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_q15.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_q15.c
emh203 0:3d9c67d97d6f 9 *
emh203 0:3d9c67d97d6f 10 * Description: Processing function for the
emh203 0:3d9c67d97d6f 11 * Q15 Biquad cascade DirectFormI(DF1) 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 Q15 Biquad cascade filter.
emh203 0:3d9c67d97d6f 55 * @param[in] *S points to an instance of the Q15 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 location where the output result is written.
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 *
emh203 0:3d9c67d97d6f 62 * <b>Scaling and Overflow Behavior:</b>
emh203 0:3d9c67d97d6f 63 * \par
emh203 0:3d9c67d97d6f 64 * The function is implemented using a 64-bit internal accumulator.
emh203 0:3d9c67d97d6f 65 * Both coefficients and state variables are represented in 1.15 format and multiplications yield a 2.30 result.
emh203 0:3d9c67d97d6f 66 * The 2.30 intermediate results are accumulated in a 64-bit accumulator in 34.30 format.
emh203 0:3d9c67d97d6f 67 * There is no risk of internal overflow with this approach and the full precision of intermediate multiplications is preserved.
emh203 0:3d9c67d97d6f 68 * The accumulator is then shifted by <code>postShift</code> bits to truncate the result to 1.15 format by discarding the low 16 bits.
emh203 0:3d9c67d97d6f 69 * Finally, the result is saturated to 1.15 format.
emh203 0:3d9c67d97d6f 70 *
emh203 0:3d9c67d97d6f 71 * \par
emh203 0:3d9c67d97d6f 72 * Refer to the function <code>arm_biquad_cascade_df1_fast_q15()</code> for a faster but less precise implementation of this filter for Cortex-M3 and Cortex-M4.
emh203 0:3d9c67d97d6f 73 */
emh203 0:3d9c67d97d6f 74
emh203 0:3d9c67d97d6f 75 void arm_biquad_cascade_df1_q15(
emh203 0:3d9c67d97d6f 76 const arm_biquad_casd_df1_inst_q15 * S,
emh203 0:3d9c67d97d6f 77 q15_t * pSrc,
emh203 0:3d9c67d97d6f 78 q15_t * pDst,
emh203 0:3d9c67d97d6f 79 uint32_t blockSize)
emh203 0:3d9c67d97d6f 80 {
emh203 0:3d9c67d97d6f 81
emh203 0:3d9c67d97d6f 82
emh203 0:3d9c67d97d6f 83 #ifndef ARM_MATH_CM0_FAMILY
emh203 0:3d9c67d97d6f 84
emh203 0:3d9c67d97d6f 85 /* Run the below code for Cortex-M4 and Cortex-M3 */
emh203 0:3d9c67d97d6f 86
emh203 0:3d9c67d97d6f 87 q15_t *pIn = pSrc; /* Source pointer */
emh203 0:3d9c67d97d6f 88 q15_t *pOut = pDst; /* Destination pointer */
emh203 0:3d9c67d97d6f 89 q31_t in; /* Temporary variable to hold input value */
emh203 0:3d9c67d97d6f 90 q31_t out; /* Temporary variable to hold output value */
emh203 0:3d9c67d97d6f 91 q31_t b0; /* Temporary variable to hold bo value */
emh203 0:3d9c67d97d6f 92 q31_t b1, a1; /* Filter coefficients */
