- org 0x0
+ org 0xA8000
[bits 16]
entry:
-; mov al, 0x01 ; Say where we are.
-; out 0x80, al
mov ax, 0xA800
mov ds, ax ; Take us out of flat unreal mode, and
mov es, ax ; put us in true real mode.
mov fs, ax
mov gs, ax
mov ss, ax
- jmp 0xA800:entry2 ; Long jump to a correct cs.
+ jmp 0xA800:(entry2-0xA8000) ; Long jump to a correct cs.
entry2:
-; mov al, 0x02
-; out 0x80, al
- lgdt [gdtr] ; Set up a new GDT.
+ lgdt [(gdtr-0xA8000)] ; Set up a new GDT.
mov eax, 0x1
mov cr0, eax ; ... and enter pmode!
- mov al, 0x03 ; Say we got here.
- out 0x80, al
- jmp long 0x10:(continue+0xA8000) ; Now longjmp into the new code.
+ jmp long 0x10:continue ; Now longjmp into the new code.
[bits 32]
continue:
-; mov al, 0x04 ; Now we're in protected mode.
-; out 0x80, al
-
mov ax, 0x08 ; Set up segment selectors.
mov ds, ax
mov es, ax
mov fs, ax
mov gs, ax
mov ss, ax
- mov esp, 0x1fffffff
+ mov esp, [dataptr]
-; mov al, 0x05
+; mov al, [cstat]
+; add al, 1
; out 0x80, al
-
- mov al, [(cstat + 0xA8000)]
- add al, 1
- out 0x80, al
- mov [(cstat + 0xA8000)], al
+; mov [cstat], al
- mov eax, 0x11223344
- mov dword [(status + 0xA8000)], eax
-
mov dx, 0xCF8 ; save off the old config value
in dword eax, dx
mov [esp-4], eax
shl eax, 1
add eax, 0xB8000 ; yay
mov byte [eax+0], '1'
- mov byte [eax+1], 0xA0
+ mov byte [eax+1], 0x1F
mov byte [eax+2], '5'
- mov byte [eax+3], 0xA0
+ mov byte [eax+3], 0x1F
mov byte [eax+4], '-'
- mov byte [eax+5], 0xA0
+ mov byte [eax+5], 0x1F
mov byte [eax+6], '4'
- mov byte [eax+7], 0xA0
+ mov byte [eax+7], 0x1F
mov byte [eax+8], '1'
- mov byte [eax+9], 0xA0
+ mov byte [eax+9], 0x1F
mov byte [eax+10], '2'
- mov byte [eax+11], 0xA0
+ mov byte [eax+11], 0x1F
- mov dx, 0x3D4
+ mov dx, 0x3D4 ; restore the old stuff
mov al, [esp-6]
out dx, al
-
mov dx, 0xCFC ; restore smramc
mov al, [esp-5]
out dx, al
- mov dx, 0xCF8 ; restore the old config value
+ mov dx, 0xCF8 ; restore the old PCI config value
mov eax, [esp-4]
out dx, eax
+ mov al, [needclear]
+ cmp al, 0
+ jz noclear
+ mov al, 0 ; clear BSS
+ mov edi, [dataptr+4]
+ mov ecx, [dataptr+8]
+ rep stosb
+ mov [needclear], al
+
+noclear:
+ mov eax, [dataptr+12] ; jump into C
+ call eax
+
mov al, 0x40 ; ack the periodic IRQ
mov dx, 0x834
out dx, al
- mov dx, 0x830
+ mov dx, 0x830 ; now ack the SMI itself
in al, dx
- or al, 0x02 ; now ack the SMI itself
+ or al, 0x02
and al, 0xBF
out dx, al
or al, 0x40
rsm ; and leave SMM
+needclear:
+ db 0x01
+
align 0x4
gdtr:
db 0x27, 0x00
- dd (gdt + 0xA8000)
+ dd gdt
align 0x4
gdt:
db 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
db 0xFF, 0xFF, 0x00, 0x00, 0x00, 0x9B, 0xCF, 0x00 ; code segment
db 0xFF, 0xFF, 0x00, 0x80, 0x0A, 0x9B, 0xCF, 0x00 ; code segment for trampoline
-TIMES 512-($-$$) DB 0
-status:
- dd 0xAA55AA55
cstat:
db 0x00
+
+TIMES 512-($-$$) DB 0
+dataptr:
+ ; 4 bytes of stack top
+ ; 4 bytes of BSS start
+ ; 4 bytes of BSS length
+ ; 4 bytes of C entry point
\ No newline at end of file