d6f 60 *
emh203 0:3d9c67d97d6f 61 * <b>Scaling and Overflow Behavior:</b>
emh203 0:3d9c67d97d6f 62 * \par
emh203 0:3d9c67d97d6f 63 * The function is implemented using an internal 64-bit accumulator.
emh203 0:3d9c67d97d6f 64 * 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 65 * Thus, if the accumulator result overflows it wraps around rather than clip.
emh203 0:3d9c67d97d6f 66 * In order to avoid overflows completely the input signal must be scaled down by 2 bits and lie in the range [-0.25 +0.25).
emh203 0:3d9c67d97d6f 67 * After all 5 multiply-accumulates are performed, the 2.62 accumulator is shifted by <code>postShift</code> bits and the result truncated to
emh203 0:3d9c67d97d6f 68 * 1.31 format by discarding the low 32 bits.
emh203 0:3d9c67d97d6f 69 *
emh203 0:3d9c67d97d6f 70 * \par
emh203 0:3d9c67d97d6f 71 * Refer to the function <code>arm_biquad_cascade_df1_fast_q31()</code> for a faster but less precise implementation of this filter for Cortex-M3 and Cortex-M4.
emh203 0:3d9c67d97d6f 72 */
emh203 0:3d9c67d97d6f 73
emh203 0:3d9c67d97d6f 74 void arm_biquad_cascade_df1_q31(
emh203 0:3d9c67d97d6f 75 const arm_biquad_casd_df1_inst_q31 * S,
emh203 0:3d9c67d97d6f 76 q31_t * pSrc,
emh203 0:3d9c67d97d6f 77 q31_t * pDst,
emh203 0:3d9c67d97d6f 78 uint32_t blockSize)
emh203 0:3d9c67d97d6f 79 {
emh203 0:3d9c67d97d6f 80 q63_t acc; /* accumulator */
emh203 0:3d9c67d97d6f 81 uint32_t uShift = ((uint32_t) S->postShift + 1u);
emh203 0:3d9c67d97d6f 82 uint32_t lShift = 32u - uShift; /* Shift to be applied to the output */
emh203 0:3d9c67d97d6f 83 q31_t *pIn = pSrc; /* input pointer initialization */
emh203 0:3d9c67d97d6f 84 q31_t *pOut = pDst; /* output pointer initialization */
emh203 0:3d9c67d97d6f 85 q31_t *pState = S->pState; /* pState pointer initialization */
emh203 0:3d9c67d97d6f 86 q31_t *pCoeffs = S->pCoeffs; /* coeff pointer initialization */
emh203 0:3d9c67d97d6f 87 q31_t Xn1, Xn2, Yn1, Yn2; /* Filter state variables */
emh203 0:3d9c67d97d6f 88 q31_t b0, b1, b2, a1, a2; /* Filter coefficients */
emh203 0:3d9c67d97d6f 89 q31_t Xn; /* temporary input */
emh203 0:3d9c67d97d6f 90 uint32_t sample, stage = S->numStages; /* loop counters */
emh203 0:3d9c67d97d6f 91
emh203 0:3d9c67d97d6f 92
emh203 0:3d9c67d97d6f 93 #ifndef ARM_MATH_CM0_FAMILY_FAMILY
emh203 0:3d9c67d97d6f 94
emh203 0:3d9c67d97d6f 95 q31_t acc_l, acc_h; /* temporary output variables */
emh203 0:3d9c67d97d6f 96
emh203 0:3d9c67d97d6f 97 /* Run the below code for Cortex-M4 and Cortex-M3 */
emh203 0:3d9c67d97d6f 98
emh203 0:3d9c67d97d6f 99 do
emh203 0:3d9c67d97d6f 100 {
emh203 0:3d9c67d97d6f 101 /* Reading the coefficients */
