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;/* ----------------------------------------------------------------------

; * Project:      CMSIS DSP Library

; * Title:        arm_bitreversal2.S

; * Description:  arm_bitreversal_32 function done in assembly for maximum speed.

; *               Called after doing an fft to reorder the output.

; *               The function is loop unrolled by 2. arm_bitreversal_16 as well.

; *

; * $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.

; */

#if   defined ( __CC_ARM )     /* Keil */

    #define CODESECT AREA     ||.text||, CODE, READONLY, ALIGN=2

    #define LABEL

#elif defined ( __IASMARM__ )  /* IAR */

    #define CODESECT SECTION `.text`:CODE

    #define PROC

    #define LABEL

    #define ENDP

    #define EXPORT PUBLIC

#elif defined ( __CSMC__ )	   /* Cosmic */

	#define	CODESECT	switch .text

	#define THUMB

	#define EXPORT	xdef

	#define PROC	:

	#define LABEL	:

	#define ENDP

	#define arm_bitreversal_32 _arm_bitreversal_32

#elif defined ( __TI_ARM__ )   /* TI ARM */

    #define THUMB    .thumb

    #define CODESECT .text

    #define EXPORT   .global

    #define PROC     : .asmfunc

    #define LABEL    :

    #define ENDP     .endasmfunc

    #define END

#elif defined ( __GNUC__ )     /* GCC */

    #define THUMB .thumb

    #define CODESECT .section .text

    #define EXPORT .global

    #define PROC :

    #define LABEL :

    #define ENDP

    #define END

    .syntax unified

#endif

	CODESECT

	THUMB

;/*

;* @brief  In-place bit reversal function.

;* @param[in, out] *pSrc        points to the 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.

;*/

	EXPORT arm_bitreversal_32

	EXPORT arm_bitreversal_16

#if   defined ( __CC_ARM )     /* Keil */

#elif defined ( __IASMARM__ )  /* IAR */

#elif defined ( __CSMC__ )	   /* Cosmic */

#elif defined ( __TI_ARM__ )   /* TI ARM */

#elif defined ( __GNUC__ )     /* GCC */

	.type   arm_bitreversal_16, %function

	.type   arm_bitreversal_32, %function

#endif

#if defined(ARM_MATH_CM0) || defined(ARM_MATH_CM0PLUS) || defined(ARM_MATH_ARMV8MBL)

arm_bitreversal_32 PROC

	ADDS     r3,r1,#1

	PUSH     {r4-r6}

	ADDS     r1,r2,#0

	LSRS     r3,r3,#1

arm_bitreversal_32_0 LABEL

	LDRH     r2,[r1,#2]

	LDRH     r6,[r1,#0]

	ADD      r2,r0,r2

	ADD      r6,r0,r6

	LDR      r5,[r2,#0]

	LDR      r4,[r6,#0]

	STR      r5,[r6,#0]

	STR      r4,[r2,#0]

	LDR      r5,[r2,#4]

	LDR      r4,[r6,#4]

	STR      r5,[r6,#4]

	STR      r4,[r2,#4]

	ADDS     r1,r1,#4

	SUBS     r3,r3,#1

	BNE      arm_bitreversal_32_0

	POP      {r4-r6}

	BX       lr

	ENDP

arm_bitreversal_16 PROC

	ADDS     r3,r1,#1

	PUSH     {r4-r6}

	ADDS     r1,r2,#0

	LSRS     r3,r3,#1

arm_bitreversal_16_0 LABEL

	LDRH     r2,[r1,#2]

	LDRH     r6,[r1,#0]

    LSRS     r2,r2,#1

    LSRS     r6,r6,#1

	ADD      r2,r0,r2

	ADD      r6,r0,r6

	LDR      r5,[r2,#0]

	LDR      r4,[r6,#0]

	STR      r5,[r6,#0]

	STR      r4,[r2,#0]

	ADDS     r1,r1,#4

	SUBS     r3,r3,#1

	BNE      arm_bitreversal_16_0

	POP      {r4-r6}

	BX       lr

	ENDP

#else

arm_bitreversal_32 PROC

	ADDS     r3,r1,#1

	CMP      r3,#1

	IT       LS

	BXLS     lr

	PUSH     {r4-r9}

	ADDS     r1,r2,#2

	LSRS     r3,r3,#2

arm_bitreversal_32_0 LABEL       ;/* loop unrolled by 2 */

	LDRH     r8,[r1,#4]

	LDRH     r9,[r1,#2]

	LDRH     r2,[r1,#0]

	LDRH     r12,[r1,#-2]

	ADD      r8,r0,r8

	ADD      r9,r0,r9

	ADD      r2,r0,r2

	ADD      r12,r0,r12

	LDR      r7,[r9,#0]

	LDR      r6,[r8,#0]

	LDR      r5,[r2,#0]

	LDR      r4,[r12,#0]

	STR      r6,[r9,#0]

	STR      r7,[r8,#0]

	STR      r5,[r12,#0]

	STR      r4,[r2,#0]

	LDR      r7,[r9,#4]

	LDR      r6,[r8,#4]

	LDR      r5,[r2,#4]

	LDR      r4,[r12,#4]

	STR      r6,[r9,#4]

	STR      r7,[r8,#4]

	STR      r5,[r12,#4]

	STR      r4,[r2,#4]

	ADDS     r1,r1,#8

	SUBS     r3,r3,#1

	BNE      arm_bitreversal_32_0

	POP      {r4-r9}

	BX       lr

	ENDP

arm_bitreversal_16 PROC

	ADDS     r3,r1,#1

	CMP      r3,#1

	IT       LS

	BXLS     lr

	PUSH     {r4-r9}

	ADDS     r1,r2,#2

	LSRS     r3,r3,#2

arm_bitreversal_16_0 LABEL       ;/* loop unrolled by 2 */

	LDRH     r8,[r1,#4]

	LDRH     r9,[r1,#2]

	LDRH     r2,[r1,#0]

	LDRH     r12,[r1,#-2]

	ADD      r8,r0,r8,LSR #1

	ADD      r9,r0,r9,LSR #1

	ADD      r2,r0,r2,LSR #1

	ADD      r12,r0,r12,LSR #1

	LDR      r7,[r9,#0]

	LDR      r6,[r8,#0]

	LDR      r5,[r2,#0]

	LDR      r4,[r12,#0]

	STR      r6,[r9,#0]

	STR      r7,[r8,#0]

	STR      r5,[r12,#0]

	STR      r4,[r2,#0]

	ADDS     r1,r1,#8

	SUBS     r3,r3,#1

	BNE      arm_bitreversal_16_0

	POP      {r4-r9}

	BX       lr

	ENDP

#endif

	END