emh203 0:3d9c67d97d6f 93 q31_t state_in, state_out; /* Filter state variables */
emh203 0:3d9c67d97d6f 94 q31_t acc_l, acc_h;
emh203 0:3d9c67d97d6f 95 q63_t acc; /* Accumulator */
emh203 0:3d9c67d97d6f 96 int32_t lShift = (15 - (int32_t) S->postShift); /* Post shift */
emh203 0:3d9c67d97d6f 97 q15_t *pState = S->pState; /* State pointer */
emh203 0:3d9c67d97d6f 98 q15_t *pCoeffs = S->pCoeffs; /* Coefficient pointer */
emh203 0:3d9c67d97d6f 99 uint32_t sample, stage = (uint32_t) S->numStages; /* Stage loop counter */
emh203 0:3d9c67d97d6f 100 int32_t uShift = (32 - lShift);
emh203 0:3d9c67d97d6f 101
emh203 0:3d9c67d97d6f 102 do
emh203 0:3d9c67d97d6f 103 {
emh203 0:3d9c67d97d6f 104 /* Read the b0 and 0 coefficients using SIMD */
emh203 0:3d9c67d97d6f 105 b0 = *__SIMD32(pCoeffs)++;
emh203 0:3d9c67d97d6f 106
emh203 0:3d9c67d97d6f 107 /* Read the b1 and b2 coefficients using SIMD */
emh203 0:3d9c67d97d6f 108 b1 = *__SIMD32(pCoeffs)++;
emh203 0:3d9c67d97d6f 109
emh203 0:3d9c67d97d6f 110 /* Read the a1 and a2 coefficients using SIMD */
emh203 0:3d9c67d97d6f 111 a1 = *__SIMD32(pCoeffs)++;
emh203 0:3d9c67d97d6f 112
emh203 0:3d9c67d97d6f 113 /* Read the input state values from the state buffer: x[n-1], x[n-2] */
emh203 0:3d9c67d97d6f 114 state_in = *__SIMD32(pState)++;
emh203 0:3d9c67d97d6f 115
emh203 0:3d9c67d97d6f 116 /* Read the output state values from the state buffer: y[n-1], y[n-2] */
emh203 0:3d9c67d97d6f 117 state_out = *__SIMD32(pState)--;
emh203 0:3d9c67d97d6f 118
emh203 0:3d9c67d97d6f 119 /* Apply loop unrolling and compute 2 output values simultaneously. */
emh203 0:3d9c67d97d6f 120 /* The variable acc hold output values that are being computed:
emh203 0:3d9c67d97d6f 121 *
emh203 0:3d9c67d97d6f 122 * acc = b0 * x[n] + b1 * x[n-1] + b2 * x[n-2] + a1 * y[n-1] + a2 * y[n-2]
emh203 0:3d9c67d97d6f 123 * acc = b0 * x[n] + b1 * x[n-1] + b2 * x[n-2] + a1 * y[n-1] + a2 * y[n-2]
emh203 0:3d9c67d97d6f 124 */
emh203 0:3d9c67d97d6f 125 sample = blockSize >> 1u;
emh203 0:3d9c67d97d6f 126
emh203 0:3d9c67d97d6f 127 /* First part of the processing with loop unrolling. Compute 2 outputs at a time.
emh203 0:3d9c67d97d6f 128 ** a second loop below computes the remaining 1 sample. */
emh203 0:3d9c67d97d6f 129 while(sample > 0u)
emh203 0:3d9c67d97d6f 130 {
emh203 0:3d9c67d97d6f 131
emh203 0:3d9c67d97d6f 132 /* Read the input */
emh203 0:3d9c67d97d6f 133 in = *__SIMD32(pIn)++;
emh203 0:3d9c67d97d6f 134
emh203 0:3d9c67d97d6f 135 /* out = b0 * x[n] + 0 * 0 */
emh203 0:3d9c67d97d6f 136 out = __SMUAD(b0, in);
emh203 0:3d9c67d97d6f 137
emh203 0:3d9c67d97d6f 138 /* acc += b1 * x[n-1] + b2 * x[n-2] + out */
