;/* | |
; * FreeRTOS Kernel V10.3.1 | |
; * Copyright (C) 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved. | |
; * | |
; * Permission is hereby granted, free of charge, to any person obtaining a copy of | |
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; * the Software, and to permit persons to whom the Software is furnished to do so, | |
; * subject to the following conditions: | |
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; * The above copyright notice and this permission notice shall be included in all | |
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; * | |
; * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR | |
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; * http://www.FreeRTOS.org | |
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; * | |
; * 1 tab == 4 spaces! | |
; */ | |
IMPORT ulCriticalNesting ; | |
IMPORT pxCurrentTCB ; | |
MACRO | |
portRESTORE_CONTEXT | |
LDR R0, =pxCurrentTCB ; Set the LR to the task stack. The location was... | |
LDR R0, [R0] ; ... stored in pxCurrentTCB | |
LDR LR, [R0] | |
LDR R0, =ulCriticalNesting ; The critical nesting depth is the first item on... | |
LDMFD LR!, {R1} ; ...the stack. Load it into the ulCriticalNesting var. | |
STR R1, [R0] ; | |
LDMFD LR!, {R0} ; Get the SPSR from the stack. | |
MSR SPSR_cxsf, R0 ; | |
LDMFD LR, {R0-R14}^ ; Restore all system mode registers for the task. | |
NOP ; | |
LDR LR, [LR, #+60] ; Restore the return address | |
; And return - correcting the offset in the LR to obtain ... | |
SUBS PC, LR, #4 ; ...the correct address. | |
MEND | |
; /**********************************************************************/ | |
MACRO | |
portSAVE_CONTEXT | |
STMDB SP!, {R0} ; Store R0 first as we need to use it. | |
STMDB SP,{SP}^ ; Set R0 to point to the task stack pointer. | |
NOP ; | |
SUB SP, SP, #4 ; | |
LDMIA SP!,{R0} ; | |
STMDB R0!, {LR} ; Push the return address onto the stack. | |
MOV LR, R0 ; Now we have saved LR we can use it instead of R0. | |
LDMIA SP!, {R0} ; Pop R0 so we can save it onto the system mode stack. | |
STMDB LR,{R0-LR}^ ; Push all the system mode registers onto the task stack. | |
NOP ; | |
SUB LR, LR, #60 ; | |
MRS R0, SPSR ; Push the SPSR onto the task stack. | |
STMDB LR!, {R0} ; | |
LDR R0, =ulCriticalNesting ; | |
LDR R0, [R0] ; | |
STMDB LR!, {R0} ; | |
LDR R0, =pxCurrentTCB ; Store the new top of stack for the task. | |
LDR R1, [R0] ; | |
STR LR, [R1] ; | |
MEND | |
END |