emh203 0:3d9c67d97d6f 102 b0 = *pCoeffs++;
emh203 0:3d9c67d97d6f 103 b1 = *pCoeffs++;
emh203 0:3d9c67d97d6f 104 b2 = *pCoeffs++;
emh203 0:3d9c67d97d6f 105 a1 = *pCoeffs++;
emh203 0:3d9c67d97d6f 106 a2 = *pCoeffs++;
emh203 0:3d9c67d97d6f 107
emh203 0:3d9c67d97d6f 108 /* Reading the state values */
emh203 0:3d9c67d97d6f 109 Xn1 = pState[0];
emh203 0:3d9c67d97d6f 110 Xn2 = pState[1];
emh203 0:3d9c67d97d6f 111 Yn1 = pState[2];
emh203 0:3d9c67d97d6f 112 Yn2 = pState[3];
emh203 0:3d9c67d97d6f 113
emh203 0:3d9c67d97d6f 114 /* Apply loop unrolling and compute 4 output values simultaneously. */
emh203 0:3d9c67d97d6f 115 /* The variable acc hold output values that are being computed:
emh203 0:3d9c67d97d6f 116 *
emh203 0:3d9c67d97d6f 117 * acc = b0 * x[n] + b1 * x[n-1] + b2 * x[n-2] + a1 * y[n-1] + a2 * y[n-2]
emh203 0:3d9c67d97d6f 118 */
emh203 0:3d9c67d97d6f 119
emh203 0:3d9c67d97d6f 120 sample = blockSize >> 2u;
emh203 0:3d9c67d97d6f 121
emh203 0:3d9c67d97d6f 122 /* First part of the processing with loop unrolling. Compute 4 outputs at a time.
emh203 0:3d9c67d97d6f 123 ** a second loop below computes the remaining 1 to 3 samples. */
emh203 0:3d9c67d97d6f 124 while(sample > 0u)
emh203 0:3d9c67d97d6f 125 {
emh203 0:3d9c67d97d6f 126 /* Read the input */
emh203 0:3d9c67d97d6f 127 Xn = *pIn++;
emh203 0:3d9c67d97d6f 128
emh203 0:3d9c67d97d6f 129 /* acc = b0 * x[n] + b1 * x[n-1] + b2 * x[n-2] + a1 * y[n-1] + a2 * y[n-2] */
emh203 0:3d9c67d97d6f 130
emh203 0:3d9c67d97d6f 131 /* acc = b0 * x[n] */
emh203 0:3d9c67d97d6f 132 acc = (q63_t) b0 *Xn;
emh203 0:3d9c67d97d6f 133 /* acc += b1 * x[n-1] */
emh203 0:3d9c67d97d6f 134 acc += (q63_t) b1 *Xn1;
emh203 0:3d9c67d97d6f 135 /* acc += b[2] * x[n-2] */
emh203 0:3d9c67d97d6f 136 acc += (q63_t) b2 *Xn2;
emh203 0:3d9c67d97d6f 137 /* acc += a1 * y[n-1] */
emh203 0:3d9c67d97d6f 138 acc += (q63_t) a1 *Yn1;
emh203 0:3d9c67d97d6f 139 /* acc += a2 * y[n-2] */
emh203 0:3d9c67d97d6f 140 acc += (q63_t) a2 *Yn2;
emh203 0:3d9c67d97d6f 141
emh203 0:3d9c67d97d6f 142 /* The result is converted to 1.31 , Yn2 variable is reused */
emh203 0:3d9c67d97d6f 143
emh203 0:3d9c67d97d6f 144 /* Calc lower part of acc */
emh203 0:3d9c67d97d6f 145 acc_l = acc & 0xffffffff;
emh203 0:3d9c67d97d6f 146
emh203 0:3d9c67d97d6f 147 /* Calc upper part of acc */
emh203 0:3d9c67d97d6f 148 acc_h = (acc >> 32) & 0xffffffff;
emh203 0:3d9c67d97d6f 149
emh203 0:3d9c67d97d6f 150 /* Apply shift for lower part of acc and upper part of acc */
emh203 0:3d9c67d97d6f 151 Yn2 = (uint32_t) acc_l >> lShift | acc_h << uShift;
emh203 0:3d9c67d97d6f 152
emh203 0:3d9c67d97d6f 153 /* Store the output in the destination buffer. */
