| 1 |
572 |
jeremybenn |
/*
|
| 2 |
|
|
FreeRTOS V6.1.1 - Copyright (C) 2011 Real Time Engineers Ltd.
|
| 3 |
|
|
|
| 4 |
|
|
***************************************************************************
|
| 5 |
|
|
* *
|
| 6 |
|
|
* If you are: *
|
| 7 |
|
|
* *
|
| 8 |
|
|
* + New to FreeRTOS, *
|
| 9 |
|
|
* + Wanting to learn FreeRTOS or multitasking in general quickly *
|
| 10 |
|
|
* + Looking for basic training, *
|
| 11 |
|
|
* + Wanting to improve your FreeRTOS skills and productivity *
|
| 12 |
|
|
* *
|
| 13 |
|
|
* then take a look at the FreeRTOS books - available as PDF or paperback *
|
| 14 |
|
|
* *
|
| 15 |
|
|
* "Using the FreeRTOS Real Time Kernel - a Practical Guide" *
|
| 16 |
|
|
* http://www.FreeRTOS.org/Documentation *
|
| 17 |
|
|
* *
|
| 18 |
|
|
* A pdf reference manual is also available. Both are usually delivered *
|
| 19 |
|
|
* to your inbox within 20 minutes to two hours when purchased between 8am *
|
| 20 |
|
|
* and 8pm GMT (although please allow up to 24 hours in case of *
|
| 21 |
|
|
* exceptional circumstances). Thank you for your support! *
|
| 22 |
|
|
* *
|
| 23 |
|
|
***************************************************************************
|
| 24 |
|
|
|
| 25 |
|
|
This file is part of the FreeRTOS distribution.
|
| 26 |
|
|
|
| 27 |
|
|
FreeRTOS is free software; you can redistribute it and/or modify it under
|
| 28 |
|
|
the terms of the GNU General Public License (version 2) as published by the
|
| 29 |
|
|
Free Software Foundation AND MODIFIED BY the FreeRTOS exception.
|
| 30 |
|
|
***NOTE*** The exception to the GPL is included to allow you to distribute
|
| 31 |
|
|
a combined work that includes FreeRTOS without being obliged to provide the
|
| 32 |
|
|
source code for proprietary components outside of the FreeRTOS kernel.
|
| 33 |
|
|
FreeRTOS is distributed in the hope that it will be useful, but WITHOUT
|
| 34 |
|
|
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
|
| 35 |
|
|
FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
|
| 36 |
|
|
more details. You should have received a copy of the GNU General Public
|
| 37 |
|
|
License and the FreeRTOS license exception along with FreeRTOS; if not it
|
| 38 |
|
|
can be viewed here: http://www.freertos.org/a00114.html and also obtained
|
| 39 |
|
|
by writing to Richard Barry, contact details for whom are available on the
|
| 40 |
|
|
FreeRTOS WEB site.
|
| 41 |
|
|
|
| 42 |
|
|
1 tab == 4 spaces!
|
| 43 |
|
|
|
| 44 |
|
|
http://www.FreeRTOS.org - Documentation, latest information, license and
|
| 45 |
|
|
contact details.
|
| 46 |
|
|
|
| 47 |
|
|
http://www.SafeRTOS.com - A version that is certified for use in safety
|
| 48 |
|
|
critical systems.
|
| 49 |
|
|
|
| 50 |
|
|
http://www.OpenRTOS.com - Commercial support, development, porting,
|
| 51 |
|
|
licensing and training services.
|
| 52 |
|
|
*/
|
| 53 |
|
|
|
| 54 |
|
|
EXTERN pxCurrentTCB
|
| 55 |
|
|
EXTERN ulCriticalNesting
|
| 56 |
|
|
|
| 57 |
|
|
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
|
| 58 |
|
|
; Context save and restore macro definitions
|
| 59 |
|
|
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
|
| 60 |
|
|
|
| 61 |
|
|
portSAVE_CONTEXT MACRO
|
| 62 |
|
|
|
| 63 |
|
|
; Push R0 as we are going to use the register.
