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CMSIS DSP library

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cmsis_dsp/TransformFunctions/arm_rfft_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?

UserRevisionLine numberNew 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_rfft_q31.c
emilmont 1:fdd22bb7aa52 9 *
emilmont 1:fdd22bb7aa52 10 * Description: RFFT & RIFFT Q31 process function
emilmont 1:fdd22bb7aa52 11 *
emilmont 1:fdd22bb7aa52 12 *
emilmont 1:fdd22bb7aa52 13 * Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
emilmont 1:fdd22bb7aa52 14 *
emilmont 1:fdd22bb7aa52 15 * Version 1.1.0 2012/02/15
emilmont 1:fdd22bb7aa52 16 * Updated with more optimizations, bug fixes and minor API changes.
emilmont 1:fdd22bb7aa52 17 *
emilmont 1:fdd22bb7aa52 18 * Version 1.0.10 2011/7/15
emilmont 1:fdd22bb7aa52 19 * Big Endian support added and Merged M0 and M3/M4 Source code.
emilmont 1:fdd22bb7aa52 20 *
emilmont 1:fdd22bb7aa52 21 * Version 1.0.3 2010/11/29
emilmont 1:fdd22bb7aa52 22 * Re-organized the CMSIS folders and updated documentation.
emilmont 1:fdd22bb7aa52 23 *
emilmont 1:fdd22bb7aa52 24 * Version 1.0.2 2010/11/11
emilmont 1:fdd22bb7aa52 25 * Documentation updated.
emilmont 1:fdd22bb7aa52 26 *
emilmont 1:fdd22bb7aa52 27 * Version 1.0.1 2010/10/05
emilmont 1:fdd22bb7aa52 28 * Production release and review comments incorporated.
emilmont 1:fdd22bb7aa52 29 *
emilmont 1:fdd22bb7aa52 30 * Version 1.0.0 2010/09/20
emilmont 1:fdd22bb7aa52 31 * Production release and review comments incorporated.
emilmont 1:fdd22bb7aa52 32 *
emilmont 1:fdd22bb7aa52 33 * Version 0.0.7 2010/06/10
emilmont 1:fdd22bb7aa52 34 * Misra-C changes done
emilmont 1:fdd22bb7aa52 35 * -------------------------------------------------------------------- */
emilmont 1:fdd22bb7aa52 36
emilmont 1:fdd22bb7aa52 37 #include "arm_math.h"
emilmont 1:fdd22bb7aa52 38
emilmont 1:fdd22bb7aa52 39 /*--------------------------------------------------------------------
emilmont 1:fdd22bb7aa52 40 * Internal functions prototypes
emilmont 1:fdd22bb7aa52 41 --------------------------------------------------------------------*/
emilmont 1:fdd22bb7aa52 42
emilmont 1:fdd22bb7aa52 43 void arm_split_rfft_q31(
emilmont 1:fdd22bb7aa52 44 q31_t * pSrc,
emilmont 1:fdd22bb7aa52 45 uint32_t fftLen,
emilmont 1:fdd22bb7aa52 46 q31_t * pATable,
emilmont 1:fdd22bb7aa52 47 q31_t * pBTable,
emilmont 1:fdd22bb7aa52 48 q31_t * pDst,
emilmont 1:fdd22bb7aa52 49 uint32_t modifier);
emilmont 1:fdd22bb7aa52 50
emilmont 1:fdd22bb7aa52 51 void arm_split_rifft_q31(
emilmont 1:fdd22bb7aa52 52 q31_t * pSrc,
emilmont 1:fdd22bb7aa52 53 uint32_t fftLen,
emilmont 1:fdd22bb7aa52 54 q31_t * pATable,
emilmont 1:fdd22bb7aa52 55 q31_t * pBTable,
emilmont 1:fdd22bb7aa52 56 q31_t * pDst,
emilmont 1:fdd22bb7aa52 57 uint32_t modifier);
emilmont 1:fdd22bb7aa52 58
emilmont 1:fdd22bb7aa52 59 /**
emilmont 1:fdd22bb7aa52 60 * @addtogroup RFFT_RIFFT
emilmont 1:fdd22bb7aa52 61 * @{
emilmont 1:fdd22bb7aa52 62 */
emilmont 1:fdd22bb7aa52 63
emilmont 1:fdd22bb7aa52 64 /**
emilmont 1:fdd22bb7aa52 65 * @brief Processing function for the Q31 RFFT/RIFFT.
