1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
|
;/*
; * FreeRTOS Kernel V10.4.3 LTS Patch 2
; * Copyright (C) 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
; *
; * Permission is hereby granted, free of charge, to any person obtaining a copy of
; * this software and associated documentation files (the "Software"), to deal in
; * the Software without restriction, including without limitation the rights to
; * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
; * the Software, and to permit persons to whom the Software is furnished to do so,
; * subject to the following conditions:
; *
; * The above copyright notice and this permission notice shall be included in all
; * copies or substantial portions of the Software.
; *
; * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
; * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
; * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
; * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
; * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
; * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
; *
; * https://www.FreeRTOS.org
; * https://github.com/FreeRTOS
; *
; * 1 tab == 4 spaces!
; */
IMPORT ulCriticalNesting ;
IMPORT pxCurrentTCB ;
MACRO
portRESTORE_CONTEXT
LDR R0, =pxCurrentTCB ; Set the LR to the task stack. The location was...
LDR R0, [R0] ; ... stored in pxCurrentTCB
LDR LR, [R0]
LDR R0, =ulCriticalNesting ; The critical nesting depth is the first item on...
LDMFD LR!, {R1} ; ...the stack. Load it into the ulCriticalNesting var.
STR R1, [R0] ;
LDMFD LR!, {R0} ; Get the SPSR from the stack.
MSR SPSR_cxsf, R0 ;
LDMFD LR, {R0-R14}^ ; Restore all system mode registers for the task.
NOP ;
LDR LR, [LR, #+60] ; Restore the return address
; And return - correcting the offset in the LR to obtain ...
SUBS PC, LR, #4 ; ...the correct address.
MEND
; /**********************************************************************/
MACRO
portSAVE_CONTEXT
STMDB SP!, {R0} ; Store R0 first as we need to use it.
STMDB SP,{SP}^ ; Set R0 to point to the task stack pointer.
NOP ;
SUB SP, SP, #4 ;
LDMIA SP!,{R0} ;
STMDB R0!, {LR} ; Push the return address onto the stack.
MOV LR, R0 ; Now we have saved LR we can use it instead of R0.
LDMIA SP!, {R0} ; Pop R0 so we can save it onto the system mode stack.
STMDB LR,{R0-LR}^ ; Push all the system mode registers onto the task stack.
NOP ;
SUB LR, LR, #60 ;
MRS R0, SPSR ; Push the SPSR onto the task stack.
STMDB LR!, {R0} ;
LDR R0, =ulCriticalNesting ;
LDR R0, [R0] ;
STMDB LR!, {R0} ;
LDR R0, =pxCurrentTCB ; Store the new top of stack for the task.
LDR R1, [R0] ;
STR LR, [R1] ;
MEND
END
|