emh203 0:3d9c67d97d6f 154 *pOut++ = Yn2;
emh203 0:3d9c67d97d6f 155
emh203 0:3d9c67d97d6f 156 /* Read the second input */
emh203 0:3d9c67d97d6f 157 Xn2 = *pIn++;
emh203 0:3d9c67d97d6f 158
emh203 0:3d9c67d97d6f 159 /* acc = b0 * x[n] + b1 * x[n-1] + b2 * x[n-2] + a1 * y[n-1] + a2 * y[n-2] */
emh203 0:3d9c67d97d6f 160
emh203 0:3d9c67d97d6f 161 /* acc = b0 * x[n] */
emh203 0:3d9c67d97d6f 162 acc = (q63_t) b0 *Xn2;
emh203 0:3d9c67d97d6f 163 /* acc += b1 * x[n-1] */
emh203 0:3d9c67d97d6f 164 acc += (q63_t) b1 *Xn;
emh203 0:3d9c67d97d6f 165 /* acc += b[2] * x[n-2] */
emh203 0:3d9c67d97d6f 166 acc += (q63_t) b2 *Xn1;
emh203 0:3d9c67d97d6f 167 /* acc += a1 * y[n-1] */
emh203 0:3d9c67d97d6f 168 acc += (q63_t) a1 *Yn2;
emh203 0:3d9c67d97d6f 169 /* acc += a2 * y[n-2] */
emh203 0:3d9c67d97d6f 170 acc += (q63_t) a2 *Yn1;
emh203 0:3d9c67d97d6f 171
emh203 0:3d9c67d97d6f 172
emh203 0:3d9c67d97d6f 173 /* The result is converted to 1.31, Yn1 variable is reused */
emh203 0:3d9c67d97d6f 174
emh203 0:3d9c67d97d6f 175 /* Calc lower part of acc */
emh203 0:3d9c67d97d6f 176 acc_l = acc & 0xffffffff;
emh203 0:3d9c67d97d6f 177
emh203 0:3d9c67d97d6f 178 /* Calc upper part of acc */
emh203 0:3d9c67d97d6f 179 acc_h = (acc >> 32) & 0xffffffff;
emh203 0:3d9c67d97d6f 180
emh203 0:3d9c67d97d6f 181
emh203 0:3d9c67d97d6f 182 /* Apply shift for lower part of acc and upper part of acc */
emh203 0:3d9c67d97d6f 183 Yn1 = (uint32_t) acc_l >> lShift | acc_h << uShift;
emh203 0:3d9c67d97d6f 184
emh203 0:3d9c67d97d6f 185 /* Store the output in the destination buffer. */
emh203 0:3d9c67d97d6f 186 *pOut++ = Yn1;
emh203 0:3d9c67d97d6f 187
emh203 0:3d9c67d97d6f 188 /* Read the third input */
emh203 0:3d9c67d97d6f 189 Xn1 = *pIn++;
emh203 0:3d9c67d97d6f 190
emh203 0:3d9c67d97d6f 191 /* acc = b0 * x[n] + b1 * x[n-1] + b2 * x[n-2] + a1 * y[n-1] + a2 * y[n-2] */
emh203 0:3d9c67d97d6f 192
emh203 0:3d9c67d97d6f 193 /* acc = b0 * x[n] */
emh203 0:3d9c67d97d6f 194 acc = (q63_t) b0 *Xn1;
emh203 0:3d9c67d97d6f 195 /* acc += b1 * x[n-1] */
emh203 0:3d9c67d97d6f 196 acc += (q63_t) b1 *Xn2;
emh203 0:3d9c67d97d6f 197 /* acc += b[2] * x[n-2] */
emh203 0:3d9c67d97d6f 198 acc += (q63_t) b2 *Xn;
emh203 0:3d9c67d97d6f 199 /* acc += a1 * y[n-1] */
emh203 0:3d9c67d97d6f 200 acc += (q63_t) a1 *Yn1;
emh203 0:3d9c67d97d6f 201 /* acc += a2 * y[n-2] */
emh203 0:3d9c67d97d6f 202 acc += (q63_t) a2 *Yn2;
emh203 0:3d9c67d97d6f 203
emh203 0:3d9c67d97d6f 204 /* The result is converted to 1.31, Yn2 variable is reused */
emh203 0:3d9c67d97d6f 205 /* Calc lower part of acc */
emh203 0:3d9c67d97d6f 206 acc_l = acc & 0xffffffff;
emh203 0:3d9c67d97d6f 207