emilmont 1:fdd22bb7aa52 66 * @param[in] *S points to an instance of the Q31 RFFT/RIFFT structure.
emilmont 1:fdd22bb7aa52 67 * @param[in] *pSrc points to the input buffer.
emilmont 1:fdd22bb7aa52 68 * @param[out] *pDst points to the output buffer.
emilmont 1:fdd22bb7aa52 69 * @return none.
emilmont 1:fdd22bb7aa52 70 *
emilmont 1:fdd22bb7aa52 71 * \par Input an output formats:
emilmont 1:fdd22bb7aa52 72 * \par
emilmont 1:fdd22bb7aa52 73 * Internally input is downscaled by 2 for every stage to avoid saturations inside CFFT/CIFFT process.
emilmont 1:fdd22bb7aa52 74 * Hence the output format is different for different RFFT sizes.
emilmont 1:fdd22bb7aa52 75 * The input and output formats for different RFFT sizes and number of bits to upscale are mentioned in the tables below for RFFT and RIFFT:
emilmont 1:fdd22bb7aa52 76 * \par
emilmont 1:fdd22bb7aa52 77 * \image html RFFTQ31.gif "Input and Output Formats for Q31 RFFT"
emilmont 1:fdd22bb7aa52 78 *
emilmont 1:fdd22bb7aa52 79 * \par
emilmont 1:fdd22bb7aa52 80 * \image html RIFFTQ31.gif "Input and Output Formats for Q31 RIFFT"
emilmont 1:fdd22bb7aa52 81 */
emilmont 1:fdd22bb7aa52 82
emilmont 1:fdd22bb7aa52 83 void arm_rfft_q31(
emilmont 1:fdd22bb7aa52 84 const arm_rfft_instance_q31 * S,
emilmont 1:fdd22bb7aa52 85 q31_t * pSrc,
emilmont 1:fdd22bb7aa52 86 q31_t * pDst)
emilmont 1:fdd22bb7aa52 87 {
emilmont 1:fdd22bb7aa52 88 const arm_cfft_radix4_instance_q31 *S_CFFT = S->pCfft;
emilmont 1:fdd22bb7aa52 89
emilmont 1:fdd22bb7aa52 90 /* Calculation of RIFFT of input */
emilmont 1:fdd22bb7aa52 91 if(S->ifftFlagR == 1u)
emilmont 1:fdd22bb7aa52 92 {
emilmont 1:fdd22bb7aa52 93 /* Real IFFT core process */
emilmont 1:fdd22bb7aa52 94 arm_split_rifft_q31(pSrc, S->fftLenBy2, S->pTwiddleAReal,
emilmont 1:fdd22bb7aa52 95 S->pTwiddleBReal, pDst, S->twidCoefRModifier);
emilmont 1:fdd22bb7aa52 96
emilmont 1:fdd22bb7aa52 97 /* Complex readix-4 IFFT process */
emilmont 1:fdd22bb7aa52 98 arm_radix4_butterfly_inverse_q31(pDst, S_CFFT->fftLen,
emilmont 1:fdd22bb7aa52 99 S_CFFT->pTwiddle,
emilmont 1:fdd22bb7aa52 100 S_CFFT->twidCoefModifier);
emilmont 1:fdd22bb7aa52 101 /* Bit reversal process */
