CMSIS DSP library
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cmsis_dsp/FilteringFunctions/arm_iir_lattice_q31.c@1:fdd22bb7aa52, 2012-11-28 (annotated)
- Committer:
- emilmont
- Date:
- Wed Nov 28 12:30:09 2012 +0000
- Revision:
- 1:fdd22bb7aa52
- Child:
- 2:da51fb522205
DSP library code
Who changed what in which revision?
User | Revision | Line number | New contents of line |
---|---|---|---|
emilmont | 1:fdd22bb7aa52 | 1 | /* ---------------------------------------------------------------------- |
emilmont | 1:fdd22bb7aa52 | 2 | * Copyright (C) 2010 ARM Limited. All rights reserved. |
emilmont | 1:fdd22bb7aa52 | 3 | * |
emilmont | 1:fdd22bb7aa52 | 4 | * $Date: 15. February 2012 |
emilmont | 1:fdd22bb7aa52 | 5 | * $Revision: V1.1.0 |
emilmont | 1:fdd22bb7aa52 | 6 | * |
emilmont | 1:fdd22bb7aa52 | 7 | * Project: CMSIS DSP Library |
emilmont | 1:fdd22bb7aa52 | 8 | * Title: arm_iir_lattice_q31.c |
emilmont | 1:fdd22bb7aa52 | 9 | * |
emilmont | 1:fdd22bb7aa52 | 10 | * Description: Q31 IIR lattice filter processing function. |
emilmont | 1:fdd22bb7aa52 | 11 | * |
emilmont | 1:fdd22bb7aa52 | 12 | * Target Processor: Cortex-M4/Cortex-M3/Cortex-M0 |
emilmont | 1:fdd22bb7aa52 | 13 | * |
emilmont | 1:fdd22bb7aa52 | 14 | * Version 1.1.0 2012/02/15 |
emilmont | 1:fdd22bb7aa52 | 15 | * Updated with more optimizations, bug fixes and minor API changes. |
emilmont | 1:fdd22bb7aa52 | 16 | * |
emilmont | 1:fdd22bb7aa52 | 17 | * Version 1.0.10 2011/7/15 |
emilmont | 1:fdd22bb7aa52 | 18 | * Big Endian support added and Merged M0 and M3/M4 Source code. |
emilmont | 1:fdd22bb7aa52 | 19 | * |
emilmont | 1:fdd22bb7aa52 | 20 | * Version 1.0.3 2010/11/29 |
emilmont | 1:fdd22bb7aa52 | 21 | * Re-organized the CMSIS folders and updated documentation. |
emilmont | 1:fdd22bb7aa52 | 22 | * |
emilmont | 1:fdd22bb7aa52 | 23 | * Version 1.0.2 2010/11/11 |
emilmont | 1:fdd22bb7aa52 | 24 | * Documentation updated. |
emilmont | 1:fdd22bb7aa52 | 25 | * |
emilmont | 1:fdd22bb7aa52 | 26 | * Version 1.0.1 2010/10/05 |
emilmont | 1:fdd22bb7aa52 | 27 | * Production release and review comments incorporated. |
emilmont | 1:fdd22bb7aa52 | 28 | * |
emilmont | 1:fdd22bb7aa52 | 29 | * Version 1.0.0 2010/09/20 |
emilmont | 1:fdd22bb7aa52 | 30 | * Production release and review comments incorporated |
emilmont | 1:fdd22bb7aa52 | 31 | * |
emilmont | 1:fdd22bb7aa52 | 32 | * Version 0.0.7 2010/06/10 |
emilmont | 1:fdd22bb7aa52 | 33 | * Misra-C changes done |
emilmont | 1:fdd22bb7aa52 | 34 | * -------------------------------------------------------------------- */ |
emilmont | 1:fdd22bb7aa52 | 35 | |
emilmont | 1:fdd22bb7aa52 | 36 | #include "arm_math.h" |
emilmont | 1:fdd22bb7aa52 | 37 | |