emh203 0:3d9c67d97d6f 208 /* Calc upper part of acc */
emh203 0:3d9c67d97d6f 209 acc_h = (acc >> 32) & 0xffffffff;
emh203 0:3d9c67d97d6f 210
emh203 0:3d9c67d97d6f 211
emh203 0:3d9c67d97d6f 212 /* Apply shift for lower part of acc and upper part of acc */
emh203 0:3d9c67d97d6f 213 Yn2 = (uint32_t) acc_l >> lShift | acc_h << uShift;
emh203 0:3d9c67d97d6f 214
emh203 0:3d9c67d97d6f 215 /* Store the output in the destination buffer. */
emh203 0:3d9c67d97d6f 216 *pOut++ = Yn2;
emh203 0:3d9c67d97d6f 217
emh203 0:3d9c67d97d6f 218 /* Read the forth input */
emh203 0:3d9c67d97d6f 219 Xn = *pIn++;
emh203 0:3d9c67d97d6f 220
emh203 0:3d9c67d97d6f 221 /* acc = b0 * x[n] + b1 * x[n-1] + b2 * x[n-2] + a1 * y[n-1] + a2 * y[n-2] */
emh203 0:3d9c67d97d6f 222
emh203 0:3d9c67d97d6f 223 /* acc = b0 * x[n] */
emh203 0:3d9c67d97d6f 224 acc = (q63_t) b0 *Xn;
emh203 0:3d9c67d97d6f 225 /* acc += b1 * x[n-1] */
emh203 0:3d9c67d97d6f 226 acc += (q63_t) b1 *Xn1;
emh203 0:3d9c67d97d6f 227 /* acc += b[2] * x[n-2] */
emh203 0:3d9c67d97d6f 228 acc += (q63_t) b2 *Xn2;
emh203 0:3d9c67d97d6f 229 /* acc += a1 * y[n-1] */
emh203 0:3d9c67d97d6f 230 acc += (q63_t) a1 *Yn2;
emh203 0:3d9c67d97d6f 231 /* acc += a2 * y[n-2] */
emh203 0:3d9c67d97d6f 232 acc += (q63_t) a2 *Yn1;
emh203 0:3d9c67d97d6f 233
emh203 0:3d9c67d97d6f 234 /* The result is converted to 1.31, Yn1 variable is reused */
emh203 0:3d9c67d97d6f 235 /* Calc lower part of acc */
emh203 0:3d9c67d97d6f 236 acc_l = acc & 0xffffffff;
emh203 0:3d9c67d97d6f 237
emh203 0:3d9c67d97d6f 238 /* Calc upper part of acc */
emh203 0:3d9c67d97d6f 239 acc_h = (acc >> 32) & 0xffffffff;
emh203 0:3d9c67d97d6f 240
emh203 0:3d9c67d97d6f 241 /* Apply shift for lower part of acc and upper part of acc */
emh203 0:3d9c67d97d6f 242 Yn1 = (uint32_t) acc_l >> lShift | acc_h << uShift;
emh203 0:3d9c67d97d6f 243
emh203 0:3d9c67d97d6f 244 /* Every time after the output is computed state should be updated. */
emh203 0:3d9c67d97d6f 245 /* The states should be updated as: */
emh203 0:3d9c67d97d6f 246 /* Xn2 = Xn1 */
emh203 0:3d9c67d97d6f 247 /* Xn1 = Xn */
emh203 0:3d9c67d97d6f 248 /* Yn2 = Yn1 */
emh203 0:3d9c67d97d6f 249 /* Yn1 = acc */
emh203 0:3d9c67d97d6f 250 Xn2 = Xn1;
emh203 0:3d9c67d97d6f 251 Xn1 = Xn;
emh203 0:3d9c67d97d6f 252
emh203 0:3d9c67d97d6f 253 /* Store the output in the destination buffer. */
emh203 0:3d9c67d97d6f 254 *pOut++ = Yn1;
emh203 0:3d9c67d97d6f 255
emh203 0:3d9c67d97d6f 256 /* decrement the loop counter */
emh203 0:3d9c67d97d6f 257 sample--;
emh203 0:3d9c67d97d6f 258 }
emh203 0:3d9c67d97d6f 259
emh203 0:3d9c67d97d6f 260 /* If the blockSize is not a multiple of 4, compute any remaining output samples here.