emilmont 1:fdd22bb7aa52 102 if(S->bitReverseFlagR == 1u)
emilmont 1:fdd22bb7aa52 103 {
emilmont 1:fdd22bb7aa52 104 arm_bitreversal_q31(pDst, S_CFFT->fftLen,
emilmont 1:fdd22bb7aa52 105 S_CFFT->bitRevFactor, S_CFFT->pBitRevTable);
emilmont 1:fdd22bb7aa52 106 }
emilmont 1:fdd22bb7aa52 107 }
emilmont 1:fdd22bb7aa52 108 else
emilmont 1:fdd22bb7aa52 109 {
emilmont 1:fdd22bb7aa52 110 /* Calculation of RFFT of input */
emilmont 1:fdd22bb7aa52 111
emilmont 1:fdd22bb7aa52 112 /* Complex readix-4 FFT process */
emilmont 1:fdd22bb7aa52 113 arm_radix4_butterfly_q31(pSrc, S_CFFT->fftLen,
emilmont 1:fdd22bb7aa52 114 S_CFFT->pTwiddle, S_CFFT->twidCoefModifier);
emilmont 1:fdd22bb7aa52 115
emilmont 1:fdd22bb7aa52 116 /* Bit reversal process */
emilmont 1:fdd22bb7aa52 117 if(S->bitReverseFlagR == 1u)
emilmont 1:fdd22bb7aa52 118 {
emilmont 1:fdd22bb7aa52 119 arm_bitreversal_q31(pSrc, S_CFFT->fftLen,
emilmont 1:fdd22bb7aa52 120 S_CFFT->bitRevFactor, S_CFFT->pBitRevTable);
emilmont 1:fdd22bb7aa52 121 }
emilmont 1:fdd22bb7aa52 122
emilmont 1:fdd22bb7aa52 123 /* Real FFT core process */
emilmont 1:fdd22bb7aa52 124 arm_split_rfft_q31(pSrc, S->fftLenBy2, S->pTwiddleAReal,
emilmont 1:fdd22bb7aa52 125 S->pTwiddleBReal, pDst, S->twidCoefRModifier);
emilmont 1:fdd22bb7aa52 126 }
emilmont 1:fdd22bb7aa52 127
emilmont 1:fdd22bb7aa52 128 }
emilmont 1:fdd22bb7aa52 129
emilmont 1:fdd22bb7aa52 130
emilmont 1:fdd22bb7aa52 131 /**
emilmont 1:fdd22bb7aa52 132 * @} end of RFFT_RIFFT group
emilmont 1:fdd22bb7aa52 133 */
emilmont 1:fdd22bb7aa52 134
emilmont 1:fdd22bb7aa52 135 /**
emilmont 1:fdd22bb7aa52 136 * @brief Core Real FFT process
emilmont 1:fdd22bb7aa52 137 * @param[in] *pSrc points to the input buffer.
emilmont 1:fdd22bb7aa52 138 * @param[in] fftLen length of FFT.
emilmont 1:fdd22bb7aa52 139 * @param[in] *pATable points to the twiddle Coef A buffer.
emilmont 1:fdd22bb7aa52 140 * @param[in] *pBTable points to the twiddle Coef B buffer.
emilmont 1:fdd22bb7aa52 141 * @param[out] *pDst points to the output buffer.
emilmont 1:fdd22bb7aa52 142 * @param[in] modifier twiddle coefficient modifier that supports different size FFTs with the same twiddle factor table.
emilmont 1:fdd22bb7aa52 143 * @return none.
