| /* ---------------------------------------------------------------------- |
| * Copyright (C) 2010-2014 ARM Limited. All rights reserved. |
| * |
| * $Date: 19. March 2015 |
| * $Revision: V.1.4.5 |
| * |
| * Project: CMSIS DSP Library |
| * Title: arm_bitreversal.c |
| * |
| * Description: This file has common tables like Bitreverse, reciprocal etc which are used across different functions |
| * |
| * 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" |
| #include "arm_common_tables.h" |
| |
| /* |
| * @brief In-place bit reversal function. |
| * @param[in, out] *pSrc points to the in-place buffer of floating-point data type. |
| * @param[in] fftSize length of the FFT. |
| * @param[in] bitRevFactor bit reversal modifier that supports different size FFTs with the same bit reversal table. |
| * @param[in] *pBitRevTab points to the bit reversal table. |
| * @return none. |
| */ |
| |
| void arm_bitreversal_f32( |
| float32_t * pSrc, |
| uint16_t fftSize, |
| uint16_t bitRevFactor, |
| uint16_t * pBitRevTab) |
| { |
| uint16_t fftLenBy2, fftLenBy2p1; |
| uint16_t i, j; |
| float32_t in; |
| |
| /* Initializations */ |
| j = 0u; |
| fftLenBy2 = fftSize >> 1u; |
| fftLenBy2p1 = (fftSize >> 1u) + 1u; |
| |
| /* Bit Reversal Implementation */ |
| for (i = 0u; i <= (fftLenBy2 - 2u); i += 2u) |
| { |
| if(i < j) |
| { |
| /* pSrc[i] <-> pSrc[j]; */ |
| in = pSrc[2u * i]; |
| pSrc[2u * i] = pSrc[2u * j]; |
| pSrc[2u * j] = in; |
| |
| /* pSrc[i+1u] <-> pSrc[j+1u] */ |
| in = pSrc[(2u * i) + 1u]; |
| pSrc[(2u * i) + 1u] = pSrc[(2u * j) + 1u]; |
| pSrc[(2u * j) + 1u] = in; |
| |
| /* pSrc[i+fftLenBy2p1] <-> pSrc[j+fftLenBy2p1] */ |
| in = pSrc[2u * (i + fftLenBy2p1)]; |
| pSrc[2u * (i + fftLenBy2p1)] = pSrc[2u * (j + fftLenBy2p1)]; |
| pSrc[2u * (j + fftLenBy2p1)] = in; |
| |
| /* pSrc[i+fftLenBy2p1+1u] <-> pSrc[j+fftLenBy2p1+1u] */ |
| in = pSrc[(2u * (i + fftLenBy2p1)) + 1u]; |
| pSrc[(2u * (i + fftLenBy2p1)) + 1u] = |
| pSrc[(2u * (j + fftLenBy2p1)) + 1u]; |
| pSrc[(2u * (j + fftLenBy2p1)) + 1u] = in; |
| |
| } |
| |
| /* pSrc[i+1u] <-> pSrc[j+1u] */ |
| in = pSrc[2u * (i + 1u)]; |
| pSrc[2u * (i + 1u)] = pSrc[2u * (j + fftLenBy2)]; |
| pSrc[2u * (j + fftLenBy2)] = in; |
| |
| /* pSrc[i+2u] <-> pSrc[j+2u] */ |
| in = pSrc[(2u * (i + 1u)) + 1u]; |
| pSrc[(2u * (i + 1u)) + 1u] = pSrc[(2u * (j + fftLenBy2)) + 1u]; |
| pSrc[(2u * (j + fftLenBy2)) + 1u] = in; |
| |
| /* Reading the index for the bit reversal */ |
| j = *pBitRevTab; |
| |
| /* Updating the bit reversal index depending on the fft length */ |
| pBitRevTab += bitRevFactor; |
| } |
| } |
| |
| |
| |
| /* |
| * @brief In-place bit reversal function. |
| * @param[in, out] *pSrc points to the in-place buffer of Q31 data type. |
| * @param[in] fftLen length of the FFT. |
| * @param[in] bitRevFactor bit reversal modifier that supports different size FFTs with the same bit reversal table |
| * @param[in] *pBitRevTab points to bit reversal table. |
| * @return none. |
| */ |
| |
| void arm_bitreversal_q31( |
| q31_t * pSrc, |
| uint32_t fftLen, |
| uint16_t bitRevFactor, |
| uint16_t * pBitRevTable) |
| { |
