diff options
Diffstat (limited to 'Drivers/CMSIS/DSP/Source/TransformFunctions/arm_cfft_f32.c')
| -rw-r--r-- | Drivers/CMSIS/DSP/Source/TransformFunctions/arm_cfft_f32.c | 931 |
1 files changed, 470 insertions, 461 deletions
diff --git a/Drivers/CMSIS/DSP/Source/TransformFunctions/arm_cfft_f32.c b/Drivers/CMSIS/DSP/Source/TransformFunctions/arm_cfft_f32.c index 4abb6f591..2fff61cab 100644 --- a/Drivers/CMSIS/DSP/Source/TransformFunctions/arm_cfft_f32.c +++ b/Drivers/CMSIS/DSP/Source/TransformFunctions/arm_cfft_f32.c @@ -3,13 +3,13 @@ * Title: arm_cfft_f32.c * Description: Combined Radix Decimation in Frequency CFFT Floating point processing function * - * $Date: 27. January 2017 - * $Revision: V.1.5.1 + * $Date: 18. March 2019 + * $Revision: V1.6.0 * * Target Processor: Cortex-M cores * -------------------------------------------------------------------- */ /* - * Copyright (C) 2010-2017 ARM Limited or its affiliates. All rights reserved. + * Copyright (C) 2010-2019 ARM Limited or its affiliates. All rights reserved. * * SPDX-License-Identifier: Apache-2.0 * @@ -30,281 +30,283 @@ #include "arm_common_tables.h" extern void arm_radix8_butterfly_f32( - float32_t * pSrc, - uint16_t fftLen, - const float32_t * pCoef, - uint16_t twidCoefModifier); + float32_t * pSrc, + uint16_t fftLen, + const float32_t * pCoef, + uint16_t twidCoefModifier); extern void arm_bitreversal_32( - uint32_t * pSrc, - const uint16_t bitRevLen, - const uint16_t * pBitRevTable); + uint32_t * pSrc, + const uint16_t bitRevLen, + const uint16_t * pBitRevTable); /** -* @ingroup groupTransforms -*/ + @ingroup groupTransforms + */ /** -* @defgroup ComplexFFT Complex FFT Functions -* -* \par -* The Fast Fourier Transform (FFT) is an efficient algorithm for computing the -* Discrete Fourier Transform (DFT). The FFT can be orders of magnitude faster -* than the DFT, especially for long lengths. -* The algorithms described in this section -* operate on complex data. A separate set of functions is devoted to handling -* of real sequences. -* \par -* There are separate algorithms for handling floating-point, Q15, and Q31 data -* types. The algorithms available for each data type are described next. -* \par -* The FFT functions operate in-place. That is, the array holding the input data -* will also be used to hold the corresponding result. The input data is complex -* and contains <code>2*fftLen</code> interleaved values as shown below. -* <pre> {real[0], imag[0], real[1], imag[1],..} </pre> -* The FFT result will be contained in the same array and the frequency domain -* values will have the same interleaving. -* -* \par Floating-point -* The floating-point complex FFT uses a mixed-radix algorithm. Multiple radix-8 -* stages are performed along with a single radix-2 or radix-4 stage, as needed. -* The algorithm supports lengths of [16, 32, 64, ..., 4096] and each length uses -* a different twiddle factor table. -* \par -* The function uses the standard FFT definition and output values may grow by a -* factor of <code>fftLen</code> when computing the forward transform. The -* inverse transform includes a scale of <code>1/fftLen</code> as part of the -* calculation and this matches the textbook definition of the inverse FFT. -* \par -* Pre-initialized data structures containing twiddle factors and bit reversal -* tables are provided and defined in <code>arm_const_structs.h</code>. Include -* this header in your function and then pass one of the constant structures as -* an argument to arm_cfft_f32. For example: -* \par -* <code>arm_cfft_f32(arm_cfft_sR_f32_len64, pSrc, 1, 1)</code> -* \par -* computes a 64-point inverse complex FFT including bit reversal. -* The data structures are treated as constant data and not modified during the -* calculation. The same data structure can be reused for multiple transforms -* including mixing forward and inverse transforms. -* \par -* Earlier releases of the library provided separate radix-2 and radix-4 -* algorithms that operated on floating-point data. These functions are still -* provided but are deprecated. The older functions are slower and less general -* than the new functions. -* \par -* An example of initialization of the constants for the arm_cfft_f32 function follows: -* \code -* const static arm_cfft_instance_f32 *S; -* ... -* switch (length) { -* case 16: -* S = &arm_cfft_sR_f32_len16; -* break; -* case 32: -* S = &arm_cfft_sR_f32_len32; -* break; -* case 64: -* S = &arm_cfft_sR_f32_len64; -* break; -* case 128: -* S = &arm_cfft_sR_f32_len128; -* break; -* case 256: -* S = &arm_cfft_sR_f32_len256; -* break; -* case 512: -* S = &arm_cfft_sR_f32_len512; -* break; -* case 1024: -* S = &arm_cfft_sR_f32_len1024; -* break; -* case 2048: -* S = &arm_cfft_sR_f32_len2048; -* break; -* case 4096: -* S = &arm_cfft_sR_f32_len4096; -* break; -* } -* \endcode -* \par Q15 and Q31 -* The floating-point complex FFT uses a mixed-radix algorithm. Multiple radix-4 -* stages are performed along with a single radix-2 stage, as needed. -* The algorithm supports lengths of [16, 32, 64, ..., 4096] and each length uses -* a different twiddle factor table. -* \par -* The function uses the standard FFT definition and output values may grow by a -* factor of <code>fftLen</code> when computing the forward transform. The -* inverse transform includes a scale of <code>1/fftLen</code> as part of the -* calculation and this matches the textbook definition of the inverse FFT. -* \par -* Pre-initialized data structures containing twiddle factors and bit reversal -* tables are provided and defined in <code>arm_const_structs.h</code>. Include -* this header in your function and then pass one of the constant structures as -* an argument to arm_cfft_q31. For example: -* \par -* <code>arm_cfft_q31(arm_cfft_sR_q31_len64, pSrc, 1, 1)</code> -* \par -* computes a 64-point inverse complex FFT including bit reversal. -* The data structures are treated as constant data and not modified during the -* calculation. The same data structure can be reused for multiple transforms -* including mixing forward and inverse transforms. -* \par -* Earlier releases of the library provided separate radix-2 and radix-4 -* algorithms that operated on floating-point data. These functions are still -* provided but are deprecated. The older functions are slower and less general -* than the new functions. -* \par -* An example of initialization of the constants for the arm_cfft_q31 function follows: -* \code -* const static arm_cfft_instance_q31 *S; -* ... -* switch (length) { -* case 16: -* S = &arm_cfft_sR_q31_len16; -* break; -* case 32: -* S = &arm_cfft_sR_q31_len32; -* break; -* case 64: -* S = &arm_cfft_sR_q31_len64; -* break; -* case 128: -* S = &arm_cfft_sR_q31_len128; -* break; -* case 256: -* S = &arm_cfft_sR_q31_len256; -* break; -* case 512: -* S = &arm_cfft_sR_q31_len512; -* break; -* case 1024: -* S = &arm_cfft_sR_q31_len1024; -* break; -* case 2048: -* S = &arm_cfft_sR_q31_len2048; -* break; -* case 4096: -* S = &arm_cfft_sR_q31_len4096; -* break; -* } -* \endcode -* -*/ - -void arm_cfft_radix8by2_f32( arm_cfft_instance_f32 * S, float32_t * p1) + @defgroup ComplexFFT Complex FFT Functions + + @par + The Fast Fourier Transform (FFT) is an efficient algorithm for computing the + Discrete Fourier Transform (DFT). The FFT can be orders of magnitude faster + than the DFT, especially for long lengths. + The algorithms described in this section + operate on complex data. A separate set of functions is devoted to handling + of real sequences. + @par + There are separate algorithms for handling floating-point, Q15, and Q31 data + types. The algorithms available for each data type are described next. + @par + The FFT functions operate in-place. That is, the array holding the input data + will also be used to hold the corresponding result. The input data is complex + and contains <code>2*fftLen</code> interleaved values as shown below. + <pre>{real[0], imag[0], real[1], imag[1], ...} </pre> + The FFT result will be contained in the same array and the frequency domain + values will have the same interleaving. + + @par Floating-point + The floating-point complex FFT uses a mixed-radix algorithm. Multiple radix-8 + stages are performed along with a single radix-2 or radix-4 stage, as needed. + The algorithm supports lengths of [16, 32, 64, ..., 4096] and each length uses + a different twiddle factor table. + @par + The function uses the standard FFT definition and output values may grow by a + factor of <code>fftLen</code> when computing the forward transform. The + inverse transform includes a scale of <code>1/fftLen</code> as part of the + calculation and this matches the textbook definition of the inverse FFT. + @par + Pre-initialized data structures containing twiddle factors and bit reversal + tables are provided and defined in <code>arm_const_structs.h</code>. Include + this header in your function and then pass one of the constant structures as + an argument to arm_cfft_f32. For example: + @par + <code>arm_cfft_f32(arm_cfft_sR_f32_len64, pSrc, 1, 1)</code> + @par + computes a 64-point inverse complex FFT including bit reversal. + The data structures are treated as constant data and not modified during the + calculation. The same data structure can be reused for multiple transforms + including mixing forward and inverse transforms. + @par + Earlier releases of the library provided separate radix-2 and radix-4 + algorithms that operated on floating-point data. These functions are still + provided but are deprecated. The older functions are slower and less general + than the new functions. + @par + An example of initialization of the constants for the arm_cfft_f32 function follows: + @code + const static arm_cfft_instance_f32 *S; + ... + switch (length) { + case 16: + S = &arm_cfft_sR_f32_len16; + break; + case 32: + S = &arm_cfft_sR_f32_len32; + break; + case 64: + S = &arm_cfft_sR_f32_len64; + break; + case 128: + S = &arm_cfft_sR_f32_len128; + break; + case 256: + S = &arm_cfft_sR_f32_len256; + break; + case 512: + S = &arm_cfft_sR_f32_len512; + break; + case 1024: + S = &arm_cfft_sR_f32_len1024; + break; + case 2048: + S = &arm_cfft_sR_f32_len2048; + break; + case 4096: + S = &arm_cfft_sR_f32_len4096; + break; + } + @endcode + @par Q15 and Q31 + The floating-point complex FFT uses a mixed-radix algorithm. Multiple radix-4 + stages are performed along with a single radix-2 stage, as needed. + The algorithm supports lengths of [16, 32, 64, ..., 4096] and each length uses + a different twiddle factor table. + @par + The function uses the