emilmont | 1:fdd22bb7aa52 | 38 | /** |
emilmont | 1:fdd22bb7aa52 | 39 | * @ingroup groupFilters |
emilmont | 1:fdd22bb7aa52 | 40 | */ |
emilmont | 1:fdd22bb7aa52 | 41 | |
emilmont | 1:fdd22bb7aa52 | 42 | /** |
emilmont | 1:fdd22bb7aa52 | 43 | * @addtogroup IIR_Lattice |
emilmont | 1:fdd22bb7aa52 | 44 | * @{ |
emilmont | 1:fdd22bb7aa52 | 45 | */ |
emilmont | 1:fdd22bb7aa52 | 46 | |
emilmont | 1:fdd22bb7aa52 | 47 | /** |
emilmont | 1:fdd22bb7aa52 | 48 | * @brief Processing function for the Q31 IIR lattice filter. |
emilmont | 1:fdd22bb7aa52 | 49 | * @param[in] *S points to an instance of the Q31 IIR lattice structure. |
emilmont | 1:fdd22bb7aa52 | 50 | * @param[in] *pSrc points to the block of input data. |
emilmont | 1:fdd22bb7aa52 | 51 | * @param[out] *pDst points to the block of output data. |
emilmont | 1:fdd22bb7aa52 | 52 | * @param[in] blockSize number of samples to process. |
emilmont | 1:fdd22bb7aa52 | 53 | * @return none. |
emilmont | 1:fdd22bb7aa52 | 54 | * |
emilmont | 1:fdd22bb7aa52 | 55 | * @details |
emilmont | 1:fdd22bb7aa52 | 56 | * <b>Scaling and Overflow Behavior:</b> |
emilmont | 1:fdd22bb7aa52 | 57 | * \par |
emilmont | 1:fdd22bb7aa52 | 58 | * The function is implemented using an internal 64-bit accumulator. |
emilmont | 1:fdd22bb7aa52 | 59 | * The accumulator has a 2.62 format and maintains full precision of the intermediate multiplication results but provides only a single guard bit. |
emilmont | 1:fdd22bb7aa52 | 60 | * Thus, if the accumulator result overflows it wraps around rather than clip. |
emilmont | 1:fdd22bb7aa52 | 61 | * In order to avoid overflows completely the input signal must be scaled down by 2*log2(numStages) bits. |
emilmont | 1:fdd22bb7aa52 | 62 | * After all multiply-accumulates are performed, the 2.62 accumulator is saturated to 1.32 format and then truncated to 1.31 format. |
emilmont | 1:fdd22bb7aa52 | 63 | */ |
emilmont | 1:fdd22bb7aa52 | 64 | |
emilmont | 1:fdd22bb7aa52 | 65 | void arm_iir_lattice_q31( |
emilmont | 1:fdd22bb7aa52 | 66 | const arm_iir_lattice_instance_q31 * S, |
emilmont | 1:fdd22bb7aa52 | 67 | q31_t * pSrc, |
emilmont | 1:fdd22bb7aa52 | 68 | q31_t * pDst, |
emilmont | 1:fdd22bb7aa52 | 69 | uint32_t blockSize) |
emilmont | 1:fdd22bb7aa52 | 70 | { |
emilmont | 1:fdd22bb7aa52 | 71 | q31_t fcurr, fnext = 0, gcurr = 0, gnext; /* Temporary variables for lattice stages */ |
emilmont | 1:fdd22bb7aa52 | 72 | q63_t acc; /* Accumlator */ |
emilmont | 1:fdd22bb7aa52 | 73 | uint32_t blkCnt, tapCnt; /* Temporary variables for counts */ |
emilmont | 1:fdd22bb7aa52 | 74 | q31_t *px1, *px2, *pk, *pv; /* Temporary pointers for state and coef */ |
