From 93bf62580a68533dc8252b9a2a055c02f34ecb67 Mon Sep 17 00:00:00 2001 From: Christian Cunningham Date: Thu, 24 Mar 2022 09:38:08 -0700 Subject: Modularized --- kernel/sys/schedule.S | 53 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 53 insertions(+) create mode 100644 kernel/sys/schedule.S (limited to 'kernel/sys/schedule.S') diff --git a/kernel/sys/schedule.S b/kernel/sys/schedule.S new file mode 100644 index 0000000..a47252c --- /dev/null +++ b/kernel/sys/schedule.S @@ -0,0 +1,53 @@ +.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 -- cgit v1.2.1