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.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
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