emilmont 1:fdd22bb7aa52 144 */
emilmont 1:fdd22bb7aa52 145
emilmont 1:fdd22bb7aa52 146 void arm_split_rfft_q31(
emilmont 1:fdd22bb7aa52 147 q31_t * pSrc,
emilmont 1:fdd22bb7aa52 148 uint32_t fftLen,
emilmont 1:fdd22bb7aa52 149 q31_t * pATable,
emilmont 1:fdd22bb7aa52 150 q31_t * pBTable,
emilmont 1:fdd22bb7aa52 151 q31_t * pDst,
emilmont 1:fdd22bb7aa52 152 uint32_t modifier)
emilmont 1:fdd22bb7aa52 153 {
emilmont 1:fdd22bb7aa52 154 uint32_t i; /* Loop Counter */
emilmont 1:fdd22bb7aa52 155 q31_t outR, outI; /* Temporary variables for output */
emilmont 1:fdd22bb7aa52 156 q31_t *pCoefA, *pCoefB; /* Temporary pointers for twiddle factors */
emilmont 1:fdd22bb7aa52 157 q31_t CoefA1, CoefA2, CoefB1; /* Temporary variables for twiddle coefficients */
emilmont 1:fdd22bb7aa52 158 q31_t *pOut1 = &pDst[2], *pOut2 = &pDst[(4u * fftLen) - 1u];
emilmont 1:fdd22bb7aa52 159 q31_t *pIn1 = &pSrc[2], *pIn2 = &pSrc[(2u * fftLen) - 1u];
emilmont 1:fdd22bb7aa52 160
emilmont 1:fdd22bb7aa52 161 /* Init coefficient pointers */
emilmont 1:fdd22bb7aa52 162 pCoefA = &pATable[modifier * 2u];
emilmont 1:fdd22bb7aa52 163 pCoefB = &pBTable[modifier * 2u];
emilmont 1:fdd22bb7aa52 164
emilmont 1:fdd22bb7aa52 165 i = fftLen - 1u;
emilmont 1:fdd22bb7aa52 166
emilmont 1:fdd22bb7aa52 167 while(i > 0u)
emilmont 1:fdd22bb7aa52 168 {
emilmont 1:fdd22bb7aa52 169 /*
emilmont 1:fdd22bb7aa52 170 outR = (pSrc[2 * i] * pATable[2 * i] - pSrc[2 * i + 1] * pATable[2 * i + 1]
emilmont 1:fdd22bb7aa52 171 + pSrc[2 * n - 2 * i] * pBTable[2 * i] +
emilmont 1:fdd22bb7aa52 172 pSrc[2 * n - 2 * i + 1] * pBTable[2 * i + 1]);
emilmont 1:fdd22bb7aa52 173 */
emilmont 1:fdd22bb7aa52 174
emilmont 1:fdd22bb7aa52 175 /* outI = (pIn[2 * i + 1] * pATable[2 * i] + pIn[2 * i] * pATable[2 * i + 1] +
emilmont 1:fdd22bb7aa52 176 pIn[2 * n - 2 * i] * pBTable[2 * i + 1] -
emilmont 1:fdd22bb7aa52 177 pIn[2 * n - 2 * i + 1] * pBTable[2 * i]); */
emilmont 1:fdd22bb7aa52 178
emilmont 1:fdd22bb7aa52 179 CoefA1 = *pCoefA++;
emilmont 1:fdd22bb7aa52 180 CoefA2 = *pCoefA;
emilmont 1:fdd22bb7aa52 181
emilmont 1:fdd22bb7aa52 182 /* outR = (pSrc[2 * i] * pATable[2 * i] */
emilmont 1:fdd22bb7aa52 183 outR = ((int32_t) (((q63_t) * pIn1 * CoefA1) >> 32));
emilmont 1:fdd22bb7aa52 184
emilmont 1:fdd22bb7aa52 185 /* outI = pIn[2 * i] * pATable[2 * i + 1] */
emilmont 1:fdd22bb7aa52 186 outI = ((int32_t) (((q63_t) * pIn1++ * CoefA2) >> 32));
emilmont 1:fdd22bb7aa52 187
emilmont 1:fdd22bb7aa52 188 /* - pSrc[2 * i + 1] * pATable[2 * i + 1] */
emilmont 1:fdd22bb7aa52 189 outR =