emilmont | 1:fdd22bb7aa52 | 75 | uint32_t numStages = S->numStages; /* number of stages */ |
emilmont | 1:fdd22bb7aa52 | 76 | q31_t *pState; /* State pointer */ |
emilmont | 1:fdd22bb7aa52 | 77 | q31_t *pStateCurnt; /* State current pointer */ |
emilmont | 1:fdd22bb7aa52 | 78 | |
emilmont | 1:fdd22bb7aa52 | 79 | blkCnt = blockSize; |
emilmont | 1:fdd22bb7aa52 | 80 | |
emilmont | 1:fdd22bb7aa52 | 81 | pState = &S->pState[0]; |
emilmont | 1:fdd22bb7aa52 | 82 | |
emilmont | 1:fdd22bb7aa52 | 83 | |
emilmont | 1:fdd22bb7aa52 | 84 | #ifndef ARM_MATH_CM0 |
emilmont | 1:fdd22bb7aa52 | 85 | |
emilmont | 1:fdd22bb7aa52 | 86 | /* Run the below code for Cortex-M4 and Cortex-M3 */ |
emilmont | 1:fdd22bb7aa52 | 87 | |
emilmont | 1:fdd22bb7aa52 | 88 | /* Sample processing */ |
emilmont | 1:fdd22bb7aa52 | 89 | while(blkCnt > 0u) |
emilmont | 1:fdd22bb7aa52 | 90 | { |
emilmont | 1:fdd22bb7aa52 | 91 | /* Read Sample from input buffer */ |
emilmont | 1:fdd22bb7aa52 | 92 | /* fN(n) = x(n) */ |
emilmont | 1:fdd22bb7aa52 | 93 | fcurr = *pSrc++; |
emilmont | 1:fdd22bb7aa52 | 94 | |
emilmont | 1:fdd22bb7aa52 | 95 | /* Initialize state read pointer */ |
emilmont | 1:fdd22bb7aa52 | 96 | px1 = pState; |
emilmont | 1:fdd22bb7aa52 | 97 | /* Initialize state write pointer */ |
emilmont | 1:fdd22bb7aa52 | 98 | px2 = pState; |
emilmont | 1:fdd22bb7aa52 | 99 | /* Set accumulator to zero */ |
emilmont | 1:fdd22bb7aa52 | 100 | acc = 0; |
emilmont | 1:fdd22bb7aa52 | 101 | /* Initialize Ladder coeff pointer */ |
emilmont | 1:fdd22bb7aa52 | 102 | pv = &S->pvCoeffs[0]; |
emilmont | 1:fdd22bb7aa52 | 103 | /* Initialize Reflection coeff pointer */ |
emilmont | 1:fdd22bb7aa52 | 104 | pk = &S->pkCoeffs[0]; |
emilmont | 1:fdd22bb7aa52 | 105 | |
emilmont | 1:fdd22bb7aa52 | 106 | |
emilmont | 1:fdd22bb7aa52 | 107 | /* Process sample for first tap */ |
emilmont | 1:fdd22bb7aa52 | 108 | gcurr = *px1++; |
emilmont | 1:fdd22bb7aa52 | 109 | /* fN-1(n) = fN(n) - kN * gN-1(n-1) */ |
emilmont | 1:fdd22bb7aa52 | 110 | fnext = __QSUB(fcurr, (q31_t) (((q63_t) gcurr * (*pk)) >> 31)); |
emilmont | 1:fdd22bb7aa52 | 111 | /* gN(n) = kN * fN-1(n) + gN-1(n-1) */ |
emilmont | 1:fdd22bb7aa52 | 112 | gnext = __QADD(gcurr, (q31_t) (((q63_t) fnext * (*pk++)) >> 31)); |
emilmont | 1:fdd22bb7aa52 | 113 | /* write gN-1(n-1) into state for next sample processing */ |
emilmont | 1:fdd22bb7aa52 | 114 | *px2++ = gnext; |
emilmont | 1:fdd22bb7aa52 | 115 | /* y(n) += gN(n) * vN */ |
emilmont | 1:fdd22bb7aa52 | 116 | acc += ((q63_t) gnext * *pv++); |
emilmont | 1:fdd22bb7aa52 | 117 | |
emilmont | 1:fdd22bb7aa52 | 118 | /* Update f values for next coefficient processing */ |
emilmont | 1:fdd22bb7aa52 | 119 | fcurr = fnext; |
