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
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
|
/*
ChibiOS/RT - Copyright (C) 2006,2007,2008,2009,2010 Giovanni Di Sirio.
This file is part of ChibiOS/RT.
ChibiOS/RT is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
ChibiOS/RT 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
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
/*
* Imports the Cortex-Mx parameters header and performs the same calculations
* done in chcore.h.
*/
#include "cmparams.h"
#define CORTEX_PRIORITY_MASK(n) ((n) << (8 - CORTEX_PRIORITY_BITS))
EXTCTX_SIZE EQU 32
CONTEXT_OFFSET EQU 12
PRESERVE8
THUMB
AREA |.text|, CODE, READONLY
IMPORT chThdExit
IMPORT chSchIsRescRequiredExI
IMPORT chSchDoRescheduleI
IMPORT _port_saved_pc
IMPORT _port_irq_nesting
/*
* Performs a context switch between two threads.
*/
EXPORT _port_switch
_port_switch PROC
push {r4, r5, r6, r7, lr}
mov r4, r8
mov r5, r9
mov r6, r10
mov r7, r11
push {r4, r5, r6, r7}
mov r3, sp
str r3, [r1, #CONTEXT_OFFSET]
ldr r3, [r0, #CONTEXT_OFFSET]
mov sp, r3
pop {r4, r5, r6, r7}
mov r8, r4
mov r9, r5
mov r10, r6
mov r11, r7
pop {r4, r5, r6, r7, pc}
ENDP
/*
* Start a thread by invoking its work function.
* If the work function returns @p chThdExit() is automatically invoked.
*/
EXPORT _port_thread_start
_port_thread_start PROC
cpsie i
mov r0, r5
blx r4
bl chThdExit
ENDP
/*
* Post-IRQ switch code.
* Exception handlers return here for context switching.
*/
EXPORT _port_switch_from_isr
_port_switch_from_isr PROC
/* Note, saves r4 to make space for the PC.*/
push {r0, r1, r2, r3, r4}
mrs r0, APSR
mov r1, r12
push {r0, r1, lr}
ldr r0, =_port_saved_pc
ldr r0, [r0]
adds r0, r0, #1
str r0, [sp, #28]
bl chSchDoRescheduleI
pop {r0, r1, r2}
mov r12, r1
msr APSR, r0
mov lr, r2
pop {r0, r1, r2, r3}
cpsie i
pop {pc}
ENDP
/*
* Reschedule verification and setup after an IRQ.
*/
EXPORT _port_irq_epilogue
_port_irq_epilogue PROC
push {r4, lr}
cpsid i
ldr r2, =_port_irq_nesting
ldr r3, [r2]
subs r3, r3, #1
str r3, [r2]
cmp r3, #0
beq skipexit
notrequired
cpsie i
pop {r4, pc}
skipexit
bl chSchIsRescRequiredExI
cmp r0, #0
beq notrequired
mrs r1, PSP
ldr r2, =_port_saved_pc
ldr r3, [r1, #24]
str r3, [r2]
ldr r3, =_port_switch_from_isr
str r3, [r1, #24]
pop {r4, pc}
nop
ENDP
END
|