| /* ---------------------------------------------------------------------- |
| * Copyright (C) 2010-2014 ARM Limited. All rights reserved. |
| * |
| * $Date: 19. March 2015 |
| * $Revision: V.1.4.5 |
| * |
| * Project: CMSIS DSP Library |
| * Title: arm_cfft_radix2_f32.c |
| * |
| * Description: Radix-2 Decimation in Frequency CFFT & CIFFT Floating point processing function |
| * |
| * |
| * Target Processor: Cortex-M4/Cortex-M3/Cortex-M0 |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * - Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * - Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in |
| * the documentation and/or other materials provided with the |
| * distribution. |
| * - Neither the name of ARM LIMITED nor the names of its contributors |
| * may be used to endorse or promote products derived from this |
| * software without specific prior written permission. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS |
| * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE |
| * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, |
| * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, |
| * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; |
| * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER |
| * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
| * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN |
| * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
| * POSSIBILITY OF SUCH DAMAGE. |
| * -------------------------------------------------------------------- */ |
| |
| #include "arm_math.h" |
| |
| void arm_radix2_butterfly_f32( |
| float32_t * pSrc, |
| uint32_t fftLen, |
| float32_t * pCoef, |
| uint16_t twidCoefModifier); |
| |
| void arm_radix2_butterfly_inverse_f32( |
| float32_t * pSrc, |
| uint32_t fftLen, |
| float32_t * pCoef, |
| uint16_t twidCoefModifier, |
| float32_t onebyfftLen); |
| |
| extern void arm_bitreversal_f32( |
| float32_t * pSrc, |
| uint16_t fftSize, |
| uint16_t bitRevFactor, |
| uint16_t * pBitRevTab); |
| |
| /** |
| * @ingroup groupTransforms |
| */ |
| |
| /** |
| * @addtogroup ComplexFFT |
| * @{ |
| */ |
| |
| /** |
| * @details |
| * @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 the in-place buffer of floating-point data type. |
| * @param[in] fftLen length of the FFT. |
| * @param[in] *pCoef points to the 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, |
| 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; |
| |
| #ifndef ARM_MATH_CM0_FAMILY |
| |
| /* 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 |
| |
| 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 // #ifndef ARM_MATH_CM0_FAMILY |
| |
| } |
| |
| |
| void arm_radix2_butterfly_inverse_f32( |
| float32_t * pSrc, |
| uint32_t fftLen, |
| 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; |
| |
| #ifndef ARM_MATH_CM0_FAMILY |
| |
| 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 |
| |
| 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[2u * l] = p2; |
| |
| pSrc[2 * i + 1] = p1; |
| pSrc[2u * l + 1u] = p3; |
| } // butterfly loop end |
| |
| #endif // #ifndef ARM_MATH_CM0_FAMILY |
| |
| } |