emilmont | 1:fdd22bb7aa52 | 120 | |
emilmont | 1:fdd22bb7aa52 | 121 | /* Loop unrolling. Process 4 taps at a time. */ |
emilmont | 1:fdd22bb7aa52 | 122 | tapCnt = (numStages - 1u) >> 2; |
emilmont | 1:fdd22bb7aa52 | 123 | |
emilmont | 1:fdd22bb7aa52 | 124 | while(tapCnt > 0u) |
emilmont | 1:fdd22bb7aa52 | 125 | { |
emilmont | 1:fdd22bb7aa52 | 126 | |
emilmont | 1:fdd22bb7aa52 | 127 | /* Process sample for 2nd, 6th .. taps */ |
emilmont | 1:fdd22bb7aa52 | 128 | /* Read gN-2(n-1) from state buffer */ |
emilmont | 1:fdd22bb7aa52 | 129 | gcurr = *px1++; |
emilmont | 1:fdd22bb7aa52 | 130 | /* fN-2(n) = fN-1(n) - kN-1 * gN-2(n-1) */ |
emilmont | 1:fdd22bb7aa52 | 131 | fnext = __QSUB(fcurr, (q31_t) (((q63_t) gcurr * (*pk)) >> 31)); |
emilmont | 1:fdd22bb7aa52 | 132 | /* gN-1(n) = kN-1 * fN-2(n) + gN-2(n-1) */ |
emilmont | 1:fdd22bb7aa52 | 133 | gnext = __QADD(gcurr, (q31_t) (((q63_t) fnext * (*pk++)) >> 31)); |
emilmont | 1:fdd22bb7aa52 | 134 | /* y(n) += gN-1(n) * vN-1 */ |
emilmont | 1:fdd22bb7aa52 | 135 | /* process for gN-5(n) * vN-5, gN-9(n) * vN-9 ... */ |
emilmont | 1:fdd22bb7aa52 | 136 | acc += ((q63_t) gnext * *pv++); |
emilmont | 1:fdd22bb7aa52 | 137 | /* write gN-1(n) into state for next sample processing */ |
emilmont | 1:fdd22bb7aa52 | 138 | *px2++ = gnext; |
emilmont | 1:fdd22bb7aa52 | 139 | |
emilmont | 1:fdd22bb7aa52 | 140 | /* Process sample for 3nd, 7th ...taps */ |
emilmont | 1:fdd22bb7aa52 | 141 | /* Read gN-3(n-1) from state buffer */ |
emilmont | 1:fdd22bb7aa52 | 142 | gcurr = *px1++; |
emilmont | 1:fdd22bb7aa52 | 143 | /* Process sample for 3rd, 7th .. taps */ |
emilmont | 1:fdd22bb7aa52 | 144 | /* fN-3(n) = fN-2(n) - kN-2 * gN-3(n-1) */ |
emilmont | 1:fdd22bb7aa52 | 145 | fcurr = __QSUB(fnext, (q31_t) (((q63_t) gcurr * (*pk)) >> 31)); |
emilmont | 1:fdd22bb7aa52 | 146 | /* gN-2(n) = kN-2 * fN-3(n) + gN-3(n-1) */ |
emilmont | 1:fdd22bb7aa52 | 147 | gnext = __QADD(gcurr, (q31_t) (((q63_t) fcurr * (*pk++)) >> 31)); |
emilmont | 1:fdd22bb7aa52 | 148 | /* y(n) += gN-2(n) * vN-2 */ |
emilmont | 1:fdd22bb7aa52 | 149 | /* process for gN-6(n) * vN-6, gN-10(n) * vN-10 ... */ |
emilmont | 1:fdd22bb7aa52 | 150 | acc += ((q63_t) gnext * *pv++); |
emilmont | 1:fdd22bb7aa52 | 151 | /* write gN-2(n) into state for next sample processing */ |
emilmont | 1:fdd22bb7aa52 | 152 | *px2++ = gnext; |
emilmont | 1:fdd22bb7aa52 | 153 | |
emilmont | 1:fdd22bb7aa52 | 154 | |
emilmont | 1:fdd22bb7aa52 | 155 | /* Process sample for 4th, 8th ...taps */ |
emilmont | 1:fdd22bb7aa52 | 156 | /* Read gN-4(n-1) from state buffer */ |
emilmont | 1:fdd22bb7aa52 | 157 | gcurr = *px1++; |
emilmont | 1:fdd22bb7aa52 | 158 | /* Process sample for 4th, 8th .. taps */ |