emilmont 1:fdd22bb7aa52 190 (q31_t) ((((q63_t) outR << 32) + ((q63_t) * pIn1 * (-CoefA2))) >> 32);
emilmont 1:fdd22bb7aa52 191
emilmont 1:fdd22bb7aa52 192 /* (pIn[2 * i + 1] * pATable[2 * i] */
emilmont 1:fdd22bb7aa52 193 outI =
emilmont 1:fdd22bb7aa52 194 (q31_t) ((((q63_t) outI << 32) + ((q63_t) * pIn1++ * (CoefA1))) >> 32);
emilmont 1:fdd22bb7aa52 195
emilmont 1:fdd22bb7aa52 196 /* pSrc[2 * n - 2 * i] * pBTable[2 * i] */
emilmont 1:fdd22bb7aa52 197 outR =
emilmont 1:fdd22bb7aa52 198 (q31_t) ((((q63_t) outR << 32) + ((q63_t) * pIn2 * (-CoefA2))) >> 32);
emilmont 1:fdd22bb7aa52 199 CoefB1 = *pCoefB;
emilmont 1:fdd22bb7aa52 200
emilmont 1:fdd22bb7aa52 201 /* pIn[2 * n - 2 * i] * pBTable[2 * i + 1] */
emilmont 1:fdd22bb7aa52 202 outI =
emilmont 1:fdd22bb7aa52 203 (q31_t) ((((q63_t) outI << 32) + ((q63_t) * pIn2-- * (-CoefB1))) >> 32);
emilmont 1:fdd22bb7aa52 204
emilmont 1:fdd22bb7aa52 205 /* pSrc[2 * n - 2 * i + 1] * pBTable[2 * i + 1] */
emilmont 1:fdd22bb7aa52 206 outR =
emilmont 1:fdd22bb7aa52 207 (q31_t) ((((q63_t) outR << 32) + ((q63_t) * pIn2 * (CoefB1))) >> 32);
emilmont 1:fdd22bb7aa52 208
emilmont 1:fdd22bb7aa52 209 /* pIn[2 * n - 2 * i + 1] * pBTable[2 * i] */
emilmont 1:fdd22bb7aa52 210 outI =
emilmont 1:fdd22bb7aa52 211 (q31_t) ((((q63_t) outI << 32) + ((q63_t) * pIn2-- * (-CoefA2))) >> 32);
emilmont 1:fdd22bb7aa52 212
emilmont 1:fdd22bb7aa52 213 /* write output */
emilmont 1:fdd22bb7aa52 214 *pOut1++ = (outR << 1u);
emilmont 1:fdd22bb7aa52 215 *pOut1++ = (outI << 1u);
emilmont 1:fdd22bb7aa52 216
emilmont 1:fdd22bb7aa52 217 /* write complex conjugate output */
emilmont 1:fdd22bb7aa52 218 *pOut2-- = -(outI << 1u);
emilmont 1:fdd22bb7aa52 219 *pOut2-- = (outR << 1u);
emilmont 1:fdd22bb7aa52 220
emilmont 1:fdd22bb7aa52 221 /* update coefficient pointer */
emilmont 1:fdd22bb7aa52 222 pCoefB = pCoefB + (modifier * 2u);
emilmont 1:fdd22bb7aa52 223 pCoefA = pCoefA + ((modifier * 2u) - 1u);
emilmont 1:fdd22bb7aa52 224
emilmont 1:fdd22bb7aa52 225 i--;
emilmont 1:fdd22bb7aa52 226
emilmont 1:fdd22bb7aa52 227 }
emilmont 1:fdd22bb7aa52 228
emilmont 1:fdd22bb7aa52 229 pDst[2u * fftLen] = pSrc[0] - pSrc[1];
emilmont 1:fdd22bb7aa52 230 pDst[(2u * fftLen) + 1u] = 0;
emilmont 1:fdd22bb7aa52 231
emilmont 1:fdd22bb7aa52 232 pDst[0] = pSrc[0] + pSrc[1];
emilmont 1:fdd22bb7aa52 233 pDst[1] = 0;
emilmont 1:fdd22bb7aa52 234
emilmont 1:fdd22bb7aa52 235 }
emilmont 1:fdd22bb7aa52 236
emilmont 1:fdd22bb7aa52 237
emilmont 1:fdd22bb7aa52 238 /**
emilmont 1:fdd22bb7aa52 239 * @brief Core Real IFFT process
emilmont 1:fdd22bb7aa52 240 * @param[in] *pSrc points to the input buffer.
