;/* ----------------------------------------------------------------------
; * 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: 18. March 2019
; * $Revision: V1.5.2
; *
; * Target Processor: Cortex-M cores
; * -------------------------------------------------------------------- */
;/*
; * Copyright (C) 2010-2019 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.
; */
#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_FAMILY)
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
