| /* ---------------------------------------------------------------------- |
| * Project: CMSIS DSP Library |
| * Title: arm_cfft_radix2_f32.c |
| * Description: Radix-2 Decimation in Frequency CFFT & CIFFT Floating point processing function |
| * |
| * $Date: 18. March 2019 |
| * $Revision: V1.6.0 |
| * |
| * Target Processor: Cortex-M cores |
| * -------------------------------------------------------------------- */ |
| /* |
| * Copyright (C) 2010-2019 ARM Limited or its affiliates. All rights reserved. |
| * |
| * SPDX-License-Identifier: Apache-2.0 |
| * |
| * Licensed under the Apache License, Version 2.0 (the License); you may |
| * not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an AS IS BASIS, WITHOUT |
| * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| #include "arm_math.h" |
| |
| void arm_radix2_butterfly_f32( |
| float32_t * pSrc, |
| uint32_t fftLen, |
| const float32_t * pCoef, |
| uint16_t twidCoefModifier); |
| |
| void arm_radix2_butterfly_inverse_f32( |
| float32_t * pSrc, |
| uint32_t fftLen, |
| const float32_t * pCoef, |
| uint16_t twidCoefModifier, |
| float32_t onebyfftLen); |
| |
| extern void arm_bitreversal_f32( |
| float32_t * pSrc, |
| uint16_t fftSize, |
| uint16_t bitRevFactor, |
| const uint16_t * pBitRevTab); |
| |
| /** |
| @ingroup groupTransforms |
| */ |
| |
| /** |
| @addtogroup ComplexFFT |
| @{ |
| */ |
| |
| /** |
| @brief Radix-2 CFFT/CIFFT. |
| @deprecated Do not use this function. It has been superseded by \ref arm_cfft_f32 and will be removed in the future |
| @param[in] S points to an instance of the floating-point Radix-2 CFFT/CIFFT structure |
| @param[in,out] pSrc points to the complex data buffer of size <code>2*fftLen</code>. Processing occurs in-place |
| @return none |
| */ |
| |
| void arm_cfft_radix2_f32( |
| const arm_cfft_radix2_instance_f32 * S, |
| float32_t * pSrc) |
| { |
| |
| if (S->ifftFlag == 1U) |
| { |
| /* Complex IFFT radix-2 */ |
| arm_radix2_butterfly_inverse_f32(pSrc, S->fftLen, S->pTwiddle, |
| S->twidCoefModifier, S->onebyfftLen); |
| } |
| else |
| { |
| /* Complex FFT radix-2 */ |
| arm_radix2_butterfly_f32(pSrc, S->fftLen, S->pTwiddle, |
| S->twidCoefModifier); |
| } |
| |
| if (S->bitReverseFlag == 1U) |
| { |
| /* Bit Reversal */ |
| arm_bitreversal_f32(pSrc, S->fftLen, S->bitRevFactor, S->pBitRevTable); |
| } |
| |
| } |
| |
| |
| /** |
| @} end of ComplexFFT group |
| */ |
| |
| |
| |
| /* ---------------------------------------------------------------------- |
| ** Internal helper function used by the FFTs |
