aboutsummaryrefslogtreecommitdiff
path: root/src/sys/schedule.S
blob: a47252c51b696c4f52e2055a296b43b5f061c373 (plain)
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
.section ".text"
.globl schedule

.include "macros.inc"

// Assumption: Enter in SVC mode
schedule:
	preserve_ctx
	ldr r1, =irqlr
	ldr r0, [r1]
	cmp r0, #0
	beq 1f
	// Replace LR with IRQ's LR
	ldr r3, =scheduler
	ldr r2, [r3, #0] // struct Thread* rthread
	str r0, [r2, #0] // svc_lr -> void* pc
	// Clear IRQ's LR
	mov r0, #0
	str r0, [r1]
1:
	bl next_thread // Thread* next -> r0
	ldr r3, =scheduler
	str r0, [r3, #0] // next -> rthread
	restore_ctx
	subs pc, lr, #0

.globl cleanup
cleanup:
	bl c_cleanup
	// usrloop -> rthread
	ldr r3, =scheduler
	ldr r2, =usrloopthread
	str r2, [r3, #0]
	ldr sp, [r2, #4]
	ldmfd sp!,{lr}
	ldmfd sp!,{r0-r12}
	ldr lr, =kernel_usr_task_loop
	// svc sched
	svc #2
.globl kernel_usr_task_loop
kernel_usr_task_loop:
	wfe
	b kernel_usr_task_loop

.globl add_thread
add_thread:
	mrs r3, cpsr
	and r3, #0x1F
	cmp r3, #0x10
	beq 1f
	b svc_add_thread
1:	svc #3
	bx lr