| uint32_t fftLenBy2, fftLenBy2p1, i, j; |
| q31_t in; |
| |
| /* Initializations */ |
| j = 0u; |
| fftLenBy2 = fftLen / 2u; |
| fftLenBy2p1 = (fftLen / 2u) + 1u; |
| |
| /* Bit Reversal Implementation */ |
| for (i = 0u; i <= (fftLenBy2 - 2u); i += 2u) |
| { |
| if(i < j) |
| { |
| /* pSrc[i] <-> pSrc[j]; */ |
| in = pSrc[2u * i]; |
| pSrc[2u * i] = pSrc[2u * j]; |
| pSrc[2u * j] = in; |
| |
| /* pSrc[i+1u] <-> pSrc[j+1u] */ |
| in = pSrc[(2u * i) + 1u]; |
| pSrc[(2u * i) + 1u] = pSrc[(2u * j) + 1u]; |
| pSrc[(2u * j) + 1u] = in; |
| |
| /* pSrc[i+fftLenBy2p1] <-> pSrc[j+fftLenBy2p1] */ |
| in = pSrc[2u * (i + fftLenBy2p1)]; |
| pSrc[2u * (i + fftLenBy2p1)] = pSrc[2u * (j + fftLenBy2p1)]; |
| pSrc[2u * (j + fftLenBy2p1)] = in; |
| |
| /* pSrc[i+fftLenBy2p1+1u] <-> pSrc[j+fftLenBy2p1+1u] */ |
| in = pSrc[(2u * (i + fftLenBy2p1)) + 1u]; |
| pSrc[(2u * (i + fftLenBy2p1)) + 1u] = |
| pSrc[(2u * (j + fftLenBy2p1)) + 1u]; |
| pSrc[(2u * (j + fftLenBy2p1)) + 1u] = in; |
| |
| } |
| |
| /* pSrc[i+1u] <-> pSrc[j+1u] */ |
| in = pSrc[2u * (i + 1u)]; |
| pSrc[2u * (i + 1u)] = pSrc[2u * (j + fftLenBy2)]; |
| pSrc[2u * (j + fftLenBy2)] = in; |
| |
| /* pSrc[i+2u] <-> pSrc[j+2u] */ |
| in = pSrc[(2u * (i + 1u)) + 1u]; |
| pSrc[(2u * (i + 1u)) + 1u] = pSrc[(2u * (j + fftLenBy2)) + 1u]; |
| pSrc[(2u * (j + fftLenBy2)) + 1u] = in; |
| |
| /* Reading the index for the bit reversal */ |
| j = *pBitRevTable; |
| |
| /* Updating the bit reversal index depending on the fft length */ |
| pBitRevTable += bitRevFactor; |
| } |
| } |
| |
| |
| |
| /* |
| * @brief In-place bit reversal function. |
| * @param[in, out] *pSrc points to the in-place buffer of Q15 data type. |
| * @param[in] fftLen length of the FFT. |
| * @param[in] bitRevFactor bit reversal modifier that supports different size FFTs with the same bit reversal table |
| * @param[in] *pBitRevTab points to bit reversal table. |
| * @return none. |
| */ |
| |
| void arm_bitreversal_q15( |
| q15_t * pSrc16, |
| uint32_t fftLen, |
| uint16_t bitRevFactor, |
| uint16_t * pBitRevTab) |
| { |
| q31_t *pSrc = (q31_t *) pSrc16; |
| q31_t in; |
| uint32_t fftLenBy2, fftLenBy2p1; |
| uint32_t i, j; |
| |
| /* Initializations */ |
| j = 0u; |
| fftLenBy2 = fftLen / 2u; |
| fftLenBy2p1 = (fftLen / 2u) + 1u; |
| |
| /* Bit Reversal Implementation */ |
| for (i = 0u; i <= (fftLenBy2 - 2u); i += 2u) |
| { |
| if(i < j) |
| { |
| /* pSrc[i] <-> pSrc[j]; */ |
| /* pSrc[i+1u] <-> pSrc[j+1u] */ |
| in = pSrc[i]; |
| pSrc[i] = pSrc[j]; |
| pSrc[j] = in; |
| |
| /* pSrc[i + fftLenBy2p1] <-> pSrc[j + fftLenBy2p1]; */ |
| /* pSrc[i + fftLenBy2p1+1u] <-> pSrc[j + fftLenBy2p1+1u] */ |
| in = pSrc[i + fftLenBy2p1]; |
| pSrc[i + fftLenBy2p1] = pSrc[j + fftLenBy2p1]; |
| pSrc[j + fftLenBy2p1] = in; |
| } |
| |
| /* pSrc[i+1u] <-> pSrc[j+fftLenBy2]; */ |
| /* pSrc[i+2] <-> pSrc[j+fftLenBy2+1u] */ |
| in = pSrc[i + 1u]; |
| pSrc[i + 1u] = pSrc[j + fftLenBy2]; |
| pSrc[j + fftLenBy2] = in; |
| |
| /* Reading the index for the bit reversal */ |
| j = *pBitRevTab; |
| |
| /* Updating the bit reversal index depending on the fft length */ |
| pBitRevTab += bitRevFactor; |
| } |
| } |