emilmont | 1:fdd22bb7aa52 | 159 | /* fN-4(n) = fN-3(n) - kN-3 * gN-4(n-1) */ |
emilmont | 1:fdd22bb7aa52 | 160 | fnext = __QSUB(fcurr, (q31_t) (((q63_t) gcurr * (*pk)) >> 31)); |
emilmont | 1:fdd22bb7aa52 | 161 | /* gN-3(n) = kN-3 * fN-4(n) + gN-4(n-1) */ |
emilmont | 1:fdd22bb7aa52 | 162 | gnext = __QADD(gcurr, (q31_t) (((q63_t) fnext * (*pk++)) >> 31)); |
emilmont | 1:fdd22bb7aa52 | 163 | /* y(n) += gN-3(n) * vN-3 */ |
emilmont | 1:fdd22bb7aa52 | 164 | /* process for gN-7(n) * vN-7, gN-11(n) * vN-11 ... */ |
emilmont | 1:fdd22bb7aa52 | 165 | acc += ((q63_t) gnext * *pv++); |
emilmont | 1:fdd22bb7aa52 | 166 | /* write gN-3(n) into state for next sample processing */ |
emilmont | 1:fdd22bb7aa52 | 167 | *px2++ = gnext; |
emilmont | 1:fdd22bb7aa52 | 168 | |
emilmont | 1:fdd22bb7aa52 | 169 | |
emilmont | 1:fdd22bb7aa52 | 170 | /* Process sample for 5th, 9th ...taps */ |
emilmont | 1:fdd22bb7aa52 | 171 | /* Read gN-5(n-1) from state buffer */ |
emilmont | 1:fdd22bb7aa52 | 172 | gcurr = *px1++; |
emilmont | 1:fdd22bb7aa52 | 173 | /* Process sample for 5th, 9th .. taps */ |
emilmont | 1:fdd22bb7aa52 | 174 | /* fN-5(n) = fN-4(n) - kN-4 * gN-1(n-1) */ |
emilmont | 1:fdd22bb7aa52 | 175 | fcurr = __QSUB(fnext, (q31_t) (((q63_t) gcurr * (*pk)) >> 31)); |
emilmont | 1:fdd22bb7aa52 | 176 | /* gN-4(n) = kN-4 * fN-5(n) + gN-5(n-1) */ |
emilmont | 1:fdd22bb7aa52 | 177 | gnext = __QADD(gcurr, (q31_t) (((q63_t) fcurr * (*pk++)) >> 31)); |
emilmont | 1:fdd22bb7aa52 | 178 | /* y(n) += gN-4(n) * vN-4 */ |
emilmont | 1:fdd22bb7aa52 | 179 | /* process for gN-8(n) * vN-8, gN-12(n) * vN-12 ... */ |
emilmont | 1:fdd22bb7aa52 | 180 | acc += ((q63_t) gnext * *pv++); |
emilmont | 1:fdd22bb7aa52 | 181 | /* write gN-4(n) into state for next sample processing */ |
emilmont | 1:fdd22bb7aa52 | 182 | *px2++ = gnext; |
emilmont | 1:fdd22bb7aa52 | 183 | |
emilmont | 1:fdd22bb7aa52 | 184 | tapCnt--; |
emilmont | 1:fdd22bb7aa52 | 185 | |
emilmont | 1:fdd22bb7aa52 | 186 | } |
emilmont | 1:fdd22bb7aa52 | 187 | |
emilmont | 1:fdd22bb7aa52 | 188 | fnext = fcurr; |
emilmont | 1:fdd22bb7aa52 | 189 | |
emilmont | 1:fdd22bb7aa52 | 190 | /* If the filter length is not a multiple of 4, compute the remaining filter taps */ |
emilmont | 1:fdd22bb7aa52 | 191 | tapCnt = (numStages - 1u) % 0x4u; |
emilmont | 1:fdd22bb7aa52 | 192 | |
emilmont | 1:fdd22bb7aa52 | 193 | while(tapCnt > 0u) |
emilmont | 1:fdd22bb7aa52 | 194 | { |
emilmont | 1:fdd22bb7aa52 | 195 | gcurr = *px1++; |
emilmont | 1:fdd22bb7aa52 | 196 | /* Process sample for last taps */ |
emilmont | 1:fdd22bb7aa52 | 197 | fnext = __QSUB(fcurr, (q31_t) (((q63_t) gcurr * (*pk)) >> 31)); |
emilmont | 1:fdd22bb7aa52 | 198 | gnext = __QADD(gcurr, (q31_t) (((q63_t) fnext * (*pk++)) >> 31)); |
