;/* | |
; FreeRTOS V6.0.5 - Copyright (C) 2010 Real Time Engineers Ltd. | |
; | |
; *************************************************************************** | |
; * * | |
; * If you are: * | |
; * * | |
; * + New to FreeRTOS, * | |
; * + Wanting to learn FreeRTOS or multitasking in general quickly * | |
; * + Looking for basic training, * | |
; * + Wanting to improve your FreeRTOS skills and productivity * | |
; * * | |
; * then take a look at the FreeRTOS eBook * | |
; * * | |
; * "Using the FreeRTOS Real Time Kernel - a Practical Guide" * | |
; * http://www.FreeRTOS.org/Documentation * | |
; * * | |
; * A pdf reference manual is also available. Both are usually delivered * | |
; * to your inbox within 20 minutes to two hours when purchased between 8am * | |
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; *************************************************************************** | |
; | |
; 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 (version 2) as published by the | |
; Free Software Foundation AND MODIFIED BY the FreeRTOS exception. | |
; ***NOTE*** The exception to the GPL is included to allow you to distribute | |
; a combined work that includes FreeRTOS without being obliged to provide the | |
; source code for proprietary components outside of the FreeRTOS kernel. | |
; 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 and the FreeRTOS license exception along with FreeRTOS; if not it | |
; can be viewed here: http://www.freertos.org/a00114.html and also obtained | |
; by writing to Richard Barry, contact details for whom are available on the | |
; FreeRTOS WEB site. | |
; | |
; 1 tab == 4 spaces! | |
; | |
; 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 | |