emh203 0:3d9c67d97d6f 261 ** No loop unrolling is used. */
emh203 0:3d9c67d97d6f 262 sample = (blockSize & 0x3u);
emh203 0:3d9c67d97d6f 263
emh203 0:3d9c67d97d6f 264 while(sample > 0u)
emh203 0:3d9c67d97d6f 265 {
emh203 0:3d9c67d97d6f 266 /* Read the input */
emh203 0:3d9c67d97d6f 267 Xn = *pIn++;
emh203 0:3d9c67d97d6f 268
emh203 0:3d9c67d97d6f 269 /* acc = b0 * x[n] + b1 * x[n-1] + b2 * x[n-2] + a1 * y[n-1] + a2 * y[n-2] */
emh203 0:3d9c67d97d6f 270
emh203 0:3d9c67d97d6f 271 /* acc = b0 * x[n] */
emh203 0:3d9c67d97d6f 272 acc = (q63_t) b0 *Xn;
emh203 0:3d9c67d97d6f 273 /* acc += b1 * x[n-1] */
emh203 0:3d9c67d97d6f 274 acc += (q63_t) b1 *Xn1;
emh203 0:3d9c67d97d6f 275 /* acc += b[2] * x[n-2] */
emh203 0:3d9c67d97d6f 276 acc += (q63_t) b2 *Xn2;
emh203 0:3d9c67d97d6f 277 /* acc += a1 * y[n-1] */
emh203 0:3d9c67d97d6f 278 acc += (q63_t) a1 *Yn1;
emh203 0:3d9c67d97d6f 279 /* acc += a2 * y[n-2] */
emh203 0:3d9c67d97d6f 280 acc += (q63_t) a2 *Yn2;
emh203 0:3d9c67d97d6f 281
emh203 0:3d9c67d97d6f 282 /* The result is converted to 1.31 */
emh203 0:3d9c67d97d6f 283 acc = acc >> lShift;
emh203 0:3d9c67d97d6f 284
emh203 0:3d9c67d97d6f 285 /* Every time after the output is computed state should be updated. */
emh203 0:3d9c67d97d6f 286 /* The states should be updated as: */
emh203 0:3d9c67d97d6f 287 /* Xn2 = Xn1 */
emh203 0:3d9c67d97d6f 288 /* Xn1 = Xn */
emh203 0:3d9c67d97d6f 289 /* Yn2 = Yn1 */
emh203 0:3d9c67d97d6f 290 /* Yn1 = acc */
emh203 0:3d9c67d97d6f 291 Xn2 = Xn1;
emh203 0:3d9c67d97d6f 292 Xn1 = Xn;
emh203 0:3d9c67d97d6f 293 Yn2 = Yn1;
emh203 0:3d9c67d97d6f 294 Yn1 = (q31_t) acc;
emh203 0:3d9c67d97d6f 295
emh203 0:3d9c67d97d6f 296 /* Store the output in the destination buffer. */
emh203 0:3d9c67d97d6f 297 *pOut++ = (q31_t) acc;
emh203 0:3d9c67d97d6f 298
emh203 0:3d9c67d97d6f 299 /* decrement the loop counter */
emh203 0:3d9c67d97d6f 300 sample--;
emh203 0:3d9c67d97d6f 301 }
emh203 0:3d9c67d97d6f 302
emh203 0:3d9c67d97d6f 303 /* The first stage goes from the input buffer to the output buffer. */
emh203 0:3d9c67d97d6f 304 /* Subsequent stages occur in-place in the output buffer */
emh203 0:3d9c67d97d6f 305 pIn = pDst;
emh203 0:3d9c67d97d6f 306
