230 lines
7 KiB
C
230 lines
7 KiB
C
/* ----------------------------------------------------------------------
|
|
* Project: CMSIS DSP Library
|
|
* Title: arm_bitreversal.c
|
|
* Description: Bitreversal functions
|
|
*
|
|
* $Date: 27. January 2017
|
|
* $Revision: V.1.5.1
|
|
*
|
|
* Target Processor: Cortex-M cores
|
|
* -------------------------------------------------------------------- */
|
|
/*
|
|
* Copyright (C) 2010-2017 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"
|
|
#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;
|
|
}
|
|
}
|