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
|
.section ".text.exceptions"
.globl svc
svc:
cpsid aif
stmfd sp!, {r0-r12,lr}
ldr r0, [lr, #-4]
bic r0, #0xFF000000
cmp r0, #5
bgt svc_exit
beq svc_000005
cmp r0, #4
beq svc_000004
cmp r0, #3
beq svc_000003
cmp r0, #2
beq svc_000002
cmp r0, #1
beq svc_000001
cmp r0, #0
beq svc_000000
svc_000000:
bl yield
ldmfd sp!, {r0-r12,lr}
b schedule
svc_000001: // Get time
mov r2, #0x3004
movt r2, #0x3F00
ldr r0, [r2, #4] // <- SYS_TIMER_CLO
ldr r1, [r2, #0] // <- SYS_TIMER_CHI
str r0, [sp] // Return value
str r1, [sp, #4] // Return value hi
b svc_exit
svc_000002: // Run Schedule
ldmfd sp!, {r0-r12,lr}
b schedule
svc_000003: // Clean task stack
ldr r3, =scheduler
ldr r2, [r3, #0] // struct Thread* rthread
ldr r1, [r2, #8] // sp_base
cmp r1, #-1
beq svc_exit
ldr r3, =stacks_table
mov r0, #0
strb r0, [r3, r1]
// Free the thread after freeing the stack
mov r0, r2
bl kfree
b svc_exit
svc_000004: // Lock Mutex (usr_r0 = struct Mutex*)
ldr r3, =scheduler
ldr r2, [r3, #0] // struct Thread* rthread
ldr r1, [r2, #0x10] // unsigned long pid
ldr r0, [sp, #0] // struct Mutex* m
add r0, #4 // Point to pid
1: clrex
ldrex r2, [r0, #0]
cmp r2, #0
bne svc_000004_delay_mutex
strexeq r2, r1, [r0, #0]
teq r2, #0
bne 1b
dmb
b svc_exit
svc_000004_delay_mutex:
// r0 = struct Mutex* m
sub r0, #4
bl sched_mutex_yield
ldmfd sp!, {r0-r12,lr}
b schedule
svc_000005: // Release Mutex
ldr r0, [sp, #0] // struct Mutex* m
add r0, #4
mov r1, #0
dmb
str r1, [r0, #0]
dsb
sev
// TODO: Branch to scheduler to awake threads awaiting mutex
sub r0, #4
bl sched_mutex_resurrect
ldmfd sp!, {r0-r12,lr}
b schedule
b svc_exit
svc_exit:
ldmfd sp!, {r0-r12,pc}^
.section .data
svc_msg: .asciz "SVC Handler #"
|
