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;/*
; * FreeRTOS Kernel <DEVELOPMENT BRANCH>
; * Copyright (C) 2021 Amazon.com, Inc. or its affiliates. All Rights Reserved.
; *
; * SPDX-License-Identifier: MIT
; *
; * Permission is hereby granted, free of charge, to any person obtaining a copy of
; * this software and associated documentation files (the "Software"), to deal in
; * the Software without restriction, including without limitation the rights to
; * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
; * the Software, and to permit persons to whom the Software is furnished to do so,
; * subject to the following conditions:
; *
; * The above copyright notice and this permission notice shall be included in all
; * copies or substantial portions of the Software.
; *
; * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
; * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
; * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
; * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
; * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
; * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
; *
; * https://www.FreeRTOS.org
; * https://github.com/FreeRTOS
; *
; */
EXTERN pxCurrentTCB
EXTERN ulCriticalNesting
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; Context save and restore macro definitions
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
portSAVE_CONTEXT MACRO
; Push R0 as we are going to use the register.
STMDB SP!, {R0}
; Set R0 to point to the task stack pointer.
STMDB SP, {SP}^
NOP
SUB SP, SP, #4
LDMIA SP!, {R0}
; Push the return address onto the stack.
STMDB R0!, {LR}
; Now we have saved LR we can use it instead of R0.
MOV LR, R0
; Pop R0 so we can save it onto the system mode stack.
LDMIA SP!, {R0}
; Push all the system mode registers onto the task stack.
STMDB LR, {R0-LR}^
NOP
SUB LR, LR, #60
; Push the SPSR onto the task stack.
MRS R0, SPSR
STMDB LR!, {R0}
LDR R0, =ulCriticalNesting
LDR R0, [R0]
STMDB LR!, {R0}
; Store the new top of stack for the task.
LDR R1, =pxCurrentTCB
LDR R0, [R1]
STR LR, [R0]
ENDM
portRESTORE_CONTEXT MACRO
; Set the LR to the task stack.
LDR R1, =pxCurrentTCB
LDR R0, [R1]
LDR LR, [R0]
; The critical nesting depth is the first item on the stack.
; Load it into the ulCriticalNesting variable.
LDR R0, =ulCriticalNesting
LDMFD LR!, {R1}
STR R1, [R0]
; Get the SPSR from the stack.
LDMFD LR!, {R0}
MSR SPSR_cxsf, R0
; Restore all system mode registers for the task.
LDMFD LR, {R0-R14}^
NOP
; Restore the return address.
LDR LR, [LR, #+60]
; And return - correcting the offset in the LR to obtain the
; correct address.
SUBS PC, LR, #4
ENDM
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