emh203 0:3d9c67d97d6f 139 acc = __SMLALD(b1, state_in, out);
emh203 0:3d9c67d97d6f 140 /* acc += a1 * y[n-1] + a2 * y[n-2] */
emh203 0:3d9c67d97d6f 141 acc = __SMLALD(a1, state_out, acc);
emh203 0:3d9c67d97d6f 142
emh203 0:3d9c67d97d6f 143 /* The result is converted from 3.29 to 1.31 if postShift = 1, and then saturation is applied */
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 out = (uint32_t) acc_l >> lShift | acc_h << uShift;
emh203 0:3d9c67d97d6f 152
emh203 0:3d9c67d97d6f 153 out = __SSAT(out, 16);
emh203 0:3d9c67d97d6f 154
emh203 0:3d9c67d97d6f 155 /* Every time after the output is computed state should be updated. */
emh203 0:3d9c67d97d6f 156 /* The states should be updated as: */
emh203 0:3d9c67d97d6f 157 /* Xn2 = Xn1 */
emh203 0:3d9c67d97d6f 158 /* Xn1 = Xn */
emh203 0:3d9c67d97d6f 159 /* Yn2 = Yn1 */
emh203 0:3d9c67d97d6f 160 /* Yn1 = acc */
emh203 0:3d9c67d97d6f 161 /* x[n-N], x[n-N-1] are packed together to make state_in of type q31 */
emh203 0:3d9c67d97d6f 162 /* y[n-N], y[n-N-1] are packed together to make state_out of type q31 */
emh203 0:3d9c67d97d6f 163
emh203 0:3d9c67d97d6f 164 #ifndef ARM_MATH_BIG_ENDIAN
emh203 0:3d9c67d97d6f 165
emh203 0:3d9c67d97d6f 166 state_in = __PKHBT(in, state_in, 16);
emh203 0:3d9c67d97d6f 167 state_out = __PKHBT(out, state_out, 16);
emh203 0:3d9c67d97d6f 168
emh203 0:3d9c67d97d6f 169 #else
emh203 0:3d9c67d97d6f 170
emh203 0:3d9c67d97d6f 171 state_in = __PKHBT(state_in >> 16, (in >> 16), 16);
emh203 0:3d9c67d97d6f 172 state_out = __PKHBT(state_out >> 16, (out), 16);
emh203 0:3d9c67d97d6f 173
emh203 0:3d9c67d97d6f 174 #endif /* #ifndef ARM_MATH_BIG_ENDIAN */
emh203 0:3d9c67d97d6f 175
emh203 0:3d9c67d97d6f 176 /* out = b0 * x[n] + 0 * 0 */
emh203 0:3d9c67d97d6f 177 out = __SMUADX(b0, in);
emh203 0:3d9c67d97d6f 178 /* acc += b1 * x[n-1] + b2 * x[n-2] + out */
emh203 0:3d9c67d97d6f 179 acc = __SMLALD(b1, state_in, out);
emh203 0:3d9c67d97d6f 180 /* acc += a1 * y[n-1] + a2 * y[n-2] */
emh203 0:3d9c67d97d6f 181 acc = __SMLALD(a1, state_out, acc);
emh203 0:3d9c67d97d6f 182
emh203 0:3d9c67d97d6f 183 /* The result is converted from 3.29 to 1.31 if postShift = 1, and then saturation is applied */
emh203 0:3d9c67d97d6f 184 /* Calc lower part of acc */
emh203 0:3d9c67d97d6f 185 acc_l = acc & 0xffffffff;
emh203 0:3d9c67d97d6f 186
emh203 0:3d9c67d97d6f 187 /* Calc upper part of acc */
emh203 0:3d9c67d97d6f 188 acc_h = (acc >> 32) & 0xffffffff;
emh203 0:3d9c67d97d6f 189
emh203 0:3d9c67d97d6f 190 /* Apply shift for lower part of acc and upper part of acc */
emh203 0:3d9c67d97d6f 191 out = (uint32_t) acc_l >> lShift | acc_h << uShift;
emh203 0:3d9c67d97d6f 192