emh203 0:3d9c67d97d6f 307 /* Reset to destination pointer */
emh203 0:3d9c67d97d6f 308 pOut = pDst;
emh203 0:3d9c67d97d6f 309
emh203 0:3d9c67d97d6f 310 /* Store the updated state variables back into the pState array */
emh203 0:3d9c67d97d6f 311 *pState++ = Xn1;
emh203 0:3d9c67d97d6f 312 *pState++ = Xn2;
emh203 0:3d9c67d97d6f 313 *pState++ = Yn1;
emh203 0:3d9c67d97d6f 314 *pState++ = Yn2;
emh203 0:3d9c67d97d6f 315
emh203 0:3d9c67d97d6f 316 } while(--stage);
emh203 0:3d9c67d97d6f 317
emh203 0:3d9c67d97d6f 318 #else
emh203 0:3d9c67d97d6f 319
emh203 0:3d9c67d97d6f 320 /* Run the below code for Cortex-M0 */
emh203 0:3d9c67d97d6f 321
emh203 0:3d9c67d97d6f 322 do
emh203 0:3d9c67d97d6f 323 {
emh203 0:3d9c67d97d6f 324 /* Reading the coefficients */
emh203 0:3d9c67d97d6f 325 b0 = *pCoeffs++;
emh203 0:3d9c67d97d6f 326 b1 = *pCoeffs++;
emh203 0:3d9c67d97d6f 327 b2 = *pCoeffs++;
emh203 0:3d9c67d97d6f 328 a1 = *pCoeffs++;
emh203 0:3d9c67d97d6f 329 a2 = *pCoeffs++;
emh203 0:3d9c67d97d6f 330
emh203 0:3d9c67d97d6f 331 /* Reading the state values */
emh203 0:3d9c67d97d6f 332 Xn1 = pState[0];
emh203 0:3d9c67d97d6f 333 Xn2 = pState[1];
emh203 0:3d9c67d97d6f 334 Yn1 = pState[2];
emh203 0:3d9c67d97d6f 335 Yn2 = pState[3];
emh203 0:3d9c67d97d6f 336
emh203 0:3d9c67d97d6f 337 /* The variables acc holds the output value that is computed:
emh203 0:3d9c67d97d6f 338 * acc = b0 * x[n] + b1 * x[n-1] + b2 * x[n-2] + a1 * y[n-1] + a2 * y[n-2]
emh203 0:3d9c67d97d6f 339 */
emh203 0:3d9c67d97d6f 340
emh203 0:3d9c67d97d6f 341 sample = blockSize;
emh203 0:3d9c67d97d6f 342
emh203 0:3d9c67d97d6f 343 while(sample > 0u)
emh203 0:3d9c67d97d6f 344 {
emh203 0:3d9c67d97d6f 345 /* Read the input */
emh203 0:3d9c67d97d6f 346 Xn = *pIn++;
emh203 0:3d9c67d97d6f 347
emh203 0:3d9c67d97d6f 348 /* acc = b0 * x[n] + b1 * x[n-1] + b2 * x[n-2] + a1 * y[n-1] + a2 * y[n-2] */
emh203 0:3d9c67d97d6f 349 /* acc = b0 * x[n] */
emh203 0:3d9c67d97d6f 350 acc = (q63_t) b0 *Xn;
emh203 0:3d9c67d97d6f 351
emh203 0:3d9c67d97d6f 352 /* acc += b1 * x[n-1] */
emh203 0:3d9c67d97d6f 353 acc += (q63_t) b1 *Xn1;
emh203 0:3d9c67d97d6f 354 /* acc += b[2] * x[n-2] */
emh203 0:3d9c67d97d6f 355 acc += (q63_t) b2 *Xn2;
emh203 0:3d9c67d97d6f 356 /* acc += a1 * y[n-1] */