standard FFT definition and output values may grow by a + factor of <code>fftLen</code> when computing the forward transform. The + inverse transform includes a scale of <code>1/fftLen</code> as part of the + calculation and this matches the textbook definition of the inverse FFT. + @par + Pre-initialized data structures containing twiddle factors and bit reversal + tables are provided and defined in <code>arm_const_structs.h</code>. Include + this header in your function and then pass one of the constant structures as + an argument to arm_cfft_q31. For example: + @par + <code>arm_cfft_q31(arm_cfft_sR_q31_len64, pSrc, 1, 1)</code> + @par + computes a 64-point inverse complex FFT including bit reversal. + The data structures are treated as constant data and not modified during the + calculation. The same data structure can be reused for multiple transforms + including mixing forward and inverse transforms. + @par + Earlier releases of the library provided separate radix-2 and radix-4 + algorithms that operated on floating-point data. These functions are still + provided but are deprecated. The older functions are slower and less general + than the new functions. + @par + An example of initialization of the constants for the arm_cfft_q31 function follows: + @code + const static arm_cfft_instance_q31 *S; + ... + switch (length) { + case 16: + S = &arm_cfft_sR_q31_len16; + break; + case 32: + S = &arm_cfft_sR_q31_len32; + break; + case 64: + S = &arm_cfft_sR_q31_len64; + break; + case 128: + S = &arm_cfft_sR_q31_len128; + break; + case 256: + S = &arm_cfft_sR_q31_len256; + break; + case 512: + S = &arm_cfft_sR_q31_len512; + break; + case 1024: + S = &arm_cfft_sR_q31_len1024; + break; + case 2048: + S = &arm_cfft_sR_q31_len2048; + break; + case 4096: + S = &arm_cfft_sR_q31_len4096; + break; + } + @endcode + + */ + +void arm_cfft_radix8by2_f32 (arm_cfft_instance_f32 * S, float32_t * p1) { - uint32_t L = S->fftLen; - float32_t * pCol1, * pCol2, * pMid1, * pMid2; - float32_t * p2 = p1 + L; - const float32_t * tw = (float32_t *) S->pTwiddle; - float32_t t1[4], t2[4], t3[4], t4[4], twR, twI; - float32_t m0, m1, m2, m3; - uint32_t l; + uint32_t L = S->fftLen; + float32_t * pCol1, * pCol2, * pMid1, * pMid2; + float32_t * p2 = p1 + L; + const float32_t * tw = (float32_t *) S->pTwiddle; + float32_t t1[4], t2[4], t3[4], t4[4], twR, twI; + float32_t m0, m1, m2, m3; + uint32_t l; + + pCol1 = p1; + pCol2 = p2; + + /* Define new length */ + L >>= 1; + + /* Initialize mid pointers */ + pMid1 = p1 + L; + pMid2 = p2 + L; + + /* do two dot Fourier transform */ + for (l = L >> 2; l > 0; l-- ) + { + t1[0] = p1[0]; + t1[1] = p1[1]; + t1[2] = p1[2]; + t1[3] = p1[3]; + + t2[0] = p2[0]; + t2[1] = p2[1]; + t2[2] = p2[2]; + t2[3] = p2[3]; + + t3[0] = pMid1[0]; + t3[1] = pMid1[1]; + t3[2] = pMid1[2]; + t3[3] = pMid1[3]; + + t4[0] = pMid2[0]; + t4[1] = pMid2[1]; + t4[2] = pMid2[2]; + t4[3] = pMid2[3]; + + *p1++ = t1[0] + t2[0]; + *p1++ = t1[1] + t2[1]; + *p1++ = t1[2] + t2[2]; + *p1++ = t1[3] + t2[3]; /* col 1 */ + + t2[0] = t1[0] - t2[0]; + t2[1] = t1[1] - t2[1]; + t2[2] = t1[2] - t2[2]; + t2[3] = t1[3] - t2[3]; /* for col 2 */ + + *pMid1++ = t3[0] + t4[0]; + *pMid1++ = t3[1] + t4[1]; + *pMid1++ = t3[2] + t4[2]; + *pMid1++ = t3[3] + t4[3]; /* col 1 */ + + t4[0] = t4[0] - t3[0]; + t4[1] = t4[1] - t3[1]; + t4[2] = t4[2] - t3[2]; + t4[3] = t4[3] - t3[3]; /* for col 2 */ + + twR = *tw++; + twI = *tw++; + + /* multiply by twiddle factors */ + m0 = t2[0] * twR; + m1 = t2[1] * twI; + m2 = t2[1] * twR; + m3 = t2[0] * twI; - pCol1 = p1; - pCol2 = p2; + /* R = R * Tr - I * Ti */ + *p2++ = m0 + m1; + /* I = I * Tr + R * Ti */ + *p2++ = m2 - m3; - // Define new length - L >>= 1; - // Initialize mid pointers - pMid1 = p1 + L; - pMid2 = p2 + L; + /* use vertical symmetry */ + /* 0.9988 - 0.0491i <==> -0.0491 - 0.9988i */ + m0 = t4[0] * twI; + m1 = t4[1] * twR; + m2 = t4[1] * twI; + m3 = t4[0] * twR; - // do two dot Fourier transform - for ( l = L >> 2; l > 0; l-- ) - { - t1[0] = p1[0]; - t1[1] = p1[1]; - t1[2] = p1[2]; - t1[3] = p1[3]; - - t2[0] = p2[0]; - t2[1] = p2[1]; - t2[2] = p2[2]; - t2[3] = p2[3]; - - t3[0] = pMid1[0]; - t3[1] = pMid1[1]; - t3[2] = pMid1[2]; - t3[3] = pMid1[3]; - - t4[0] = pMid2[0]; - t4[1] = pMid2[1]; - t4[2] = pMid2[2]; - t4[3] = pMid2[3]; - - *p1++ = t1[0] + t2[0]; - *p1++ = t1[1] + t2[1]; - *p1++ = t1[2] + t2[2]; - *p1++ = t1[3] + t2[3]; // col 1 - - t2[0] = t1[0] - t2[0]; - t2[1] = t1[1] - t2[1]; - t2[2] = t1[2] - t2[2]; - t2[3] = t1[3] - t2[3]; // for col 2 - - *pMid1++ = t3[0] + t4[0]; - *pMid1++ = t3[1] + t4[1]; - *pMid1++ = t3[2] + t4[2]; - *pMid1++ = t3[3] + t4[3]; // col 1 - - t4[0] = t4[0] - t3[0]; - t4[1] = t4[1] - t3[1]; - t4[2] = t4[2] - t3[2]; - t4[3] = t4[3] - t3[3]; // for col 2 - - twR = *tw++; - twI = *tw++; - - // multiply by twiddle factors - m0 = t2[0] * twR; - m1 = t2[1] * twI; - m2 = t2[1] * twR; - m3 = t2[0] * twI; - - // R = R * Tr - I * Ti - *p2++ = m0 + m1; - // I = I * Tr + R * Ti - *p2++ = m2 - m3; - - // use vertical symmetry - // 0.9988 - 0.0491i <==> -0.0491 - 0.9988i - m0 = t4[0] * twI; - m1 = t4[1] * twR; - m2 = t4[1] * twI; - m3 = t4[0] * twR; - - *pMid2++ = m0 - m1; - *pMid2++ = m2 + m3; - - twR = *tw++; - twI = *tw++; - - m0 = t2[2] * twR; - m1 = t2[3] * twI; - m2 = t2[3] * twR; - m3 = t2[2] * twI; - - *p2++ = m0 + m1; - *p2++ = m2 - m3; - - m0 = t4[2] * twI; - m1 = t4[3] * twR; - m2 = t4[3] * twI; - m3 = t4[2] * twR; - - *pMid2++ = m0 - m1; - *pMid2++ = m2 + m3; - } + *pMid2++ = m0 - m1; + *pMid2++ = m2 + m3; + + twR = *tw++; + twI = *tw++; - // first col - arm_radix8_butterfly_f32( pCol1, L, (float32_t *) S->pTwiddle, 2U); - // second col - arm_radix8_butterfly_f32( pCol2, L, (float32_t *) S->pTwiddle, 2U); + m0 = t2[2] * twR; + m1 = t2[3] * twI; + m2 = t2[3] * twR; + m3 = t2[2] * twI; + + *p2++ = m0 + m1; + *p2++ = m2 - m3; + + m0 = t4[2] * twI; + m1 = t4[3] * twR; + m2 = t4[3] * twI; + m3 = t4[2] * twR; + + *pMid2++ = m0 - m1; + *pMid2++ = m2 + m3; + } + + /* first col */ + arm_radix8_butterfly_f32 (pCol1, L, (float32_t *) S->pTwiddle, 2U); + + /* second col */ + arm_radix8_butterfly_f32 (pCol2, L, (float32_t *) S->pTwiddle, 2U); } -void arm_cfft_radix8by4_f32( arm_cfft_instance_f32 * S, float32_t * p1) +void arm_cfft_radix8by4_f32 (arm_cfft_instance_f32 * S, float32_t * p1) { uint32_t L = S->fftLen >> 1; float32_t * pCol1, *pCol2, *pCol3, *pCol4, *pEnd1, *pEnd2, *pEnd3, *pEnd4; @@ -317,11 +319,11 @@ void arm_cfft_radix8by4_f32( arm_cfft_instance_f32 * S, float32_t * p1) float32_t m0, m1, m2, m3; uint32_t l, twMod2, twMod3, twMod4; - pCol1 = p1; // points to real values by default + pCol1 = p1; /* points to real values by default */ pCol2 = p2; pCol3 = p3; pCol4 = p4; - pEnd1 = p2 - 1; // points to imaginary values by default + pEnd1 = p2 - 1; /* points to imaginary values by default */ pEnd2 = p3 - 1; pEnd3 = p4 - 1; pEnd4 = pEnd3 + L; @@ -330,32 +332,32 @@ void arm_cfft_radix8by4_f32( arm_cfft_instance_f32 * S, float32_t * p1) L >>= 1; - // do four dot Fourier transform + /* do four dot Fourier transform */ twMod2 = 2; twMod3 = 4; twMod4 = 6; - // TOP + /* TOP */ p1ap3_0 = p1[0] + p3[0]; p1sp3_0 = p1[0] - p3[0]; p1ap3_1 = p1[1] + p3[1]; p1sp3_1 = p1[1] - p3[1]; - // col 2 + /* col 2 */ t2[0] = p1sp3_0 + p2[1] - p4[1]; t2[1] = p1sp3_1 - p2[0] + p4[0]; - // col 3 + /* col 3 */ t3[0] = p1ap3_0 - p2[0] - p4[0]; t3[1] = p1ap3_1 - p2[1] - p4[1]; - // col 4 + /* col 4 */ t4[0] = p1sp3_0 - p2[1] + p4[1]; t4[1] = p1sp3_1 + p2[0] - p4[0]; - // col 1 + /* col 1 */ *p1++ = p1ap3_0 + p2[0] + p4[0]; *p1++ = p1ap3_1 + p2[1] + p4[1]; - // Twiddle factors are ones + /* Twiddle factors are ones */ *p2++ = t2[0]; *p2++ = t2[1]; *p3++ = t3[0]; @@ -369,138 +371,138 @@ void arm_cfft_radix8by4_f32( arm_cfft_instance_f32 * S, float32_t * p1) for (l = (L - 2) >> 1; l > 0; l-- ) { - // TOP - p1ap3_0 = p1[0] + p3[0]; - p1sp3_0 = p1[0] - p3[0]; - p1ap3_1 = p1[1] + p3[1]; - p1sp3_1 = p1[1] - p3[1]; - // col 2 - t2[0] = p1sp3_0 + p2[1] - p4[1]; - t2[1] = p1sp3_1 - p2[0] + p4[0]; - // col 3 - t3[0] = p1ap3_0 - p2[0] - p4[0]; - t3[1] = p1ap3_1 - p2[1] - p4[1]; - // col 4 - t4[0] = p1sp3_0 - p2[1] + p4[1]; - t4[1] = p1sp3_1 + p2[0] - p4[0]; - // col 1 - top - *p1++ = p1ap3_0 + p2[0] + p4[0]; - *p1++ = p1ap3_1 + p2[1] + p4[1]; - - // BOTTOM - p1ap3_1 = pEnd1[-1] + pEnd3[-1]; - p1sp3_1 = pEnd1[-1] - pEnd3[-1]; - p1ap3_0 = pEnd1[0] + pEnd3[0]; - p1sp3_0 = pEnd1[0] - pEnd3[0]; - // col 2 - t2[2] = pEnd2[0] - pEnd4[0] + p1sp3_1; - t2[3] = pEnd1[0] - pEnd3[0] - pEnd2[-1] + pEnd4[-1]; - // col 3 - t3[2] = p1ap3_1 - pEnd2[-1] - pEnd4[-1]; - t3[3] = p1ap3_0 - pEnd2[0] - pEnd4[0]; - // col 4 - t4[2] = pEnd2[0] - pEnd4[0] - p1sp3_1; - t4[3] = pEnd4[-1] - pEnd2[-1] - p1sp3_0; - // col 1 - Bottom - *pEnd1-- = p1ap3_0 + pEnd2[0] + pEnd4[0]; - *pEnd1-- = p1ap3_1 + pEnd2[-1] + pEnd4[-1]; - - // COL 2 - // read twiddle factors - twR = *tw2++; - twI = *tw2++; - // multiply by twiddle factors - // let Z1 = a + i(b), Z2 = c + i(d) - // => Z1 * Z2 = (a*c - b*d) + i(b*c + a*d) - - // Top - m0 = t2[0] * twR; - m1 = t2[1] * twI; - m2 = t2[1] * twR; - m3 = t2[0] * twI; - - *p2++ = m0 + m1; - *p2++ = m2 - m3; - // use vertical symmetry col 2 - // 0.9997 - 0.0245i <==> 0.0245 - 0.9997i - // Bottom - m0 = t2[3] * twI; - m1 = t2[2] * twR; - m2 = t2[2] * twI; - m3 = t2[3] * twR; - - *pEnd2-- = m0 - m1; - *pEnd2-- = m2 + m3; - - // COL 3 - twR = tw3[0]; - twI = tw3[1]; - tw3 += twMod3; - // Top - m0 = t3[0] * twR; - m1 = t3[1] * twI; - m2 = t3[1] * twR; - m3 = t3[0] * twI; - - *p3++ = m0 + m1; - *p3++ = m2 - m3; - // use vertical symmetry col 3 - // 0.9988 - 0.0491i <==> -0.9988 - 0.0491i - // Bottom - m0 = -t3[3] * twR; - m1 = t3[2] * twI; - m2 = t3[2] * twR; - m3 = t3[3] * twI; - - *pEnd3-- = m0 - m1; - *pEnd3-- = m3 - m2; - - // COL 4 - twR = tw4[0]; - twI = tw4[1]; - tw4 += twMod4; - // Top - m0 = t4[0] * twR; - m1 = t4[1] * twI; - m2 = t4[1] * twR; - m3 = t4[0] * twI; - - *p4++ = m0 + m1; - *p4++ = m2 - m3; - // use vertical symmetry col 4 - // 0.9973 - 0.0736i <==> -0.0736 + 0.9973i - // Bottom - m0 = t4[3] * twI; - m1 = t4[2] * twR; - m2 = t4[2] * twI; - m3 = t4[3] * twR; - - *pEnd4-- = m0 - m1; - *pEnd4-- = m2 + m3; + /* TOP */ + p1ap3_0 = p1[0] + p3[0]; + p1sp3_0 = p1[0] - p3[0]; + p1ap3_1 = p1[1] + p3[1]; + p1sp3_1 = p1[1] - p3[1]; + /* col 2 */ + t2[0] = p1sp3_0 + p2[1] - p4[1]; + t2[1] = p1sp3_1 - p2[0] + p4[0]; + /* col 3 */ + t3[0] = p1ap3_0 - p2[0] - p4[0]; + t3[1] = p1ap3_1 - p2[1] - p4[1]; + /* col 4 */ + t4[0] = p1sp3_0 - p2[1] + p4[1]; + t4[1] = p1sp3_1 + p2[0] - p4[0]; + /* col 1 - top */ + *p1++ = p1ap3_0 + p2[0] + p4[0]; + *p1++ = p1ap3_1 + p2[1] + p4[1]; + + /* BOTTOM */ + p1ap3_1 = pEnd1[-1] + pEnd3[-1]; + p1sp3_1 = pEnd1[-1] - pEnd3[-1]; + p1ap3_0 = pEnd1[ 0] + pEnd3[0]; + p1sp3_0 = pEnd1[ 0] - pEnd3[0]; + /* col 2 */ + t2[2] = pEnd2[0] - pEnd4[0] + p1sp3_1; + t2[3] = pEnd1[0] - pEnd3[0] - pEnd2[-1] + pEnd4[-1]; + /* col 3 */ + t3[2] = p1ap3_1 - pEnd2[-1] - pEnd4[-1]; + t3[3] = p1ap3_0 - pEnd2[ 0] - pEnd4[ 0]; + /* col 4 */ + t4[2] = pEnd2[ 0] - pEnd4[ 0] - p1sp3_1; + t4[3] = pEnd4[-1] - pEnd2[-1] - p1sp3_0; + /* col 1 - Bottom */ + *pEnd1-- = p1ap3_0 + pEnd2[ 0] + pEnd4[ 0]; + *pEnd1-- = p1ap3_1 + pEnd2[-1] + pEnd4[-1]; + + /* COL 2 */ + /* read twiddle factors */ + twR = *tw2++; + twI = *tw2++; + /* multiply by twiddle factors */ + /* let Z1 = a + i(b), Z2 = c + i(d) */ + /* => Z1 * Z2 = (a*c - b*d) + i(b*c + a*d) */ + + /* Top */ + m0 = t2[0] * twR; + m1 = t2[1] * twI; + m2 = t2[1] * twR; + m3 = t2[0] * twI; + + *p2++ = m0 + m1; + *p2++ = m2 - m3; + /* use vertical symmetry col 2 */ + /* 0.9997 - 0.0245i <==> 0.0245 - 0.9997i */ + /* Bottom */ + m0 = t2[3] * twI; + m1 = t2[2] * twR; + m2 = t2[2] * twI; + m3 = t2[3] * twR; + + *pEnd2-- = m0 - m1; + *pEnd2-- = m2 + m3; + + /* COL 3 */ + twR = tw3[0]; + twI = tw3[1]; + tw3 += twMod3; + /* Top */ + m0 = t3[0] * twR; + m1 = t3[1] * twI; + m2 = t3[1] * twR; + m3 = t3[0] * twI; + + *p3++ = m0 + m1; + *p3++ = m2 - m3; + /* use vertical symmetry col 3 */ + /* 0.9988 - 0.0491i <==> -0.9988 - 0.0491i */ + /* Bottom */ + m0 = -t3[3] * twR; + m1 = t3[2] * twI; + m2 = t3[2] * twR; + m3 = t3[3] * twI; + + *pEnd3-- = m0 - m1; + *pEnd3-- = m3 - m2; + + /* COL 4 */ + twR = tw4[0]; + twI = tw4[1]; + tw4 += twMod4; + /* Top */ + m0 = t4[0] * twR; + m1 = t4[1] * twI; + m2 = t4[1] * twR; + m3 = t4[0] * twI; + + *p4++ = m0 + m1; + *p4++ = m2 - m3; + /* use vertical symmetry col 4 */ + /* 0.9973 - 0.0736i <==> -0.0736 + 0.9973i */ + /* Bottom */ + m0 = t4[3] * twI; + m1 = t4[2] * twR; + m2 = t4[2] * twI; + m3 = t4[3] * twR; + + *pEnd4-- = m0 - m1; + *pEnd4-- = m2 + m3; } - //MIDDLE - // Twiddle factors are - // 1.0000 0.7071-0.7071i -1.0000i -0.7071-0.7071i + /* MIDDLE */ + /* Twiddle factors are */ + /* 1.0000 0.7071-0.7071i -1.0000i -0.7071-0.7071i */ p1ap3_0 = p1[0] + p3[0]; p1sp3_0 = p1[0] - p3[0]; p1ap3_1 = p1[1] + p3[1]; p1sp3_1 = p1[1] - p3[1]; - // col 2 + /* col 2 */ t2[0] = p1sp3_0 + p2[1] - p4[1]; t2[1] = p1sp3_1 - p2[0] + p4[0]; - // col 3 + /* col 3 */ t3[0] = p1ap3_0 - p2[0] - p4[0]; t3[1] = p1ap3_1 - p2[1] - p4[1]; - // col 4 + /* col 4 */ t4[0] = p1sp3_0 - p2[1] + p4[1]; t4[1] = p1sp3_1 + p2[0] - p4[0]; - // col 1 - Top + /* col 1 - Top */ *p1++ = p1ap3_0 + p2[0] + p4[0]; *p1++ = p1ap3_1 + p2[1] + p4[1]; - // COL 2 + /* COL 2 */ twR = tw2[0]; twI = tw2[1]; @@ -511,7 +513,7 @@ void arm_cfft_radix8by4_f32( arm_cfft_instance_f32 * S, float32_t * p1) *p2++ = m0 + m1; *p2++ = m2 - m3; - // COL 3 + /* COL 3 */ twR = tw3[0]; twI = tw3[1]; @@ -522,7 +524,7 @@ void arm_cfft_radix8by4_f32( arm_cfft_instance_f32 * S, float32_t * p1) *p3++ = m0 + m1; *p3++ = m2 - m3; - // COL 4 + /* COL 4 */ twR = tw4[0]; twI = tw4[1]; @@ -534,87 +536,94 @@ void arm_cfft_radix8by4_f32( arm_cfft_instance_f32 * S, float32_t * p1) *p4++ = m0 + m1; *p4++ = m2 - m3; - // first col - arm_radix8_butterfly_f32( pCol1, L, (float32_t *) S->pTwiddle, 4U); - // second col - arm_radix8_butterfly_f32( pCol2, L, (float32_t *) S->pTwiddle, 4U); - // third col - arm_radix8_butterfly_f32( pCol3, L, (float32_t *) S->pTwiddle, 4U); - // fourth col - arm_radix8_butterfly_f32( pCol4, L, (float32_t *) S->pTwiddle, 4U); + /* first col */ + arm_radix8_butterfly_f32 (pCol1, L, (float32_t *) S->pTwiddle, 4U); + + /* second col */ + arm_radix8_butterfly_f32 (pCol2, L, (float32_t *) S->pTwiddle, 4U); + + /* third col */ + arm_radix8_butterfly_f32 (pCol3, L, (float32_t *) S->pTwiddle, 4U); + + /* fourth col */ + arm_radix8_butterfly_f32 (pCol4, L, (float32_t *) S->pTwiddle, 4U); } /** -* @addtogroup ComplexFFT -* @{ -*/ + @addtogroup ComplexFFT + @{ + */ /** -* @details -* @brief Processing function for the floating-point complex FFT. -* @param[in] *S points to an instance of the floating-point CFFT structure. -* @param[in, out] *p1 points to the complex data buffer of size <code>2*fftLen</code>. Processing occurs in-place. -* @param[in] ifftFlag flag that selects forward (ifftFlag=0) or inverse (ifftFlag=1) transform. -* @param[in] bitReverseFlag flag that enables (bitReverseFlag=1) or disables (bitReverseFlag=0) bit reversal of output. -* @return none. -*/ + @brief Processing function for the floating-point complex FFT. + @param[in] S points to an instance of the floating-point CFFT structure + @param[in,out] p1 points to the complex data buffer of size <code>2*fftLen</code>. Processing occurs in-place + @param[in] ifftFlag flag that selects transform direction + - value = 0: forward transform + - value = 1: inverse transform + @param[in] bitReverseFlag flag that enables / disables bit reversal of output + - value = 0: disables bit reversal of output + - value = 1: enables bit reversal of output + @return none + */ void arm_cfft_f32( - const arm_cfft_instance_f32 * S, - float32_t * p1, - uint8_t ifftFlag, - uint8_t bitReverseFlag) + const arm_cfft_instance_f32 * S, + float32_t * p1, + uint8_t ifftFlag, + uint8_t bitReverseFlag) { - uint32_t L = S->fftLen, l; - float32_t invL, * pSrc; - - if (ifftFlag == 1U) - { - /* Conjugate input data */ - pSrc = p1 + 1; - for(l=0; l<L; l++) - { - *pSrc = -*pSrc; - pSrc += 2; - } - } - - switch (L) + uint32_t L = S->fftLen, l; + float32_t invL, * pSrc; + + if (ifftFlag == 1U) + { + /* Conjugate input data */ + pSrc = p1 + 1; + for (l = 0; l < L; l++) { - case 16: - case 128: - case 1024: - arm_cfft_radix8by2_f32 ( (arm_cfft_instance_f32 *) S, p1); - break; - case 32: - case 256: - case 2048: - arm_cfft_radix8by4_f32 ( (arm_cfft_instance_f32 *) S, p1); - break; - case 64: - case 512: - case 4096: - arm_radix8_butterfly_f32( p1, L, (float32_t *) S->pTwiddle, 1); - break; + *pSrc = -*pSrc; + pSrc += 2; } - - if ( bitReverseFlag ) - arm_bitreversal_32((uint32_t*)p1,S->bitRevLength,S->pBitRevTable); - - if (ifftFlag == 1U) + } + + switch (L) + { + case 16: + case 128: + case 1024: + arm_cfft_radix8by2_f32 ( (arm_cfft_instance_f32 *) S, p1); + break; + case 32: + case 256: + case 2048: + arm_cfft_radix8by4_f32 ( (arm_cfft_instance_f32 *) S, p1); + break; + case 64: + case 512: + case 4096: + arm_radix8_butterfly_f32 ( p1, L, (float32_t *) S->pTwiddle, 1); + break; + } + + if ( bitReverseFlag ) + arm_bitreversal_32 ((uint32_t*) p1, S->bitRevLength, S->pBitRevTable); + + if (ifftFlag == 1U) + { + invL = 1.0f / (float32_t)L; + + /* Conjugate and scale output data */ + pSrc = p1; + for (l= 0; l < L; l++) { - invL = 1.0f/(float32_t)L; - /* Conjugate and scale output data */ - pSrc = p1; - for(l=0; l<L; l++) - { - *pSrc++ *= invL ; - *pSrc = -(*pSrc) * invL; - pSrc++; - } + *pSrc++ *= invL ; + *pSrc = -(*pSrc) * invL; + pSrc++; } + } } /** -* @} end of ComplexFFT group -*/ + @} end of ComplexFFT group + */ |