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jeremybenn |
;/*
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; FreeRTOS V6.1.1 - Copyright (C) 2011 Real Time Engineers Ltd.
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;
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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 books - available as PDF or paperback *
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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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;
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; This file is part of the FreeRTOS distribution.
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;
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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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;
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; 1 tab == 4 spaces!
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;
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; http://www.FreeRTOS.org - Documentation, latest information, license and
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; contact details.
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;
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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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;
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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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IMPORT ulCriticalNesting ;
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IMPORT pxCurrentTCB ;
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MACRO
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portRESTORE_CONTEXT
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LDR R0, =pxCurrentTCB ; Set the LR to the task stack. The location was...
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LDR R0, [R0] ; ... stored in pxCurrentTCB
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LDR LR, [R0]
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LDR R0, =ulCriticalNesting ; The critical nesting depth is the first item on...
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LDMFD LR!, {R1} ; ...the stack. Load it into the ulCriticalNesting var.
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STR R1, [R0] ;
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LDMFD LR!, {R0} ; Get the SPSR from the stack.
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MSR SPSR_cxsf, R0 ;
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LDMFD LR, {R0-R14}^ ; Restore all system mode registers for the task.
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NOP ;
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LDR LR, [LR, #+60] ; Restore the return address
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; And return - correcting the offset in the LR to obtain ...
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SUBS PC, LR, #4 ; ...the correct address.
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MEND
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; /**********************************************************************/
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MACRO
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portSAVE_CONTEXT
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STMDB SP!, {R0} ; Store R0 first as we need to use it.
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STMDB SP,{SP}^ ; Set R0 to point to the task stack pointer.
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NOP ;
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SUB SP, SP, #4 ;
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LDMIA SP!,{R0} ;
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STMDB R0!, {LR} ; Push the return address onto the stack.
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MOV LR, R0 ; Now we have saved LR we can use it instead of R0.
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LDMIA SP!, {R0} ; Pop R0 so we can save it onto the system mode stack.
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STMDB LR,{R0-LR}^ ; Push all the system mode registers onto the task stack.
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NOP ;
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SUB LR, LR, #60 ;
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MRS R0, SPSR ; Push the SPSR onto the task stack.
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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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LDR R0, =pxCurrentTCB ; Store the new top of stack for the task.
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LDR R1, [R0] ;
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STR LR, [R1] ;
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MEND
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END
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