/
scheduler.s
87 lines (73 loc) · 2.88 KB
/
scheduler.s
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
;
; This is free and unencumbered software released into the public domain.
;
; Anyone is free to copy, modify, publish, use, compile, sell, or
; distribute this software, either in source code form or as a compiled
; binary, for any purpose, commercial or non-commercial, and by any
; means.
;
; In jurisdictions that recognize copyright laws, the author or authors
; of this software dedicate any and all copyright interest in the
; software to the public domain. We make this dedication for the benefit
; of the public at large and to the detriment of our heirs and
; successors. We intend this dedication to be an overt act of
; relinquishment in perpetuity of all present and future rights to this
; software under copyright law.
;
; THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
; EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
; MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
; IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR
; OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
; ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
; OTHER DEALINGS IN THE SOFTWARE.
;
; For more information, please refer to <http://unlicense.org>
;
section .text
align 4
global run_kernel_task
global run_user_task
run_kernel_task:
cli
mov eax, [esp+4] ; load task_register_t pointer to eax
mov ebx, [eax+4]
mov ecx, [eax+8]
mov edx, [eax+12]
mov ebp, [eax+16]
mov esi, [eax+20]
mov edi, [eax+24]
; restore the stack pointer
mov esp, [eax+32]
; push information for iret onto the stack
push DWORD [eax+36] ; push EFLAGS
push DWORD [eax+40] ; push the segment selector
push DWORD [eax+44] ; push EIP
mov eax, [eax] ; restore eax
iret ; iret to return to the process
run_user_task:
cli ; disable external interrupts
mov eax, [esp+4] ; load address of registers_t into eax
; restore all the registers except eax
mov ebx, [eax+4]
mov ecx, [eax+8]
mov edx, [eax+12]
mov ebp, [eax+16]
mov esi, [eax+20]
mov edi, [eax+24]
; push information for iret onto the stack
push DWORD [eax+28] ; push the SS onto the stack
push DWORD [eax+32] ; push the ESP of the user stack
push DWORD [eax+36] ; push EFLAGS
push DWORD [eax+40] ; push the segment selector
push DWORD [eax+44] ; push EIP
; move index for the data segment into data registers
push ecx
mov cx, [eax+28]
mov ds, cx
mov gs, cx
mov es, cx
mov fs, cx
pop ecx
mov eax, [eax] ; restore eax
iret ; iret into the given mode