| /* ---------------------------------------------------------------------- |
| * 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; |
| } |
| } |