emilmont | 1:fdd22bb7aa52 | 199 | /* Output samples for last taps */ |
emilmont | 1:fdd22bb7aa52 | 200 | acc += ((q63_t) gnext * *pv++); |
emilmont | 1:fdd22bb7aa52 | 201 | *px2++ = gnext; |
emilmont | 1:fdd22bb7aa52 | 202 | fcurr = fnext; |
emilmont | 1:fdd22bb7aa52 | 203 | |
emilmont | 1:fdd22bb7aa52 | 204 | tapCnt--; |
emilmont | 1:fdd22bb7aa52 | 205 | |
emilmont | 1:fdd22bb7aa52 | 206 | } |
emilmont | 1:fdd22bb7aa52 | 207 | |
emilmont | 1:fdd22bb7aa52 | 208 | /* y(n) += g0(n) * v0 */ |
emilmont | 1:fdd22bb7aa52 | 209 | acc += (q63_t) fnext *( |
emilmont | 1:fdd22bb7aa52 | 210 | *pv++); |
emilmont | 1:fdd22bb7aa52 | 211 | |
emilmont | 1:fdd22bb7aa52 | 212 | *px2++ = fnext; |
emilmont | 1:fdd22bb7aa52 | 213 | |
emilmont | 1:fdd22bb7aa52 | 214 | /* write out into pDst */ |
emilmont | 1:fdd22bb7aa52 | 215 | *pDst++ = (q31_t) (acc >> 31u); |
emilmont | 1:fdd22bb7aa52 | 216 | |
emilmont | 1:fdd22bb7aa52 | 217 | /* Advance the state pointer by 4 to process the next group of 4 samples */ |
emilmont | 1:fdd22bb7aa52 | 218 | pState = pState + 1u; |
emilmont | 1:fdd22bb7aa52 | 219 | blkCnt--; |
emilmont | 1:fdd22bb7aa52 | 220 | |
emilmont | 1:fdd22bb7aa52 | 221 | } |
emilmont | 1:fdd22bb7aa52 | 222 | |
emilmont | 1:fdd22bb7aa52 | 223 | /* Processing is complete. Now copy last S->numStages samples to start of the buffer |
emilmont | 1:fdd22bb7aa52 | 224 | for the preperation of next frame process */ |
emilmont | 1:fdd22bb7aa52 | 225 | |
emilmont | 1:fdd22bb7aa52 | 226 | /* Points to the start of the state buffer */ |
emilmont | 1:fdd22bb7aa52 | 227 | pStateCurnt = &S->pState[0]; |
emilmont | 1:fdd22bb7aa52 | 228 | pState = &S->pState[blockSize]; |
emilmont | 1:fdd22bb7aa52 | 229 | |
emilmont | 1:fdd22bb7aa52 | 230 | tapCnt = numStages >> 2u; |
emilmont | 1:fdd22bb7aa52 | 231 | |
emilmont | 1:fdd22bb7aa52 | 232 | /* copy data */ |
emilmont | 1:fdd22bb7aa52 | 233 | while(tapCnt > 0u) |
emilmont | 1:fdd22bb7aa52 | 234 | { |
emilmont | 1:fdd22bb7aa52 | 235 | *pStateCurnt++ = *pState++; |
emilmont | 1:fdd22bb7aa52 | 236 | *pStateCurnt++ = *pState++; |
emilmont | 1:fdd22bb7aa52 | 237 | *pStateCurnt++ = *pState++; |
emilmont | 1:fdd22bb7aa52 | 238 | *pStateCurnt++ = *pState++; |
emilmont | 1:fdd22bb7aa52 | 239 | |
emilmont | 1:fdd22bb7aa52 | 240 | /* Decrement the loop counter */ |
emilmont | 1:fdd22bb7aa52 | 241 | tapCnt--; |
emilmont | 1:fdd22bb7aa52 | 242 | |
emilmont | 1:fdd22bb7aa52 | 243 | } |
emilmont | 1:fdd22bb7aa52 | 244 | |
emilmont | 1:fdd22bb7aa52 | 245 | /* Calculate remaining number of copies */ |
emilmont | 1:fdd22bb7aa52 | 246 | tapCnt = (numStages) % 0x4u; |
emilmont | 1:fdd22bb7aa52 | 247 | |
