arm_rfft_q15.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_q15.c 00009 * 00010 * Description: RFFT & RIFFT Q15 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 00025 #include "arm_math.h" 00026 00027 /*-------------------------------------------------------------------- 00028 * Internal functions prototypes 00029 --------------------------------------------------------------------*/ 00030 00031 void arm_split_rfft_q15( 00032 q15_t * pSrc, 00033 uint32_t fftLen, 00034 q15_t * pATable, 00035 q15_t * pBTable, 00036 q15_t * pDst, 00037 uint32_t modifier); 00038 00039 void arm_split_rifft_q15( 00040 q15_t * pSrc, 00041 uint32_t fftLen, 00042 q15_t * pATable, 00043 q15_t * pBTable, 00044 q15_t * pDst, 00045 uint32_t modifier); 00046 00070 void arm_rfft_q15( 00071 const arm_rfft_instance_q15 * S, 00072 q15_t * pSrc, 00073 q15_t * pDst) 00074 { 00075 const arm_cfft_radix4_instance_q15 *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_q15(pSrc, S->fftLenBy2, S->pTwiddleAReal, 00082 S->pTwiddleBReal, pDst, S->twidCoefRModifier); 00083 00084 /* Complex readix-4 IFFT process */ 00085 arm_radix4_butterfly_inverse_q15(pDst, S_CFFT->fftLen, 00086 S_CFFT->pTwiddle, 00087 S_CFFT->twidCoefModifier); 00088 00089 /* Bit reversal process */ 00090 if(S->bitReverseFlagR == 1u) 00091 { 00092 arm_bitreversal_q15(pDst, S_CFFT->fftLen, 00093 S_CFFT->bitRevFactor, S_CFFT->pBitRevTable); 00094 } 00095 } 00096 else 00097 { 00098 /* Calculation of RFFT of input */ 00099 00100 /* Complex readix-4 FFT process */ 00101 arm_radix4_butterfly_q15(pSrc, S_CFFT->fftLen, 00102 S_CFFT->pTwiddle, S_CFFT->twidCoefModifier); 00103 00104 /* Bit reversal process */ 00105 if(S->bitReverseFlagR == 1u) 00106 { 00107 arm_bitreversal_q15(pSrc, S_CFFT->fftLen, 00108 S_CFFT->bitRevFactor, S_CFFT->pBitRevTable); 00109 } 00110 00111 arm_split_rfft_q15(pSrc, S->fftLenBy2, S->pTwiddleAReal, 00112 S->pTwiddleBReal, pDst, S->twidCoefRModifier); 00113 } 00114 00115 } 00116 00133 void arm_split_rfft_q15( 00134 q15_t * pSrc, 00135 uint32_t fftLen, 00136 q15_t * pATable, 00137 q15_t * pBTable, 00138 q15_t * pDst, 00139 uint32_t modifier) 00140 { 00141 uint32_t i; /* Loop Counter */ 00142 q31_t outR, outI; /* Temporary variables for output */ 00143 q15_t *pCoefA, *pCoefB; /* Temporary pointers for twiddle factors */ 00144 q15_t *pSrc1, *pSrc2; 00145 q31_t in1, in2, coeffA, coeffB; 00146 00147 pCoefA = &pATable[modifier * 2u]; 00148 pCoefB = &pBTable[modifier * 2u]; 00149 00150 pSrc1 = &pSrc[2]; 00151 pSrc2 = &pSrc[(2u * fftLen) - 2u]; 00152 00153 i = 1u; 00154 00155 while(i < fftLen) 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 in1 = *__SIMD32(pSrc1)++; 00167 in2 = *__SIMD32(pSrc2)--; 00168 coeffA = *__SIMD32(pCoefA); 00169 coeffB = *__SIMD32(pCoefB); 00170 00171 #ifndef ARM_MATH_BIG_ENDIAN 00172 00173 /* pSrc[2 * i] * pATable[2 * i] - pSrc[2 * i + 1] * pATable[2 * i + 1] */ 00174 outR = __SMUSD(in1, coeffA); 00175 00176 #else 00177 00178 /* -(pSrc[2 * i + 1] * pATable[2 * i + 1] - pSrc[2 * i] * pATable[2 * i]) */ 00179 outR = -(__SMUSD(in1, coeffA)); 00180 00181 #endif /* #ifndef ARM_MATH_BIG_ENDIAN */ 00182 00183 /* pSrc[2 * n - 2 * i] * pBTable[2 * i] + 00184 pSrc[2 * n - 2 * i + 1] * pBTable[2 * i + 1]) */ 00185 outR = __SMLAD(in2, coeffB, outR) >> 15u; 00186 00187 /* pIn[2 * n - 2 * i] * pBTable[2 * i + 1] - 00188 pIn[2 * n - 2 * i + 1] * pBTable[2 * i] */ 00189 00190 #ifndef ARM_MATH_BIG_ENDIAN 00191 00192 outI = __SMUSDX(in2, coeffB); 