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/*
FreeRTOS.org V5.1.2 - Copyright (C) 2003-2009 Richard Barry.
This file is part of the FreeRTOS distribution.
FreeRTOS is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
FreeRTOS is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with FreeRTOS; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
A special exception to the GPL can be applied should you wish to distribute
a combined work that includes FreeRTOS, without being obliged to provide
the source code for any proprietary components. See the licensing section
of http://www.FreeRTOS.org for full details of how and when the exception
can be applied.
***************************************************************************
***************************************************************************
* *
* Get the FreeRTOS eBook! See http://www.FreeRTOS.org/Documentation *
* *
* This is a concise, step by step, 'hands on' guide that describes both *
* general multitasking concepts and FreeRTOS specifics. It presents and *
* explains numerous examples that are written using the FreeRTOS API. *
* Full source code for all the examples is provided in an accompanying *
* .zip file. *
* *
***************************************************************************
***************************************************************************
Please ensure to read the configuration and relevant port sections of the
online documentation.
http://www.FreeRTOS.org - Documentation, latest information, license and
contact details.
http://www.SafeRTOS.com - A version that is certified for use in safety
critical systems.
http://www.OpenRTOS.com - Commercial support, development, porting,
licensing and training services.
*/
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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