| ** ------------------------------------------------------------------- */ |
| |
| /** |
| brief Core function for the floating-point CFFT butterfly process. |
| param[in,out] pSrc points to in-place buffer of floating-point data type |
| param[in] fftLen length of the FFT |
| param[in] pCoef points to twiddle coefficient buffer |
| param[in] twidCoefModifier twiddle coefficient modifier that supports different size FFTs with the same twiddle factor table |
| return none |
| */ |
| |
| void arm_radix2_butterfly_f32( |
| float32_t * pSrc, |
| uint32_t fftLen, |
| const float32_t * pCoef, |
| uint16_t twidCoefModifier) |
| { |
| |
| uint32_t i, j, k, l; |
| uint32_t n1, n2, ia; |
| float32_t xt, yt, cosVal, sinVal; |
| float32_t p0, p1, p2, p3; |
| float32_t a0, a1; |
| |
| #if defined (ARM_MATH_DSP) |
| |
| /* Initializations for the first stage */ |
| n2 = fftLen >> 1; |
| ia = 0; |
| i = 0; |
| |
| // loop for groups |
| for (k = n2; k > 0; k--) |
| { |
| cosVal = pCoef[ia * 2]; |
| sinVal = pCoef[(ia * 2) + 1]; |
| |
| /* Twiddle coefficients index modifier */ |
| ia += twidCoefModifier; |
| |
| /* index calculation for the input as, */ |
| /* pSrc[i + 0], pSrc[i + fftLen/1] */ |
| l = i + n2; |
| |
| /* Butterfly implementation */ |
| a0 = pSrc[2 * i] + pSrc[2 * l]; |
| xt = pSrc[2 * i] - pSrc[2 * l]; |
| |
| yt = pSrc[2 * i + 1] - pSrc[2 * l + 1]; |
| a1 = pSrc[2 * l + 1] + pSrc[2 * i + 1]; |
| |
| p0 = xt * cosVal; |
| p1 = yt * sinVal; |
| p2 = yt * cosVal; |
| p3 = xt * sinVal; |
| |
| pSrc[2 * i] = a0; |
| pSrc[2 * i + 1] = a1; |
| |
| pSrc[2 * l] = p0 + p1; |
| pSrc[2 * l + 1] = p2 - p3; |
| |
| i++; |
| } // groups loop end |
| |
| twidCoefModifier <<= 1U; |
| |
| // loop for stage |
| for (k = n2; k > 2; k = k >> 1) |
| { |
| n1 = n2; |
| n2 = n2 >> 1; |
| ia = 0; |
| |
| // loop for groups |
| j = 0; |
| do |
| { |
| cosVal = pCoef[ia * 2]; |
| sinVal = pCoef[(ia * 2) + 1]; |
| ia += twidCoefModifier; |
| |
| // loop for butterfly |
| i = j; |
| do |
| { |
| l = i + n2; |
| a0 = pSrc[2 * i] + pSrc[2 * l]; |
| xt = pSrc[2 * i] - pSrc[2 * l]; |
| |
| yt = pSrc[2 * i + 1] - pSrc[2 * l + 1]; |
| a1 = pSrc[2 * l + 1] + pSrc[2 * i + 1]; |
| |
| p0 = xt * cosVal; |
| p1 = yt * sinVal; |
| p2 = yt * cosVal; |
| p3 = xt * sinVal; |
| |
| pSrc[2 * i] = a0; |
| pSrc[2 * i + 1] = a1; |
| |
| pSrc[2 * l] = p0 + p1; |
| pSrc[2 * l + 1] = p2 - p3; |
| |
| i += n1; |
| } while ( i < fftLen ); // butterfly loop end |
| j++; |
| } while ( j < n2); // groups loop end |
| twidCoefModifier <<= 1U; |
| } // stages loop end |
| |
| // loop for butterfly |
| for (i = 0; i < fftLen; i += 2) |
