diff options
Diffstat (limited to 'kernel/l0/context_switch.s')
| -rw-r--r-- | kernel/l0/context_switch.s | 46 |
1 files changed, 46 insertions, 0 deletions
diff --git a/kernel/l0/context_switch.s b/kernel/l0/context_switch.s new file mode 100644 index 0000000..7351997 --- /dev/null +++ b/kernel/l0/context_switch.s @@ -0,0 +1,46 @@ +[EXTERN kernel_stack_top] +[EXTERN run_scheduler] + +[GLOBAL save_context_and_enter_scheduler] +; void save_context_and_enter_scheduler(struct saved_context *ctx); +save_context_and_enter_scheduler: + pushf + cli + pusha ; Pushes edi,esi,ebp,esp,ebx,edx,ecx,eax + + mov eax, cr3 + push eax + + mov ax, ds ; Lower 16-bits of eax = ds. + push eax ; save the data segment descriptor + + mov eax, [esp+48] ; get address of saved_context structure + mov [eax], esp ; save esp + mov dword [eax+4], resume_saved_context ; save eip + + mov esp, kernel_stack_top + jmp run_scheduler + +resume_saved_context: + pop eax + mov ds, ax + mov es, ax + mov fs, ax + mov gs, ax + + pop eax + mov cr3, eax + + popa + popf + ret + + +[GLOBAL resume_context] +resume_context: + mov eax, [esp+4] ; get address of saved context + mov esp, [eax] ; resume esp + mov ecx, [eax+4] ; jump to specified eip + jmp ecx + +; vim: set ts=4 sw=4 tw=0 noet : |