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