| { |
| a0 = pSrc[2 * i] + pSrc[2 * i + 2]; |
| xt = pSrc[2 * i] - pSrc[2 * i + 2]; |
| |
| yt = pSrc[2 * i + 1] - pSrc[2 * i + 3]; |
| a1 = pSrc[2 * i + 3] + pSrc[2 * i + 1]; |
| |
| pSrc[2 * i] = a0; |
| pSrc[2 * i + 1] = a1; |
| pSrc[2 * i + 2] = xt; |
| pSrc[2 * i + 3] = yt; |
| } // groups loop end |
| |
| #else /* #if defined (ARM_MATH_DSP) */ |
| |
| n2 = fftLen; |
| |
| // loop for stage |
| for (k = fftLen; k > 1; k = k >> 1) |
| { |
| n1 = n2; |
| n2 = n2 >> 1; |
| ia = 0; |
| |
| // loop for groups |
| j = 0; |
| do |
| { |
| cosVal = pCoef[ia * 2]; |
| sinVal = pCoef[(ia * 2) + 1]; |
| ia += twidCoefModifier; |
| |
| // loop for butterfly |
| i = j; |
| do |
| { |
| l = i + n2; |
| a0 = pSrc[2 * i] + pSrc[2 * l]; |
| xt = pSrc[2 * i] - pSrc[2 * l]; |
| |
| yt = pSrc[2 * i + 1] - pSrc[2 * l + 1]; |
| a1 = pSrc[2 * l + 1] + pSrc[2 * i + 1]; |
| |
| p0 = xt * cosVal; |
| p1 = yt * sinVal; |
| p2 = yt * cosVal; |
| p3 = xt * sinVal; |
| |
| pSrc[2 * i] = a0; |
| pSrc[2 * i + 1] = a1; |
| |
| pSrc[2 * l] = p0 + p1; |
| pSrc[2 * l + 1] = p2 - p3; |
| |
| i += n1; |
| } while (i < fftLen); |
| j++; |
| } while (j < n2); |
| twidCoefModifier <<= 1U; |
| } |
| |
| #endif /* #if defined (ARM_MATH_DSP) */ |
| |
| } |
| |
| |
| void arm_radix2_butterfly_inverse_f32( |
| float32_t * pSrc, |
| uint32_t fftLen, |
| const float32_t * pCoef, |
| uint16_t twidCoefModifier, |
| float32_t onebyfftLen) |
| { |
| |
| uint32_t i, j, k, l; |
| uint32_t n1, n2, ia; |
| float32_t xt, yt, cosVal, sinVal; |
| float32_t p0, p1, p2, p3; |
| float32_t a0, a1; |
| |
| #if defined (ARM_MATH_DSP) |
| |
| n2 = fftLen >> 1; |
| ia = 0; |
| |
| // loop for groups |
| for (i = 0; i < n2; i++) |
| { |
| cosVal = pCoef[ia * 2]; |
| sinVal = pCoef[(ia * 2) + 1]; |
| ia += twidCoefModifier; |
| |
| l = i + n2; |
| a0 = pSrc[2 * i] + pSrc[2 * l]; |
| xt = pSrc[2 * i] - pSrc[2 * l]; |
| |
| yt = pSrc[2 * i + 1] - pSrc[2 * l + 1]; |
| a1 = pSrc[2 * l + 1] + pSrc[2 * i + 1]; |
| |
| p0 = xt * cosVal; |
| p1 = yt * sinVal; |
| p2 = yt * cosVal; |
| p3 = xt * sinVal; |
| |
| pSrc[2 * i] = a0; |
| pSrc[2 * i + 1] = a1; |
| |
| pSrc[2 * l] = p0 - p1; |
| pSrc[2 * l + 1] = p2 + p3; |
| } // groups loop end |
| |
| twidCoefModifier <<= 1U; |
| |
| // loop for stage |
| for (k = fftLen / 2; k > 2; k = k >> 1) |
| { |
| n1 = n2; |
| n2 = n2 >> 1; |
| ia = 0; |
| |
| // loop for groups |
| j = 0; |
| do |
| { |
| cosVal = pCoef[ia * 2]; |
| sinVal = pCoef[(ia * 2) + 1]; |
| ia += twidCoefModifier; |
| |
| // loop for butterfly |
| i = j; |
| do |
| { |
| l = i + n2; |