emilmont | 1:fdd22bb7aa52 | 248 | /* Copy the remaining q31_t data */ |
emilmont | 1:fdd22bb7aa52 | 249 | while(tapCnt > 0u) |
emilmont | 1:fdd22bb7aa52 | 250 | { |
emilmont | 1:fdd22bb7aa52 | 251 | *pStateCurnt++ = *pState++; |
emilmont | 1:fdd22bb7aa52 | 252 | |
emilmont | 1:fdd22bb7aa52 | 253 | /* Decrement the loop counter */ |
emilmont | 1:fdd22bb7aa52 | 254 | tapCnt--; |
emilmont | 1:fdd22bb7aa52 | 255 | }; |
emilmont | 1:fdd22bb7aa52 | 256 | |
emilmont | 1:fdd22bb7aa52 | 257 | #else |
emilmont | 1:fdd22bb7aa52 | 258 | |
emilmont | 1:fdd22bb7aa52 | 259 | /* Run the below code for Cortex-M0 */ |
emilmont | 1:fdd22bb7aa52 | 260 | /* Sample processing */ |
emilmont | 1:fdd22bb7aa52 | 261 | while(blkCnt > 0u) |
emilmont | 1:fdd22bb7aa52 | 262 | { |
emilmont | 1:fdd22bb7aa52 | 263 | /* Read Sample from input buffer */ |
emilmont | 1:fdd22bb7aa52 | 264 | /* fN(n) = x(n) */ |
emilmont | 1:fdd22bb7aa52 | 265 | fcurr = *pSrc++; |
emilmont | 1:fdd22bb7aa52 | 266 | |
emilmont | 1:fdd22bb7aa52 | 267 | /* Initialize state read pointer */ |
emilmont | 1:fdd22bb7aa52 | 268 | px1 = pState; |
emilmont | 1:fdd22bb7aa52 | 269 | /* Initialize state write pointer */ |
emilmont | 1:fdd22bb7aa52 | 270 | px2 = pState; |
emilmont | 1:fdd22bb7aa52 | 271 | /* Set accumulator to zero */ |
emilmont | 1:fdd22bb7aa52 | 272 | acc = 0; |
emilmont | 1:fdd22bb7aa52 | 273 | /* Initialize Ladder coeff pointer */ |
emilmont | 1:fdd22bb7aa52 | 274 | pv = &S->pvCoeffs[0]; |
emilmont | 1:fdd22bb7aa52 | 275 | /* Initialize Reflection coeff pointer */ |
emilmont | 1:fdd22bb7aa52 | 276 | pk = &S->pkCoeffs[0]; |
emilmont | 1:fdd22bb7aa52 | 277 | |
emilmont | 1:fdd22bb7aa52 | 278 | tapCnt = numStages; |
emilmont | 1:fdd22bb7aa52 | 279 | |
emilmont | 1:fdd22bb7aa52 | 280 | while(tapCnt > 0u) |
emilmont | 1:fdd22bb7aa52 | 281 | { |
emilmont | 1:fdd22bb7aa52 | 282 | gcurr = *px1++; |
emilmont | 1:fdd22bb7aa52 | 283 | /* Process sample */ |
emilmont | 1:fdd22bb7aa52 | 284 | /* fN-1(n) = fN(n) - kN * gN-1(n-1) */ |
emilmont | 1:fdd22bb7aa52 | 285 | fnext = |
emilmont | 1:fdd22bb7aa52 | 286 | clip_q63_to_q31(((q63_t) fcurr - |
emilmont | 1:fdd22bb7aa52 | 287 | ((q31_t) (((q63_t) gcurr * (*pk)) >> 31)))); |
emilmont | 1:fdd22bb7aa52 | 288 | /* gN(n) = kN * fN-1(n) + gN-1(n-1) */ |
emilmont | 1:fdd22bb7aa52 | 289 | gnext = |
emilmont | 1:fdd22bb7aa52 | 290 | clip_q63_to_q31(((q63_t) gcurr + |
emilmont | 1:fdd22bb7aa52 | 291 | ((q31_t) (((q63_t) fnext * (*pk++)) >> 31)))); |
emilmont | 1:fdd22bb7aa52 | 292 | /* Output samples */ |
emilmont | 1:fdd22bb7aa52 | 293 | /* y(n) += gN(n) * vN */ |
emilmont | 1:fdd22bb7aa52 | 294 | acc += ((q63_t) gnext * *pv++); |