emh203 0:3d9c67d97d6f 357 acc += (q63_t) a1 *Yn1;
emh203 0:3d9c67d97d6f 358 /* acc += a2 * y[n-2] */
emh203 0:3d9c67d97d6f 359 acc += (q63_t) a2 *Yn2;
emh203 0:3d9c67d97d6f 360
emh203 0:3d9c67d97d6f 361 /* The result is converted to 1.31 */
emh203 0:3d9c67d97d6f 362 acc = acc >> lShift;
emh203 0:3d9c67d97d6f 363
emh203 0:3d9c67d97d6f 364 /* Every time after the output is computed state should be updated. */
emh203 0:3d9c67d97d6f 365 /* The states should be updated as: */
emh203 0:3d9c67d97d6f 366 /* Xn2 = Xn1 */
emh203 0:3d9c67d97d6f 367 /* Xn1 = Xn */
emh203 0:3d9c67d97d6f 368 /* Yn2 = Yn1 */
emh203 0:3d9c67d97d6f 369 /* Yn1 = acc */
emh203 0:3d9c67d97d6f 370 Xn2 = Xn1;
emh203 0:3d9c67d97d6f 371 Xn1 = Xn;
emh203 0:3d9c67d97d6f 372 Yn2 = Yn1;
emh203 0:3d9c67d97d6f 373 Yn1 = (q31_t) acc;
emh203 0:3d9c67d97d6f 374
emh203 0:3d9c67d97d6f 375 /* Store the output in the destination buffer. */
emh203 0:3d9c67d97d6f 376 *pOut++ = (q31_t) acc;
emh203 0:3d9c67d97d6f 377
emh203 0:3d9c67d97d6f 378 /* decrement the loop counter */
emh203 0:3d9c67d97d6f 379 sample--;
emh203 0:3d9c67d97d6f 380 }
emh203 0:3d9c67d97d6f 381
emh203 0:3d9c67d97d6f 382 /* The first stage goes from the input buffer to the output buffer. */
emh203 0:3d9c67d97d6f 383 /* Subsequent stages occur in-place in the output buffer */
emh203 0:3d9c67d97d6f 384 pIn = pDst;
emh203 0:3d9c67d97d6f 385
emh203 0:3d9c67d97d6f 386 /* Reset to destination pointer */
emh203 0:3d9c67d97d6f 387 pOut = pDst;
emh203 0:3d9c67d97d6f 388
emh203 0:3d9c67d97d6f 389 /* Store the updated state variables back into the pState array */
emh203 0:3d9c67d97d6f 390 *pState++ = Xn1;
emh203 0:3d9c67d97d6f 391 *pState++ = Xn2;
emh203 0:3d9c67d97d6f 392 *pState++ = Yn1;
emh203 0:3d9c67d97d6f 393 *pState++ = Yn2;
emh203 0:3d9c67d97d6f 394
emh203 0:3d9c67d97d6f 395 } while(--stage);
emh203 0:3d9c67d97d6f 396
emh203 0:3d9c67d97d6f 397 #endif /* #ifndef ARM_MATH_CM0_FAMILY_FAMILY */
emh203 0:3d9c67d97d6f 398 }
emh203 0:3d9c67d97d6f 399
emh203 0:3d9c67d97d6f 400
emh203 0:3d9c67d97d6f 401
emh203 0:3d9c67d97d6f 402
emh203 0:3d9c67d97d6f 403 /**
emh203 0:3d9c67d97d6f 404 * @} end of BiquadCascadeDF1 group
emh203 0:3d9c67d97d6f 405 */