pinebuds/platform/cmsis/DSP_Lib/TransformFunctions/arm_bitreversal2.c

100 lines
2.4 KiB
C

/* ----------------------------------------------------------------------
* Project: CMSIS DSP Library
* Title: arm_bitreversal2.c
* Description: Bitreversal functions
*
* $Date: 18. March 2019
* $Revision: V1.0.0
*
* Target Processor: Cortex-M cores
* -------------------------------------------------------------------- */
/*
* Copyright (C) 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"
#include "arm_common_tables.h"
/**
@brief In-place 32 bit reversal function.
@param[in,out] pSrc points to in-place buffer of unknown 32-bit data type
@param[in] bitRevLen bit reversal table length
@param[in] pBitRevTab points to bit reversal table
@return none
*/
void arm_bitreversal_32(
uint32_t *pSrc,
const uint16_t bitRevLen,
const uint16_t *pBitRevTab)
{
uint32_t a, b, i, tmp;
for (i = 0; i < bitRevLen; )
{
a = pBitRevTab[i ] >> 2;
b = pBitRevTab[i + 1] >> 2;
//real
tmp = pSrc[a];
pSrc[a] = pSrc[b];
pSrc[b] = tmp;
//complex
tmp = pSrc[a+1];
pSrc[a+1] = pSrc[b+1];
pSrc[b+1] = tmp;
i += 2;
}
}
/**
@brief In-place 16 bit reversal function.
@param[in,out] pSrc points to in-place buffer of unknown 16-bit data type
@param[in] bitRevLen bit reversal table length
@param[in] pBitRevTab points to bit reversal table
@return none
*/
void arm_bitreversal_16(
uint16_t *pSrc,
const uint16_t bitRevLen,
const uint16_t *pBitRevTab)
{
uint16_t a, b, i, tmp;
for (i = 0; i < bitRevLen; )
{
a = pBitRevTab[i ] >> 2;
b = pBitRevTab[i + 1] >> 2;
//real
tmp = pSrc[a];
pSrc[a] = pSrc[b];
pSrc[b] = tmp;
//complex
tmp = pSrc[a+1];
pSrc[a+1] = pSrc[b+1];
pSrc[b+1] = tmp;
i += 2;
}
}