emilmont 1:fdd22bb7aa52 241 * @param[in] fftLen length of FFT.
emilmont 1:fdd22bb7aa52 242 * @param[in] *pATable points to the twiddle Coef A buffer.
emilmont 1:fdd22bb7aa52 243 * @param[in] *pBTable points to the twiddle Coef B buffer.
emilmont 1:fdd22bb7aa52 244 * @param[out] *pDst points to the output buffer.
emilmont 1:fdd22bb7aa52 245 * @param[in] modifier twiddle coefficient modifier that supports different size FFTs with the same twiddle factor table.
emilmont 1:fdd22bb7aa52 246 * @return none.
emilmont 1:fdd22bb7aa52 247 */
emilmont 1:fdd22bb7aa52 248
emilmont 1:fdd22bb7aa52 249 void arm_split_rifft_q31(
emilmont 1:fdd22bb7aa52 250 q31_t * pSrc,
emilmont 1:fdd22bb7aa52 251 uint32_t fftLen,
emilmont 1:fdd22bb7aa52 252 q31_t * pATable,
emilmont 1:fdd22bb7aa52 253 q31_t * pBTable,
emilmont 1:fdd22bb7aa52 254 q31_t * pDst,
emilmont 1:fdd22bb7aa52 255 uint32_t modifier)
emilmont 1:fdd22bb7aa52 256 {
emilmont 1:fdd22bb7aa52 257 q31_t outR, outI; /* Temporary variables for output */
emilmont 1:fdd22bb7aa52 258 q31_t *pCoefA, *pCoefB; /* Temporary pointers for twiddle factors */
emilmont 1:fdd22bb7aa52 259 q31_t CoefA1, CoefA2, CoefB1; /* Temporary variables for twiddle coefficients */
emilmont 1:fdd22bb7aa52 260 q31_t *pIn1 = &pSrc[0], *pIn2 = &pSrc[(2u * fftLen) + 1u];
emilmont 1:fdd22bb7aa52 261
emilmont 1:fdd22bb7aa52 262 pCoefA = &pATable[0];
emilmont 1:fdd22bb7aa52 263 pCoefB = &pBTable[0];
emilmont 1:fdd22bb7aa52 264
emilmont 1:fdd22bb7aa52 265 while(fftLen > 0u)
emilmont 1:fdd22bb7aa52 266 {
emilmont 1:fdd22bb7aa52 267 /*
emilmont 1:fdd22bb7aa52 268 outR = (pIn[2 * i] * pATable[2 * i] + pIn[2 * i + 1] * pATable[2 * i + 1] +
emilmont 1:fdd22bb7aa52 269 pIn[2 * n - 2 * i] * pBTable[2 * i] -
emilmont 1:fdd22bb7aa52 270 pIn[2 * n - 2 * i + 1] * pBTable[2 * i + 1]);
emilmont 1:fdd22bb7aa52 271
emilmont 1:fdd22bb7aa52 272 outI = (pIn[2 * i + 1] * pATable[2 * i] - pIn[2 * i] * pATable[2 * i + 1] -
emilmont 1:fdd22bb7aa52 273 pIn[2 * n - 2 * i] * pBTable[2 * i + 1] -
emilmont 1:fdd22bb7aa52 274 pIn[2 * n - 2 * i + 1] * pBTable[2 * i]);
emilmont 1:fdd22bb7aa52 275
emilmont 1:fdd22bb7aa52 276 */
emilmont 1:fdd22bb7aa52 277 CoefA1 = *pCoefA++;
emilmont 1:fdd22bb7aa52 278 CoefA2 = *pCoefA;
emilmont 1:fdd22bb7aa52 279
emilmont 1:fdd22bb7aa52 280 /* outR = (pIn[2 * i] * pATable[2 * i] */
emilmont 1:fdd22bb7aa52 281 outR = ((int32_t) (((q63_t) * pIn1 * CoefA1) >> 32));