|
| 64 |
|
|
STMDB SP!, {R0}
|
| 65 |
|
|
|
| 66 |
|
|
; Set R0 to point to the task stack pointer.
|
| 67 |
|
|
STMDB SP, {SP}^
|
| 68 |
|
|
NOP
|
| 69 |
|
|
SUB SP, SP, #4
|
| 70 |
|
|
LDMIA SP!, {R0}
|
| 71 |
|
|
|
| 72 |
|
|
; Push the return address onto the stack.
|
| 73 |
|
|
STMDB R0!, {LR}
|
| 74 |
|
|
|
| 75 |
|
|
; Now we have saved LR we can use it instead of R0.
|
| 76 |
|
|
MOV LR, R0
|
| 77 |
|
|
|
| 78 |
|
|
; Pop R0 so we can save it onto the system mode stack.
|
| 79 |
|
|
LDMIA SP!, {R0}
|
| 80 |
|
|
|
| 81 |
|
|
; Push all the system mode registers onto the task stack.
|
| 82 |
|
|
STMDB LR, {R0-LR}^
|
| 83 |
|
|
NOP
|
| 84 |
|
|
SUB LR, LR, #60
|
| 85 |
|
|
|
| 86 |
|
|
; Push the SPSR onto the task stack.
|
| 87 |
|
|
MRS R0, SPSR
|
| 88 |
|
|
STMDB LR!, {R0}
|
| 89 |
|
|
|
| 90 |
|
|
LDR R0, =ulCriticalNesting
|
| 91 |
|
|
LDR R0, [R0]
|
| 92 |
|
|
STMDB LR!, {R0}
|
| 93 |
|
|
|
| 94 |
|
|
; Store the new top of stack for the task.
|
| 95 |
|
|
LDR R1, =pxCurrentTCB
|
| 96 |
|
|
LDR R0, [R1]
|
| 97 |
|
|
STR LR, [R0]
|
| 98 |
|
|
|
| 99 |
|
|
ENDM
|
| 100 |
|
|
|
| 101 |
|
|
|
| 102 |
|
|
portRESTORE_CONTEXT MACRO
|
| 103 |
|
|
|
| 104 |
|
|
; Set the LR to the task stack.
|
| 105 |
|
|
LDR R1, =pxCurrentTCB
|
| 106 |
|
|
LDR R0, [R1]
|
| 107 |
|
|
LDR LR, [R0]
|
| 108 |
|
|
|
| 109 |
|
|
; The critical nesting depth is the first item on the stack.
|
| 110 |
|
|
; Load it into the ulCriticalNesting variable.
|
| 111 |
|
|
LDR R0, =ulCriticalNesting
|
| 112 |
|
|
LDMFD LR!, {R1}
|
| 113 |
|
|
STR R1, [R0]
|
| 114 |
|
|
|
| 115 |
|
|
; Get the SPSR from the stack.
|
| 116 |
|
|
LDMFD LR!, {R0}
|
| 117 |
|
|
MSR SPSR_cxsf, R0
|
| 118 |
|
|
|
| 119 |
|
|
; Restore all system mode registers for the task.
|
| 120 |
|
|
LDMFD LR, {R0-R14}^
|
| 121 |
|
|
NOP
|
| 122 |
|
|
|
| 123 |
|
|
; Restore the return address.
|
| 124 |
|
|
LDR LR, [LR, #+60]
|
| 125 |
|
|
|
| 126 |
|
|
; And return - correcting the offset in the LR to obtain the
|
| 127 |
|
|
; correct address.
|
| 128 |
|
|
SUBS PC, LR, #4
|
| 129 |
|
|
|
| 130 |
|
|
ENDM
|
| 131 |
|
|
|