emh203 0:3d9c67d97d6f 193 out = __SSAT(out, 16);
emh203 0:3d9c67d97d6f 194
emh203 0:3d9c67d97d6f 195 /* Store the output in the destination buffer. */
emh203 0:3d9c67d97d6f 196
emh203 0:3d9c67d97d6f 197 #ifndef ARM_MATH_BIG_ENDIAN
emh203 0:3d9c67d97d6f 198
emh203 0:3d9c67d97d6f 199 *__SIMD32(pOut)++ = __PKHBT(state_out, out, 16);
emh203 0:3d9c67d97d6f 200
emh203 0:3d9c67d97d6f 201 #else
emh203 0:3d9c67d97d6f 202
emh203 0:3d9c67d97d6f 203 *__SIMD32(pOut)++ = __PKHBT(out, state_out >> 16, 16);
emh203 0:3d9c67d97d6f 204
emh203 0:3d9c67d97d6f 205 #endif /* #ifndef ARM_MATH_BIG_ENDIAN */
emh203 0:3d9c67d97d6f 206
emh203 0:3d9c67d97d6f 207 /* Every time after the output is computed state should be updated. */
emh203 0:3d9c67d97d6f 208 /* The states should be updated as: */
emh203 0:3d9c67d97d6f 209 /* Xn2 = Xn1 */
emh203 0:3d9c67d97d6f 210 /* Xn1 = Xn */
emh203 0:3d9c67d97d6f 211 /* Yn2 = Yn1 */
emh203 0:3d9c67d97d6f 212 /* Yn1 = acc */
emh203 0:3d9c67d97d6f 213 /* x[n-N], x[n-N-1] are packed together to make state_in of type q31 */
emh203 0:3d9c67d97d6f 214 /* y[n-N], y[n-N-1] are packed together to make state_out of type q31 */
emh203 0:3d9c67d97d6f 215 #ifndef ARM_MATH_BIG_ENDIAN
emh203 0:3d9c67d97d6f 216
emh203 0:3d9c67d97d6f 217 state_in = __PKHBT(in >> 16, state_in, 16);
emh203 0:3d9c67d97d6f 218 state_out = __PKHBT(out, state_out, 16);
emh203 0:3d9c67d97d6f 219
emh203 0:3d9c67d97d6f 220 #else
emh203 0:3d9c67d97d6f 221
emh203 0:3d9c67d97d6f 222 state_in = __PKHBT(state_in >> 16, in, 16);
emh203 0:3d9c67d97d6f 223 state_out = __PKHBT(state_out >> 16, out, 16);
emh203 0:3d9c67d97d6f 224
emh203 0:3d9c67d97d6f 225 #endif /* #ifndef ARM_MATH_BIG_ENDIAN */
emh203 0:3d9c67d97d6f 226
emh203 0:3d9c67d97d6f 227
emh203 0:3d9c67d97d6f 228 /* Decrement the loop counter */
emh203 0:3d9c67d97d6f 229 sample--;
emh203 0:3d9c67d97d6f 230
emh203 0:3d9c67d97d6f 231 }
emh203 0:3d9c67d97d6f 232
emh203 0:3d9c67d97d6f 233 /* If the blockSize is not a multiple of 2, compute any remaining output samples here.
emh203 0:3d9c67d97d6f 234 ** No loop unrolling is used. */
emh203 0:3d9c67d97d6f 235
emh203 0:3d9c67d97d6f 236 if((blockSize & 0x1u) != 0u)
emh203 0:3d9c67d97d6f 237 {
emh203 0:3d9c67d97d6f 238 /* Read the input */
emh203 0:3d9c67d97d6f 239 in = *pIn++;
emh203 0:3d9c67d97d6f 240
emh203 0:3d9c67d97d6f 241 /* out = b0 * x[n] + 0 * 0 */
emh203 0:3d9c67d97d6f 242
emh203 0:3d9c67d97d6f 243 #ifndef ARM_MATH_BIG_ENDIAN
emh203 0:3d9c67d97d6f 244
emh203 0:3d9c67d97d6f 245 out = __SMUAD(b0, in);
emh203 0:3d9c67d97d6f 246
emh203 0:3d9c67d97d6f 247 #else
emh203 0:3d9c67d97d6f 248
emh203 0:3d9c67d97d6f 249 out = __SMUADX(b0, in);
