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flat assembler > OS Construction > .. when i run it, my message in protected mode don't appear

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Fulgurance



Joined: 27 Nov 2017
Posts: 62
Hello, i have made code with little kernel and to test some fonctions.

But when i run it, my message in protected mode don't appear.

Code:
use16
org 0x7C00

xor ah,ah
xor dl,dl
int 0x13

mov ax,0x100
mov es,ax
xor bx,bx
mov ah,0x2
mov al,0x1
xor ch,ch
mov cl,0x2
xor dh,dh
xor dl,dl
int 0x13

jmp 0x1000

db 510-($-$$) dup 0x90
dw 0xAA55

org 0x1000

cli
lgdt [GDTProtectedMode.Descriptor]
mov eax,cr0
or al,0x1
mov cr0,eax
jmp 0x8:InitializeMain32

use32

InitializeMain32:
mov byte [0xB8000],'*'
mov byte [0xB8001],0x2
mov byte [0xB8002],' '
mov byte [0xB8003],0x0
mov byte [0xB8004],'I'
mov byte [0xB8005],0x7
mov byte [0xB8006],'n'
mov byte [0xB8007],0x7
mov byte [0xB8008],'i'
mov byte [0xB8009],0x7
mov byte [0xB800A],'t'
mov byte [0xB800B],0x7
mov byte [0xB800C],'i'
mov byte [0xB800D],0x7
mov byte [0xB800E],'a'
mov byte [0xB800F],0x7
mov byte [0xB8010],'l'
mov byte [0xB8011],0x7
mov byte [0xB8012],'i'
mov byte [0xB8013],0x7
mov byte [0xB8014],'z'
mov byte [0xB8015],0x7
mov byte [0xB8016],'e'
mov byte [0xB8017],0x7
mov byte [0xB8018],'M'
mov byte [0xB8019],0x7
mov byte [0xB801A],'a'
mov byte [0xB801B],0x7
mov byte [0xB801C],'i'
mov byte [0xB801D],0x7
mov byte [0xB801E],'n'
mov byte [0xB801F],0x7
mov byte [0xB8020],'3'
mov byte [0xB8021],0x7
mov byte [0xB8022],'2'
mov byte [0xB8023],0x7

Main32:
jmp short Main32

GDTProtectedMode:
.NullDescriptor:
dq 0x0
.CodeDescriptor:
dw 0xFFFF,0x0
db 0x0,11011001b,11110010b
db 0x0
.DataDescriptor:
dw 0xFFFF,0x0
db 0x0,11001001b,11110010b
db 0x0
.Descriptor:
dw 0x18
dd GDTProtectedMode

db 512-($-$$) dup 0x90
    
Post 16 May 2019, 22:25
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revolution
When all else fails, read the source


Joined: 24 Aug 2004
Posts: 16733
Location: In your JS exploiting you and your system
One thing I notice. You need to be sure about your CS value:
Code:
jmp 0:0x1000 ; the value of CS will vary between BIOSes so set it explicitly    
Post 17 May 2019, 15:46
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