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132 lines
4.8 KiB
C
132 lines
4.8 KiB
C
/*
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FreeRTOS V6.0.1 - Copyright (C) 2009 Real Time Engineers Ltd.
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***************************************************************************
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* *
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* If you are: *
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* *
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* + New to FreeRTOS, *
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* + Wanting to learn FreeRTOS or multitasking in general quickly *
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* + Looking for basic training, *
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* + Wanting to improve your FreeRTOS skills and productivity *
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* *
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* then take a look at the FreeRTOS eBook *
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* *
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* "Using the FreeRTOS Real Time Kernel - a Practical Guide" *
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* http://www.FreeRTOS.org/Documentation *
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* *
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* A pdf reference manual is also available. Both are usually delivered *
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* to your inbox within 20 minutes to two hours when purchased between 8am *
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* and 8pm GMT (although please allow up to 24 hours in case of *
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* exceptional circumstances). Thank you for your support! *
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* *
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***************************************************************************
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This file is part of the FreeRTOS distribution.
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FreeRTOS is free software; you can redistribute it and/or modify it under
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the terms of the GNU General Public License (version 2) as published by the
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Free Software Foundation AND MODIFIED BY the FreeRTOS exception.
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***NOTE*** The exception to the GPL is included to allow you to distribute
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a combined work that includes FreeRTOS without being obliged to provide the
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source code for proprietary components outside of the FreeRTOS kernel.
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FreeRTOS is distributed in the hope that it will be useful, but WITHOUT
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ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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more details. You should have received a copy of the GNU General Public
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License and the FreeRTOS license exception along with FreeRTOS; if not it
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can be viewed here: http://www.freertos.org/a00114.html and also obtained
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by writing to Richard Barry, contact details for whom are available on the
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FreeRTOS WEB site.
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1 tab == 4 spaces!
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http://www.FreeRTOS.org - Documentation, latest information, license and
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contact details.
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http://www.SafeRTOS.com - A version that is certified for use in safety
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critical systems.
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http://www.OpenRTOS.com - Commercial support, development, porting,
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licensing and training services.
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*/
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EXTERN pxCurrentTCB
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EXTERN ulCriticalNesting
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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; Context save and restore macro definitions
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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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; Push the return address onto the stack.
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STMDB R0!, {LR}
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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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; Pop R0 so we can save it onto the system mode stack.
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LDMIA SP!, {R0}
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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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; 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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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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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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; 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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; 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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; 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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; Restore the return address.
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LDR LR, [LR, #+60]
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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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ENDM
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