emh203 0:3d9c67d97d6f 250
emh203 0:3d9c67d97d6f 251 #endif /* #ifndef ARM_MATH_BIG_ENDIAN */
emh203 0:3d9c67d97d6f 252
emh203 0:3d9c67d97d6f 253 /* acc = b1 * x[n-1] + b2 * x[n-2] + out */
emh203 0:3d9c67d97d6f 254 acc = __SMLALD(b1, state_in, out);
emh203 0:3d9c67d97d6f 255 /* acc += a1 * y[n-1] + a2 * y[n-2] */
emh203 0:3d9c67d97d6f 256 acc = __SMLALD(a1, state_out, acc);
emh203 0:3d9c67d97d6f 257
emh203 0:3d9c67d97d6f 258 /* The result is converted from 3.29 to 1.31 if postShift = 1, and then saturation is applied */
emh203 0:3d9c67d97d6f 259 /* Calc lower part of acc */
emh203 0:3d9c67d97d6f 260 acc_l = acc & 0xffffffff;
emh203 0:3d9c67d97d6f 261
emh203 0:3d9c67d97d6f 262 /* Calc upper part of acc */
emh203 0:3d9c67d97d6f 263 acc_h = (acc >> 32) & 0xffffffff;
emh203 0:3d9c67d97d6f 264
emh203 0:3d9c67d97d6f 265 /* Apply shift for lower part of acc and upper part of acc */
emh203 0:3d9c67d97d6f 266 out = (uint32_t) acc_l >> lShift | acc_h << uShift;
emh203 0:3d9c67d97d6f 267
emh203 0:3d9c67d97d6f 268 out = __SSAT(out, 16);
emh203 0:3d9c67d97d6f 269
emh203 0:3d9c67d97d6f 270 /* Store the output in the destination buffer. */
emh203 0:3d9c67d97d6f 271 *pOut++ = (q15_t) out;
emh203 0:3d9c67d97d6f 272
emh203 0:3d9c67d97d6f 273 /* Every time after the output is computed state should be updated. */
emh203 0:3d9c67d97d6f 274 /* The states should be updated as: */
emh203 0:3d9c67d97d6f 275 /* Xn2 = Xn1 */
emh203 0:3d9c67d97d6f 276 /* Xn1 = Xn */
emh203 0:3d9c67d97d6f 277 /* Yn2 = Yn1 */
emh203 0:3d9c67d97d6f 278 /* Yn1 = acc */
emh203 0:3d9c67d97d6f 279 /* x[n-N], x[n-N-1] are packed together to make state_in of type q31 */
emh203 0:3d9c67d97d6f 280 /* y[n-N], y[n-N-1] are packed together to make state_out of type q31 */
emh203 0:3d9c67d97d6f 281
emh203 0:3d9c67d97d6f 282 #ifndef ARM_MATH_BIG_ENDIAN
emh203 0:3d9c67d97d6f 283
emh203 0:3d9c67d97d6f 284 state_in = __PKHBT(in, state_in, 16);
emh203 0:3d9c67d97d6f 285 state_out = __PKHBT(out, state_out, 16);
emh203 0:3d9c67d97d6f 286
emh203 0:3d9c67d97d6f 287 #else
emh203 0:3d9c67d97d6f 288
emh203 0:3d9c67d97d6f 289 state_in = __PKHBT(state_in >> 16, in, 16);
emh203 0:3d9c67d97d6f 290 state_out = __PKHBT(state_out >> 16, out, 16);
emh203 0:3d9c67d97d6f 291
emh203 0:3d9c67d97d6f 292 #endif /* #ifndef ARM_MATH_BIG_ENDIAN */
emh203 0:3d9c67d97d6f 293
emh203 0:3d9c67d97d6f 294 }
emh203 0:3d9c67d97d6f 295
emh203 0:3d9c67d97d6f 296 /* The first stage goes from the input wire to the output wire. */
emh203 0:3d9c67d97d6f 297 /* Subsequent numStages occur in-place in the output wire */
emh203 0:3d9c67d97d6f 298 pIn = pDst;
emh203 0:3d9c67d97d6f 299
emh203 0:3d9c67d97d6f 300 /* Reset the output pointer */