emilmont 1:fdd22bb7aa52 282
emilmont 1:fdd22bb7aa52 283 /* - pIn[2 * i] * pATable[2 * i + 1] */
emilmont 1:fdd22bb7aa52 284 outI = -((int32_t) (((q63_t) * pIn1++ * CoefA2) >> 32));
emilmont 1:fdd22bb7aa52 285
emilmont 1:fdd22bb7aa52 286 /* pIn[2 * i + 1] * pATable[2 * i + 1] */
emilmont 1:fdd22bb7aa52 287 outR =
emilmont 1:fdd22bb7aa52 288 (q31_t) ((((q63_t) outR << 32) + ((q63_t) * pIn1 * (CoefA2))) >> 32);
emilmont 1:fdd22bb7aa52 289
emilmont 1:fdd22bb7aa52 290 /* pIn[2 * i + 1] * pATable[2 * i] */
emilmont 1:fdd22bb7aa52 291 outI =
emilmont 1:fdd22bb7aa52 292 (q31_t) ((((q63_t) outI << 32) + ((q63_t) * pIn1++ * (CoefA1))) >> 32);
emilmont 1:fdd22bb7aa52 293
emilmont 1:fdd22bb7aa52 294 /* pIn[2 * n - 2 * i] * pBTable[2 * i] */
emilmont 1:fdd22bb7aa52 295 outR =
emilmont 1:fdd22bb7aa52 296 (q31_t) ((((q63_t) outR << 32) + ((q63_t) * pIn2 * (CoefA2))) >> 32);
emilmont 1:fdd22bb7aa52 297
emilmont 1:fdd22bb7aa52 298 CoefB1 = *pCoefB;
emilmont 1:fdd22bb7aa52 299
emilmont 1:fdd22bb7aa52 300 /* pIn[2 * n - 2 * i] * pBTable[2 * i + 1] */
emilmont 1:fdd22bb7aa52 301 outI =
emilmont 1:fdd22bb7aa52 302 (q31_t) ((((q63_t) outI << 32) - ((q63_t) * pIn2-- * (CoefB1))) >> 32);
emilmont 1:fdd22bb7aa52 303
emilmont 1:fdd22bb7aa52 304 /* pIn[2 * n - 2 * i + 1] * pBTable[2 * i + 1] */
emilmont 1:fdd22bb7aa52 305 outR =
emilmont 1:fdd22bb7aa52 306 (q31_t) ((((q63_t) outR << 32) + ((q63_t) * pIn2 * (CoefB1))) >> 32);
emilmont 1:fdd22bb7aa52 307
emilmont 1:fdd22bb7aa52 308 /* pIn[2 * n - 2 * i + 1] * pBTable[2 * i] */
emilmont 1:fdd22bb7aa52 309 outI =
emilmont 1:fdd22bb7aa52 310 (q31_t) ((((q63_t) outI << 32) + ((q63_t) * pIn2-- * (CoefA2))) >> 32);
emilmont 1:fdd22bb7aa52 311
emilmont 1:fdd22bb7aa52 312 /* write output */
emilmont 1:fdd22bb7aa52 313 *pDst++ = (outR << 1u);
emilmont 1:fdd22bb7aa52 314 *pDst++ = (outI << 1u);
emilmont 1:fdd22bb7aa52 315
emilmont 1:fdd22bb7aa52 316 /* update coefficient pointer */
emilmont 1:fdd22bb7aa52 317 pCoefB = pCoefB + (modifier * 2u);
emilmont 1:fdd22bb7aa52 318 pCoefA = pCoefA + ((modifier * 2u) - 1u);
emilmont 1:fdd22bb7aa52 319
emilmont 1:fdd22bb7aa52 320 /* Decrement loop count */
emilmont 1:fdd22bb7aa52 321 fftLen--;
emilmont 1:fdd22bb7aa52 322
emilmont 1:fdd22bb7aa52 323 }
emilmont 1:fdd22bb7aa52 324
emilmont 1:fdd22bb7aa52 325
emilmont 1:fdd22bb7aa52 326 }