100 lines
2.4 KiB
C
100 lines
2.4 KiB
C
/* ----------------------------------------------------------------------
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* Project: CMSIS DSP Library
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* Title: arm_bitreversal2.c
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* Description: Bitreversal functions
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*
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* $Date: 18. March 2019
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* $Revision: V1.0.0
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*
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* Target Processor: Cortex-M cores
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* -------------------------------------------------------------------- */
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/*
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* Copyright (C) 2019 ARM Limited or its affiliates. All rights reserved.
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*
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* SPDX-License-Identifier: Apache-2.0
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*
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* Licensed under the Apache License, Version 2.0 (the License); you may
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* not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an AS IS BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include "arm_math.h"
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#include "arm_common_tables.h"
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/**
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@brief In-place 32 bit reversal function.
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@param[in,out] pSrc points to in-place buffer of unknown 32-bit data type
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@param[in] bitRevLen bit reversal table length
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@param[in] pBitRevTab points to bit reversal table
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@return none
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*/
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void arm_bitreversal_32(
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uint32_t *pSrc,
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const uint16_t bitRevLen,
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const uint16_t *pBitRevTab)
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{
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uint32_t a, b, i, tmp;
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for (i = 0; i < bitRevLen; )
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{
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a = pBitRevTab[i ] >> 2;
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b = pBitRevTab[i + 1] >> 2;
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//real
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tmp = pSrc[a];
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pSrc[a] = pSrc[b];
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pSrc[b] = tmp;
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//complex
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tmp = pSrc[a+1];
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pSrc[a+1] = pSrc[b+1];
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pSrc[b+1] = tmp;
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i += 2;
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}
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}
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/**
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@brief In-place 16 bit reversal function.
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@param[in,out] pSrc points to in-place buffer of unknown 16-bit data type
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@param[in] bitRevLen bit reversal table length
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@param[in] pBitRevTab points to bit reversal table
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@return none
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*/
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void arm_bitreversal_16(
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uint16_t *pSrc,
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const uint16_t bitRevLen,
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const uint16_t *pBitRevTab)
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{
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uint16_t a, b, i, tmp;
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for (i = 0; i < bitRevLen; )
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{
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a = pBitRevTab[i ] >> 2;
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b = pBitRevTab[i + 1] >> 2;
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//real
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tmp = pSrc[a];
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pSrc[a] = pSrc[b];
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pSrc[b] = tmp;
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//complex
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tmp = pSrc[a+1];
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pSrc[a+1] = pSrc[b+1];
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pSrc[b+1] = tmp;
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i += 2;
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}
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}
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