emh203 0:3d9c67d97d6f 301 pOut = pDst;
emh203 0:3d9c67d97d6f 302
emh203 0:3d9c67d97d6f 303 /* Store the updated state variables back into the state array */
emh203 0:3d9c67d97d6f 304 *__SIMD32(pState)++ = state_in;
emh203 0:3d9c67d97d6f 305 *__SIMD32(pState)++ = state_out;
emh203 0:3d9c67d97d6f 306
emh203 0:3d9c67d97d6f 307
emh203 0:3d9c67d97d6f 308 /* Decrement the loop counter */
emh203 0:3d9c67d97d6f 309 stage--;
emh203 0:3d9c67d97d6f 310
emh203 0:3d9c67d97d6f 311 } while(stage > 0u);
emh203 0:3d9c67d97d6f 312
emh203 0:3d9c67d97d6f 313 #else
emh203 0:3d9c67d97d6f 314
emh203 0:3d9c67d97d6f 315 /* Run the below code for Cortex-M0 */
emh203 0:3d9c67d97d6f 316
emh203 0:3d9c67d97d6f 317 q15_t *pIn = pSrc; /* Source pointer */
emh203 0:3d9c67d97d6f 318 q15_t *pOut = pDst; /* Destination pointer */
emh203 0:3d9c67d97d6f 319 q15_t b0, b1, b2, a1, a2; /* Filter coefficients */
emh203 0:3d9c67d97d6f 320 q15_t Xn1, Xn2, Yn1, Yn2; /* Filter state variables */
emh203 0:3d9c67d97d6f 321 q15_t Xn; /* temporary input */
emh203 0:3d9c67d97d6f 322 q63_t acc; /* Accumulator */
emh203 0:3d9c67d97d6f 323 int32_t shift = (15 - (int32_t) S->postShift); /* Post shift */
emh203 0:3d9c67d97d6f 324 q15_t *pState = S->pState; /* State pointer */
emh203 0:3d9c67d97d6f 325 q15_t *pCoeffs = S->pCoeffs; /* Coefficient pointer */
emh203 0:3d9c67d97d6f 326 uint32_t sample, stage = (uint32_t) S->numStages; /* Stage loop counter */
emh203 0:3d9c67d97d6f 327
emh203 0:3d9c67d97d6f 328 do
emh203 0:3d9c67d97d6f 329 {
emh203 0:3d9c67d97d6f 330 /* Reading the coefficients */
emh203 0:3d9c67d97d6f 331 b0 = *pCoeffs++;
emh203 0:3d9c67d97d6f 332 pCoeffs++; // skip the 0 coefficient
emh203 0:3d9c67d97d6f 333 b1 = *pCoeffs++;
emh203 0:3d9c67d97d6f 334 b2 = *pCoeffs++;
emh203 0:3d9c67d97d6f 335 a1 = *pCoeffs++;
emh203 0:3d9c67d97d6f 336 a2 = *pCoeffs++;
emh203 0:3d9c67d97d6f 337
emh203 0:3d9c67d97d6f 338 /* Reading the state values */
emh203 0:3d9c67d97d6f 339 Xn1 = pState[0];
emh203 0:3d9c67d97d6f 340 Xn2 = pState[1];
emh203 0:3d9c67d97d6f 341 Yn1 = pState[2];
emh203 0:3d9c67d97d6f 342 Yn2 = pState[3];
emh203 0:3d9c67d97d6f 343
emh203 0:3d9c67d97d6f 344 /* The variables acc holds the output value that is computed:
emh203 0:3d9c67d97d6f 345 * acc = b0 * x[n] + b1 * x[n-1] + b2 * x[n-2] + a1 * y[n-1] + a2 * y[n-2]
emh203 0:3d9c67d97d6f 346 */
emh203 0:3d9c67d97d6f 347
emh203 0:3d9c67d97d6f 348 sample = blockSize;
emh203 0:3d9c67d97d6f 349
emh203 0:3d9c67d97d6f 350 while(sample > 0u)
emh203 0:3d9c67d97d6f 351 {
emh203 0:3d9c67d97d6f 352 /* Read the input */
emh203 0:3d9c67d97d6f 353 Xn = *pIn++;
emh203 0:3d9c67d97d6f 354