00193 00194 #else 00195 00196 outI = __SMUSDX(coeffB, in2); 00197 00198 #endif /* #ifndef ARM_MATH_BIG_ENDIAN */ 00199 00200 /* (pIn[2 * i + 1] * pATable[2 * i] + pIn[2 * i] * pATable[2 * i + 1] */ 00201 outI = __SMLADX(in1, coeffA, outI); 00202 00203 /* write output */ 00204 pDst[2u * i] = (q15_t) outR; 00205 pDst[(2u * i) + 1u] = outI >> 15u; 00206 00207 /* write complex conjugate output */ 00208 pDst[(4u * fftLen) - (2u * i)] = (q15_t) outR; 00209 pDst[((4u * fftLen) - (2u * i)) + 1u] = -(outI >> 15u); 00210 00211 /* update coefficient pointer */ 00212 pCoefB = pCoefB + (2u * modifier); 00213 pCoefA = pCoefA + (2u * modifier); 00214 00215 i++; 00216 00217 } 00218 00219 pDst[2u * fftLen] = pSrc[0] - pSrc[1]; 00220 pDst[(2u * fftLen) + 1u] = 0; 00221 00222 pDst[0] = pSrc[0] + pSrc[1]; 00223 pDst[1] = 0; 00224 00225 } 00226 00227 00240 void arm_split_rifft_q15( 00241 q15_t * pSrc, 00242 uint32_t fftLen, 00243 q15_t * pATable, 00244 q15_t * pBTable, 00245 q15_t * pDst, 00246 uint32_t modifier) 00247 { 00248 uint32_t i; /* Loop Counter */ 00249 q31_t outR, outI; /* Temporary variables for output */ 00250 q15_t *pCoefA, *pCoefB; /* Temporary pointers for twiddle factors */ 00251 q15_t *pSrc1, *pSrc2; 00252 q15_t *pDst1 = &pDst[0]; 00253 q31_t in1, in2, coeffA, coeffB; 00254 00255 pCoefA = &pATable[0]; 00256 pCoefB = &pBTable[0]; 00257 00258 pSrc1 = &pSrc[0]; 00259 pSrc2 = &pSrc[2u * fftLen]; 00260 00261 i = fftLen; 00262 00263 while(i > 0u) 00264 { 00265 00266 /* 00267 outR = (pIn[2 * i] * pATable[2 * i] + pIn[2 * i + 1] * pATable[2 * i + 1] + 00268 pIn[2 * n - 2 * i] * pBTable[2 * i] - 00269 pIn[2 * n - 2 * i + 1] * pBTable[2 * i + 1]); 00270 00271 outI = (pIn[2 * i + 1] * pATable[2 * i] - pIn[2 * i] * pATable[2 * i + 1] - 00272 pIn[2 * n - 2 * i] * pBTable[2 * i + 1] - 00273 pIn[2 * n - 2 * i + 1] * pBTable[2 * i]); 00274 00275 */ 00276 00277 in2 = *__SIMD32(pSrc2)--; 00278 in1 = *__SIMD32(pSrc1)++; 00279 coeffB = *__SIMD32(pCoefB); 00280 coeffA = *__SIMD32(pCoefA); 00281 00282 00283 #ifndef ARM_MATH_BIG_ENDIAN 00284 00285 /* pIn[2 * n - 2 * i] * pBTable[2 * i] - 00286 pIn[2 * n - 2 * i + 1] * pBTable[2 * i + 1]) */ 00287 outR = __SMUSD(in2, coeffB); 00288 00289 #else 00290 00291 /* -(-pIn[2 * n - 2 * i] * pBTable[2 * i] + 00292 pIn[2 * n - 2 * i + 1] * pBTable[2 * i + 1])) */ 00293 outR = -(__SMUSD(in2, coeffB)); 00294 00295 #endif /* #ifndef ARM_MATH_BIG_ENDIAN */ 00296 00297 /* pIn[2 * i] * pATable[2 * i] + pIn[2 * i + 1] * pATable[2 * i + 1] + 00298 pIn[2 * n - 2 * i] * pBTable[2 * i] */ 00299 outR = __SMLAD(in1, coeffA, outR) >> 15u; 00300 00301 /* 00302 -pIn[2 * n - 2 * i] * pBTable[2 * i + 1] + 00303 pIn[2 * n - 2 * i + 1] * pBTable[2 * i] */ 00304 outI = __SMUADX(in2, coeffB); 00305 00306 /* pIn[2 * i + 1] * pATable[2 * i] - pIn[2 * i] * pATable[2 * i + 1] */ 00307 00308 #ifndef ARM_MATH_BIG_ENDIAN 00309 00310 outI = __SMLSDX(coeffA, in1, -outI); 00311 00312 #else 00313 00314 outI = __SMLSDX(in1, coeffA, -outI); 00315 00316 #endif /* #ifndef ARM_MATH_BIG_ENDIAN */ 00317 /* write output */ 00318 00319 #ifndef ARM_MATH_BIG_ENDIAN 00320 00321 *__SIMD32(pDst1)++ = __PKHBT(outR, (outI >> 15u), 16); 00322 00323 #else 00324 00325 *__SIMD32(pDst1)++ = __PKHBT((outI >> 15u), outR, 16); 00326 00327 #endif /* #ifndef ARM_MATH_BIG_ENDIAN */ 00328 00329 /* update coefficient pointer */ 00330 pCoefB = pCoefB + (2u * modifier); 00331 pCoefA = pCoefA + (2u * modifier); 00332 00333 i--; 00334 00335 } 00336 00337 }