emilmont | 1:fdd22bb7aa52 | 295 | /* write gN-1(n-1) into state for next sample processing */ |
emilmont | 1:fdd22bb7aa52 | 296 | *px2++ = gnext; |
emilmont | 1:fdd22bb7aa52 | 297 | /* Update f values for next coefficient processing */ |
emilmont | 1:fdd22bb7aa52 | 298 | fcurr = fnext; |
emilmont | 1:fdd22bb7aa52 | 299 | |
emilmont | 1:fdd22bb7aa52 | 300 | tapCnt--; |
emilmont | 1:fdd22bb7aa52 | 301 | } |
emilmont | 1:fdd22bb7aa52 | 302 | |
emilmont | 1:fdd22bb7aa52 | 303 | /* y(n) += g0(n) * v0 */ |
emilmont | 1:fdd22bb7aa52 | 304 | acc += (q63_t) fnext *( |
emilmont | 1:fdd22bb7aa52 | 305 | *pv++); |
emilmont | 1:fdd22bb7aa52 | 306 | |
emilmont | 1:fdd22bb7aa52 | 307 | *px2++ = fnext; |
emilmont | 1:fdd22bb7aa52 | 308 | |
emilmont | 1:fdd22bb7aa52 | 309 | /* write out into pDst */ |
emilmont | 1:fdd22bb7aa52 | 310 | *pDst++ = (q31_t) (acc >> 31u); |
emilmont | 1:fdd22bb7aa52 | 311 | |
emilmont | 1:fdd22bb7aa52 | 312 | /* Advance the state pointer by 1 to process the next group of samples */ |
emilmont | 1:fdd22bb7aa52 | 313 | pState = pState + 1u; |
emilmont | 1:fdd22bb7aa52 | 314 | blkCnt--; |
emilmont | 1:fdd22bb7aa52 | 315 | |
emilmont | 1:fdd22bb7aa52 | 316 | } |
emilmont | 1:fdd22bb7aa52 | 317 | |
emilmont | 1:fdd22bb7aa52 | 318 | /* Processing is complete. Now copy last S->numStages samples to start of the buffer |
emilmont | 1:fdd22bb7aa52 | 319 | for the preperation of next frame process */ |
emilmont | 1:fdd22bb7aa52 | 320 | |
emilmont | 1:fdd22bb7aa52 | 321 | /* Points to the start of the state buffer */ |
emilmont | 1:fdd22bb7aa52 | 322 | pStateCurnt = &S->pState[0]; |
emilmont | 1:fdd22bb7aa52 | 323 | pState = &S->pState[blockSize]; |
emilmont | 1:fdd22bb7aa52 | 324 | |
emilmont | 1:fdd22bb7aa52 | 325 | tapCnt = numStages; |
emilmont | 1:fdd22bb7aa52 | 326 | |
emilmont | 1:fdd22bb7aa52 | 327 | /* Copy the remaining q31_t data */ |
emilmont | 1:fdd22bb7aa52 | 328 | while(tapCnt > 0u) |
emilmont | 1:fdd22bb7aa52 | 329 | { |
emilmont | 1:fdd22bb7aa52 | 330 | *pStateCurnt++ = *pState++; |
emilmont | 1:fdd22bb7aa52 | 331 | |
emilmont | 1:fdd22bb7aa52 | 332 | /* Decrement the loop counter */ |
emilmont | 1:fdd22bb7aa52 | 333 | tapCnt--; |
emilmont | 1:fdd22bb7aa52 | 334 | } |
emilmont | 1:fdd22bb7aa52 | 335 | |
emilmont | 1:fdd22bb7aa52 | 336 | #endif /* #ifndef ARM_MATH_CM0 */ |
emilmont | 1:fdd22bb7aa52 | 337 | |
emilmont | 1:fdd22bb7aa52 | 338 | } |
emilmont | 1:fdd22bb7aa52 | 339 | |
emilmont | 1:fdd22bb7aa52 | 340 | |
emilmont | 1:fdd22bb7aa52 | 341 | |
emilmont | 1:fdd22bb7aa52 | 342 | |
emilmont | 1:fdd22bb7aa52 | 343 | /** |
emilmont | 1:fdd22bb7aa52 | 344 | * @} end of IIR_Lattice group |
emilmont | 1:fdd22bb7aa52 | 345 | */ |