]>
Commit | Line | Data |
---|---|---|
1 | org 0xA8000 | |
2 | [bits 16] | |
3 | entry: | |
4 | mov ax, 0xA800 | |
5 | mov ds, ax ; Take us out of flat unreal mode, and | |
6 | mov es, ax ; put us in true real mode. | |
7 | mov fs, ax | |
8 | mov gs, ax | |
9 | mov ss, ax | |
10 | jmp 0xA800:(entry2-0xA8000) ; Long jump to a correct cs. | |
11 | entry2: | |
12 | lgdt [(gdtr-0xA8000)] ; Set up a new GDT. | |
13 | mov eax, 0x1 | |
14 | mov cr0, eax ; ... and enter pmode! | |
15 | jmp long 0x10:continue ; Now longjmp into the new code. | |
16 | [bits 32] | |
17 | continue: | |
18 | mov ax, 0x08 ; Set up segment selectors. | |
19 | mov ds, ax | |
20 | mov es, ax | |
21 | mov fs, ax | |
22 | mov gs, ax | |
23 | mov ss, ax | |
24 | mov esp, [dataptr] | |
25 | ||
26 | ; mov al, [cstat] | |
27 | ; add al, 1 | |
28 | ; out 0x80, al | |
29 | ; mov [cstat], al | |
30 | ||
31 | mov dx, 0xCF8 ; save off the old config value | |
32 | in dword eax, dx | |
33 | mov [esp-4], eax | |
34 | ||
35 | mov eax, 0x80000070 ; load in smramc | |
36 | out dx, eax | |
37 | mov dx, 0xCFC | |
38 | in byte al, dx | |
39 | mov [esp-5], al | |
40 | and al, 0xF3 ; Allow graphics access | |
41 | or al, 0x08 | |
42 | out dx, al | |
43 | ||
44 | xor eax, eax | |
45 | mov dx, 0x3D4 | |
46 | in byte al, dx | |
47 | mov [esp-6], al ; save off the old VGA command | |
48 | mov al, 0xC | |
49 | out dx, al | |
50 | inc dx | |
51 | in al, dx | |
52 | mov ah, al | |
53 | dec dx | |
54 | mov al, 0xD | |
55 | out dx, al | |
56 | inc dx | |
57 | in al, dx | |
58 | shl eax, 1 | |
59 | add eax, 0xB8000 ; yay | |
60 | mov byte [eax+0], '1' | |
61 | mov byte [eax+1], 0x1F | |
62 | mov byte [eax+2], '5' | |
63 | mov byte [eax+3], 0x1F | |
64 | mov byte [eax+4], '-' | |
65 | mov byte [eax+5], 0x1F | |
66 | mov byte [eax+6], '4' | |
67 | mov byte [eax+7], 0x1F | |
68 | mov byte [eax+8], '1' | |
69 | mov byte [eax+9], 0x1F | |
70 | mov byte [eax+10], '2' | |
71 | mov byte [eax+11], 0x1F | |
72 | ||
73 | mov dx, 0x3D4 ; restore the old stuff | |
74 | mov al, [esp-6] | |
75 | out dx, al | |
76 | ||
77 | mov al, 0 | |
78 | mov edi, [dataptr+4] ; clear BSS | |
79 | mov ecx, [dataptr+8] | |
80 | rep stosb | |
81 | ||
82 | mov dx, 0xCFC ; restore smramc | |
83 | mov al, [esp-5] | |
84 | out dx, al | |
85 | ||
86 | mov eax, [dataptr+12] | |
87 | call eax | |
88 | ||
89 | mov dx, 0xCF8 ; restore the old config value | |
90 | mov eax, [esp-4] | |
91 | out dx, eax | |
92 | ||
93 | mov al, 0x40 ; ack the periodic IRQ | |
94 | mov dx, 0x834 | |
95 | out dx, al | |
96 | ||
97 | mov dx, 0x830 | |
98 | in al, dx | |
99 | or al, 0x02 ; now ack the SMI itself | |
100 | and al, 0xBF | |
101 | out dx, al | |
102 | or al, 0x40 | |
103 | out dx, al | |
104 | ||
105 | rsm ; and leave SMM | |
106 | ||
107 | align 0x4 | |
108 | gdtr: | |
109 | db 0x27, 0x00 | |
110 | dd gdt | |
111 | align 0x4 | |
112 | gdt: | |
113 | db 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 | |
114 | db 0xFF, 0xFF, 0x00, 0x00, 0x00, 0x93, 0xCF, 0x00 ; data segment | |
115 | db 0xFF, 0xFF, 0x00, 0x00, 0x00, 0x9B, 0xCF, 0x00 ; code segment | |
116 | db 0xFF, 0xFF, 0x00, 0x80, 0x0A, 0x9B, 0xCF, 0x00 ; code segment for trampoline | |
117 | ||
118 | cstat: | |
119 | db 0x00 | |
120 | ||
121 | TIMES 512-($-$$) DB 0 | |
122 | dataptr: | |
123 | ; 4 bytes of stack top | |
124 | ; 4 bytes of BSS start | |
125 | ; 4 bytes of BSS length | |
126 | ; 4 bytes of C entry point |