| a0 = pSrc[2 * i] + pSrc[2 * l]; |
| xt = pSrc[2 * i] - pSrc[2 * l]; |
| |
| yt = pSrc[2 * i + 1] - pSrc[2 * l + 1]; |
| a1 = pSrc[2 * l + 1] + pSrc[2 * i + 1]; |
| |
| p0 = xt * cosVal; |
| p1 = yt * sinVal; |
| p2 = yt * cosVal; |
| p3 = xt * sinVal; |
| |
| pSrc[2 * i] = a0; |
| pSrc[2 * i + 1] = a1; |
| |
| pSrc[2 * l] = p0 - p1; |
| pSrc[2 * l + 1] = p2 + p3; |
| |
| i += n1; |
| } while ( i < fftLen ); // butterfly loop end |
| j++; |
| } while (j < n2); // groups loop end |
| |
| twidCoefModifier <<= 1U; |
| } // stages loop end |
| |
| // loop for butterfly |
| for (i = 0; i < fftLen; i += 2) |
| { |
| a0 = pSrc[2 * i] + pSrc[2 * i + 2]; |
| xt = pSrc[2 * i] - pSrc[2 * i + 2]; |
| |
| a1 = pSrc[2 * i + 3] + pSrc[2 * i + 1]; |
| yt = pSrc[2 * i + 1] - pSrc[2 * i + 3]; |
| |
| p0 = a0 * onebyfftLen; |
| p2 = xt * onebyfftLen; |
| p1 = a1 * onebyfftLen; |
| p3 = yt * onebyfftLen; |
| |
| pSrc[2 * i] = p0; |
| pSrc[2 * i + 1] = p1; |
| pSrc[2 * i + 2] = p2; |
| pSrc[2 * i + 3] = p3; |
| } // butterfly loop end |
| |
| #else /* #if defined (ARM_MATH_DSP) */ |
| |
| n2 = fftLen; |
| |
| // loop for stage |
| for (k = fftLen; k > 2; k = k >> 1) |
| { |
| n1 = n2; |
| n2 = n2 >> 1; |
| ia = 0; |
| |
| // loop for groups |
| j = 0; |
| do |
| { |
| cosVal = pCoef[ia * 2]; |
| sinVal = pCoef[(ia * 2) + 1]; |
| ia = ia + twidCoefModifier; |
| |
| // loop for butterfly |
| i = j; |
| do |
| { |
| l = i + n2; |
| a0 = pSrc[2 * i] + pSrc[2 * l]; |
| xt = pSrc[2 * i] - pSrc[2 * l]; |
| |
| yt = pSrc[2 * i + 1] - pSrc[2 * l + 1]; |
| a1 = pSrc[2 * l + 1] + pSrc[2 * i + 1]; |
| |
| p0 = xt * cosVal; |
| p1 = yt * sinVal; |
| p2 = yt * cosVal; |
| p3 = xt * sinVal; |
| |
| pSrc[2 * i] = a0; |
| pSrc[2 * i + 1] = a1; |
| |
| pSrc[2 * l] = p0 - p1; |
| pSrc[2 * l + 1] = p2 + p3; |
| |
| i += n1; |
| } while ( i < fftLen ); // butterfly loop end |
| j++; |
| } while ( j < n2 ); // groups loop end |
| |
| twidCoefModifier = twidCoefModifier << 1U; |
| } // stages loop end |
| |
| n1 = n2; |
| n2 = n2 >> 1; |
| |
| // loop for butterfly |
| for (i = 0; i < fftLen; i += n1) |
| { |
| l = i + n2; |
| |
| a0 = pSrc[2 * i] + pSrc[2 * l]; |
| xt = pSrc[2 * i] - pSrc[2 * l]; |
| |
| a1 = pSrc[2 * l + 1] + pSrc[2 * i + 1]; |
| yt = pSrc[2 * i + 1] - pSrc[2 * l + 1]; |
| |
| p0 = a0 * onebyfftLen; |
| p2 = xt * onebyfftLen; |
| p1 = a1 * onebyfftLen; |
| p3 = yt * onebyfftLen; |
| |
| pSrc[2 * i] = p0; |
| pSrc[2 * l] = p2; |
| |
| pSrc[2 * i + 1] = p1; |
| pSrc[2 * l + 1] = p3; |
| } // butterfly loop end |
| |
| #endif /* #if defined (ARM_MATH_DSP) */ |
| |
| } |