arm_rfft_q31.c
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00001 /* ---------------------------------------------------------------------- 00002 * Copyright (C) 2011 ARM Limited. All rights reserved. 00003 * 00004 * $Date: 15. December 2011 00005 * $Revision: V2.0.0 00006 * 00007 * Project: Cortex-R DSP Library 00008 * Title: arm_rfft_q31.c 00009 * 00010 * Description: RFFT & RIFFT Q31 process function 00011 * 00012 * Target Processor: Cortex-R4/R5 00013 * 00014 * Version 1.0.0 2011/03/08 00015 * Alpha release. 00016 * 00017 * Version 1.0.1 2011/09/30 00018 * Beta release. 00019 * 00020 * Version 2.0.0 2011/12/15 00021 * Final release. 00022 * 00023 * -------------------------------------------------------------------- */ 00024 #include "arm_math.h" 00025 00026 /*-------------------------------------------------------------------- 00027 * Internal functions prototypes 00028 --------------------------------------------------------------------*/ 00029 00030 void arm_split_rfft_q31( 00031 q31_t * pSrc, 00032 uint32_t fftLen, 00033 q31_t * pATable, 00034 q31_t * pBTable, 00035 q31_t * pDst, 00036 uint32_t modifier); 00037 00038 void arm_split_rifft_q31( 00039 q31_t * pSrc, 00040 uint32_t fftLen, 00041 q31_t * pATable, 00042 q31_t * pBTable, 00043 q31_t * pDst, 00044 uint32_t modifier); 00045 00070 void arm_rfft_q31( 00071 const arm_rfft_instance_q31 * S, 00072 q31_t * pSrc, 00073 q31_t * pDst) 00074 { 00075 const arm_cfft_radix4_instance_q31 *S_CFFT = S->pCfft; 00076 00077 /* Calculation of RIFFT of input */ 00078 if(S->ifftFlagR == 1u) 00079 { 00080 /* Real IFFT core process */ 00081 arm_split_rifft_q31(pSrc, S->fftLenBy2, S->pTwiddleAReal, 00082 S->pTwiddleBReal, pDst, S->twidCoefRModifier); 00083 00084 /* Complex readix-4 IFFT process */ 00085 arm_radix4_butterfly_inverse_q31(pDst, S_CFFT->fftLen, 00086 S_CFFT->pTwiddle, 00087 S_CFFT->twidCoefModifier); 00088 /* Bit reversal process */ 00089 if(S->bitReverseFlagR == 1u) 00090 { 00091 arm_bitreversal_q31(pDst, S_CFFT->fftLen, 00092 S_CFFT->bitRevFactor, S_CFFT->pBitRevTable); 00093 } 00094 } 00095 else 00096 { 00097 /* Calculation of RFFT of input */ 00098 00099 /* Complex readix-4 FFT process */ 00100 arm_radix4_butterfly_q31(pSrc, S_CFFT->fftLen, 00101 S_CFFT->pTwiddle, S_CFFT->twidCoefModifier); 00102 00103 /* Bit reversal process */ 00104 if(S->bitReverseFlagR == 1u) 00105 { 00106 arm_bitreversal_q31(pSrc, S_CFFT->fftLen, 00107 S_CFFT->bitRevFactor, S_CFFT->pBitRevTable); 00108 } 00109 00110 /* Real FFT core process */ 00111 arm_split_rfft_q31(pSrc, S->fftLenBy2, S->pTwiddleAReal, 00112 S->pTwiddleBReal, pDst, S->twidCoefRModifier); 00113 } 00114 00115 } 00116 00117 00133 void arm_split_rfft_q31( 00134 q31_t * pSrc, 00135 uint32_t fftLen, 00136 q31_t * pATable, 00137 q31_t * pBTable, 00138 q31_t * pDst, 00139 uint32_t modifier) 00140 { 00141 uint32_t i; /* Loop Counter */ 00142 q31_t inVal1, inVal2; 00143 q31_t outR, outI; /* Temporary variables for output */ 00144 q31_t *pCoefA, *pCoefB; /* Temporary pointers for twiddle factors */ 00145 q31_t CoefA1, CoefA2, CoefB1; /* Temporary variables for twiddle coefficients */ 00146 q31_t *pOut1 = &pDst[2], *pOut2 = &pDst[(4u * fftLen) - 1u]; 00147 q31_t *pIn1 = &pSrc[2], *pIn2 = &pSrc[(2u * fftLen) - 1u]; 00148 00149 /* Init coefficient pointers */ 00150 pCoefA = &pATable[modifier * 2u]; 00151 pCoefB = &pBTable[modifier * 2u]; 00152 00153 i = fftLen - 1u; 00154 00155 while(i > 0u) 00156 { 00157 /* 00158 outR = (pSrc[2 * i] * pATable[2 * i] - pSrc[2 * i + 1] * pATable[2 * i + 1] 00159 + pSrc[2 * n - 2 * i] * pBTable[2 * i] + 00160 pSrc[2 * n - 2 * i + 1] * pBTable[2 * i + 1]); 00161 */ 00162 00163 /* outI = (pIn[2 * i + 1] * pATable[2 * i] + pIn[2 * i] * pATable[2 * i + 1] + 00164 pIn[2 * n - 2 * i] * pBTable[2 * i + 1] - 00165 pIn[2 * n - 2 * i + 1] * pBTable[2 * i]); */ 00166 00167 CoefA1 = pCoefA[0]; 00168 00169 inVal1 = pIn1[0]; 00170 pIn2 -= 2u; 00171 00172 CoefA2 = pCoefA[1]; 00173 00174 /* outR = (pSrc[2 * i] * pATable[2 * i] */ 00175 outR = ((int32_t) (((q63_t) inVal1 * CoefA1) >> 32)); 00176 00177 inVal2 = pIn1[1]; 00178 00179 /* outI = pIn[2 * i] * pATable[2 * i + 1] */ 00180 outI = ((int32_t) (((q63_t) inVal1 * CoefA2) >> 32)); 00181 00182 /* - pSrc[2 * i + 1] * pATable[2 * i + 1] */ 00183 outR = 00184 (q31_t) ((((q63_t) outR << 32) + ((q63_t) inVal2 * (-CoefA2))) >> 32); 00185 00186 inVal1 = pIn2[2]; 00187 pIn1 += 2u; 00188 00189 /* (pIn[2 * i + 1] * pATable[2 * i] */ 00190 outI = 00191 (q31_t) ((((q63_t) outI << 32) + ((q63_t) inVal2 * (CoefA1))) >> 32); 00192 00193 /* pSrc[2 * n - 2 * i] * pBTable[2 * i] */ 00194 outR = 00195 (q31_t) ((((q63_t) outR << 32) + ((q63_t) inVal1 * (-CoefA2))) >> 32); 00196 00197 CoefB1 = *pCoefB; 00198 00199 inVal2 = pIn2[1]; 00200 00201 /* pIn[2 * n - 2 * i] * pBTable[2 * i + 1] */ 00202 outI = 00203 (q31_t) ((((q63_t) outI << 32) - ((q63_t) inVal1 * (CoefB1))) >> 32); 00204 00205 00206 /* pSrc[2 * n - 2 * i + 1] * pBTable[2 * i + 1] */ 00207 outR = 00208 (q31_t) ((((q63_t) outR << 32) + ((q63_t) inVal2 * (CoefB1))) >> 32); 00209 00210 /* pIn[2 * n - 2 * i + 1] * pBTable[2 * i] */ 00211 outI = 00212 (q31_t) ((((q63_t) outI << 32) - ((q63_t) inVal2 * (CoefA2))) >> 32); 00213 00214 pOut2 -= 2u; 00215 00216 /* write output */ 00217 *pOut1++ = (outR << 1u); 00218 *pOut1++ = (outI << 1u); 00219 00220 /* write complex conjugate output */ 00221 pOut2[2] = -(outI << 1u); 00222 pOut2[1] = (outR << 1u); 00223 00224 /* update coefficient pointer */ 00225 pCoefB = pCoefB + (modifier * 2u); 00226 pCoefA = pCoefA + (modifier * 2u); 00227 00228 i--; 00229 00230 } 00231 00232 pDst[2u * fftLen] = pSrc[0] - pSrc[1]; 00233 pDst[(2u * fftLen) + 1u] = 0; 00234 00235 pDst[0] = pSrc[0] + pSrc[1]; 00236 pDst[1] = 0; 00237 00238 } 00239 00240 00252 void arm_split_rifft_q31( 00253 q31_t * pSrc, 00254 uint32_t fftLen, 00255 q31_t * pATable, 00256 q31_t * pBTable, 00257 q31_t * pDst, 00258 uint32_t modifier) 00259 { 00260 q31_t inVal1, inVal2; 00261 q31_t outR, outI; /* Temporary variables for output */ 00262 q31_t *pCoefA, *pCoefB; /* Temporary pointers for twiddle factors */ 00263 q31_t CoefA1, CoefA2, CoefB1; /* Temporary variables for twiddle coefficients */ 00264 q31_t *pIn1 = &pSrc[0], *pIn2 = &pSrc[(2u * fftLen) + 1u]; 00265 00266 pCoefA = &pATable[0]; 00267 pCoefB = &pBTable[0]; 00268 00269 while(fftLen > 0u) 00270 { 00271 /* 00272 outR = (pIn[2 * i] * pATable[2 * i] + pIn[2 * i + 1] * pATable[2 * i + 1] + 00273 pIn[2 * n - 2 * i] * pBTable[2 * i] - 00274 pIn[2 * n - 2 * i + 1] * pBTable[2 * i + 1]); 00275 00276 outI = (pIn[2 * i + 1] * pATable[2 * i] - pIn[2 * i] * pATable[2 * i + 1] - 00277 pIn[2 * n - 2 * i] * pBTable[2 * i + 1] - 00278 pIn[2 * n - 2 * i + 1] * pBTable[2 * i]); 00279 00280 */ 00281 inVal1 = *pIn1; 00282 pIn2 -= 2u; 00283 00284 CoefA1 = *pCoefA++; 00285 CoefA2 = *pCoefA; 00286 00287 /* outR = (pIn[2 * i] * pATable[2 * i] */ 00288 outR = ((int32_t) (((q63_t) inVal1 * CoefA1) >> 32)); 00289 00290 inVal2 = pIn1[1]; 00291 00292 pIn1 += 2u; 00293 00294 /* - pIn[2 * i] * pATable[2 * i + 1] */ 00295 outI = -((int32_t) (((q63_t) inVal1 * CoefA2) >> 32)); 00296 00297 inVal1 = pIn2[2]; 00298 00299 /* pIn[2 * i + 1] * pATable[2 * i + 1] */ 00300 outR = 00301 (q31_t) ((((q63_t) outR << 32) + ((q63_t) inVal2 * (CoefA2))) >> 32); 00302 00303 00304 /* pIn[2 * i + 1] * pATable[2 * i] */ 00305 outI = 00306 (q31_t) ((((q63_t) outI << 32) + ((q63_t) inVal2* (CoefA1))) >> 32); 00307 00308 00309 /* pIn[2 * n - 2 * i] * pBTable[2 * i] */ 00310 outR = 00311 (q31_t) ((((q63_t) outR << 32) + ((q63_t) inVal1 * (CoefA2))) >> 32); 00312 00313 CoefB1 = *pCoefB; 00314 00315 00316 inVal2 = pIn2[1]; 00317 00318 /* pIn[2 * n - 2 * i] * pBTable[2 * i + 1] */ 00319 outI = 00320 (q31_t) ((((q63_t) outI << 32) - ((q63_t) inVal1 * (CoefB1))) >> 32); 00321 00322 /* pIn[2 * n - 2 * i + 1] * pBTable[2 * i + 1] */ 00323 outR = 00324 (q31_t) ((((q63_t) outR << 32) + ((q63_t) inVal2 * (CoefB1))) >> 32); 00325 00326 00327 /* pIn[2 * n - 2 * i + 1] * pBTable[2 * i] */ 00328 outI = 00329 (q31_t) ((((q63_t) outI << 32) + ((q63_t) inVal2 * (CoefA2))) >> 32); 00330 00331 /* write output */ 00332 *pDst++ = (outR << 1u); 00333 *pDst++ = (outI << 1u); 00334 00335 /* update coefficient pointer */ 00336 pCoefB = pCoefB + (modifier * 2u); 00337 pCoefA = pCoefA + ((modifier * 2u) - 1u); 00338 00339 /* Decrement loop count */ 00340 fftLen--; 00341 00342 } 00343 00344 00345 }