emh203 0:3d9c67d97d6f 355 /* acc = b0 * x[n] + b1 * x[n-1] + b2 * x[n-2] + a1 * y[n-1] + a2 * y[n-2] */
emh203 0:3d9c67d97d6f 356 /* acc = b0 * x[n] */
emh203 0:3d9c67d97d6f 357 acc = (q31_t) b0 *Xn;
emh203 0:3d9c67d97d6f 358
emh203 0:3d9c67d97d6f 359 /* acc += b1 * x[n-1] */
emh203 0:3d9c67d97d6f 360 acc += (q31_t) b1 *Xn1;
emh203 0:3d9c67d97d6f 361 /* acc += b[2] * x[n-2] */
emh203 0:3d9c67d97d6f 362 acc += (q31_t) b2 *Xn2;
emh203 0:3d9c67d97d6f 363 /* acc += a1 * y[n-1] */
emh203 0:3d9c67d97d6f 364 acc += (q31_t) a1 *Yn1;
emh203 0:3d9c67d97d6f 365 /* acc += a2 * y[n-2] */
emh203 0:3d9c67d97d6f 366 acc += (q31_t) a2 *Yn2;
emh203 0:3d9c67d97d6f 367
emh203 0:3d9c67d97d6f 368 /* The result is converted to 1.31 */
emh203 0:3d9c67d97d6f 369 acc = __SSAT((acc >> shift), 16);
emh203 0:3d9c67d97d6f 370
emh203 0:3d9c67d97d6f 371 /* Every time after the output is computed state should be updated. */
emh203 0:3d9c67d97d6f 372 /* The states should be updated as: */
emh203 0:3d9c67d97d6f 373 /* Xn2 = Xn1 */
emh203 0:3d9c67d97d6f 374 /* Xn1 = Xn */
emh203 0:3d9c67d97d6f 375 /* Yn2 = Yn1 */
emh203 0:3d9c67d97d6f 376 /* Yn1 = acc */
emh203 0:3d9c67d97d6f 377 Xn2 = Xn1;
emh203 0:3d9c67d97d6f 378 Xn1 = Xn;
emh203 0:3d9c67d97d6f 379 Yn2 = Yn1;
emh203 0:3d9c67d97d6f 380 Yn1 = (q15_t) acc;
emh203 0:3d9c67d97d6f 381
emh203 0:3d9c67d97d6f 382 /* Store the output in the destination buffer. */
emh203 0:3d9c67d97d6f 383 *pOut++ = (q15_t) acc;
emh203 0:3d9c67d97d6f 384
emh203 0:3d9c67d97d6f 385 /* decrement the loop counter */
emh203 0:3d9c67d97d6f 386 sample--;
emh203 0:3d9c67d97d6f 387 }
emh203 0:3d9c67d97d6f 388
emh203 0:3d9c67d97d6f 389 /* The first stage goes from the input buffer to the output buffer. */
emh203 0:3d9c67d97d6f 390 /* Subsequent stages occur in-place in the output buffer */
emh203 0:3d9c67d97d6f 391 pIn = pDst;
emh203 0:3d9c67d97d6f 392
emh203 0:3d9c67d97d6f 393 /* Reset to destination pointer */
emh203 0:3d9c67d97d6f 394 pOut = pDst;
emh203 0:3d9c67d97d6f 395
emh203 0:3d9c67d97d6f 396 /* Store the updated state variables back into the pState array */
emh203 0:3d9c67d97d6f 397 *pState++ = Xn1;
emh203 0:3d9c67d97d6f 398 *pState++ = Xn2;
emh203 0:3d9c67d97d6f 399 *pState++ = Yn1;
emh203 0:3d9c67d97d6f 400 *pState++ = Yn2;
emh203 0:3d9c67d97d6f 401
emh203 0:3d9c67d97d6f 402 } while(--stage);
emh203 0:3d9c67d97d6f 403
emh203 0:3d9c67d97d6f 404 #endif /* #ifndef ARM_MATH_CM0_FAMILY */
emh203 0:3d9c67d97d6f 405
emh203 0:3d9c67d97d6f 406 }
emh203 0:3d9c67d97d6f 407
emh203 0:3d9c67d97d6f 408
emh203 0:3d9c67d97d6f 409 /**
emh203 0:3d9c67d97d6f 410 * @} end of BiquadCascadeDF1 group
emh203 0:3d9c67d97d6f 411 */