OSdev
Posted: Thu Dec 09, 2004 7:25 am
I want create my OS. I do a bootloader byt i dont known how enter protected mode?
Can help me?
Can help me?
But it doesn't work[BITS 16]
[ORG 0x7C00]
jmp 0x8000
times 510-($-$$) db 0
dw 0xAA55
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Re:OSdev
Posted: Thu Dec 09, 2004 7:32 am
I jump to 16 bit kernel at 0x8000
Re:OSdev
Posted: Thu Dec 09, 2004 7:36 am
you're assuming that CS will be 0 instead of enforcing it. If your kernel is indeed loaded at 0x8000, just do
and it'll be fine.
As for protected mode setup, i suggest you get a look at BonaFide and OSRC tutorials, as suggested in the FAQ and .:QuickLinkz:.
Code: Select all
jmp 0000:0x8000
As for protected mode setup, i suggest you get a look at BonaFide and OSRC tutorials, as suggested in the FAQ and .:QuickLinkz:.
Re:OSdev
Posted: Thu Dec 09, 2004 7:38 am
Please tell me your nick has some SF background and wasn't meant as offense. 
Re:OSdev
Posted: Thu Dec 09, 2004 7:43 am
MegaTokyo FAQ doesn't work. And My bootloader work's.
Greets from Lituania
Greets from Lituania
Re:OSdev
Posted: Thu Dec 09, 2004 7:49 am
Can you be more specific ? (e.g. post the error code/msg you get in the "working on the FAQ" thread ...)Solar_worm wrote: MegaTokyo FAQ doesn't work.
Re:OSdev
Posted: Thu Dec 09, 2004 7:50 am
How I can with debug option write to 2nd sector
?debug stage2
-w 100 0 0 2
-q
Re:OSdev
Posted: Thu Dec 09, 2004 8:27 am
haven't toyed with msdebug for ages. i guess it should have some help somewhere (try out "help debug" or "h" in debug)
people around here use tools like rawrite or winimage for floppy management ...
people around here use tools like rawrite or winimage for floppy management ...
Re:OSdev
Posted: Thu Dec 09, 2004 10:01 am
This is the smalist code for geting into pmode.
Assemble with fasm.
PS: The space in the text, must be the same as above.
\\\\||////
(@@)
ASHLEY4.
Batteries not included, Some assembly required.
Code: Select all
;************************************
; \\|//
; (@ @)
; ASHLEY4.
; Put test.bin on boot sector
; with rawrite.
; Assemble with fasm
; c:\fasm test.asm test.bin
;************************************
org 0x7C00
use16
;****************************
; Realmode startup code.
;****************************
start:
xor ax,ax
mov ds,ax
mov es,ax
mov ss,ax
mov sp,0x7C00
;*****************************
; Setting up, to enter pmode.
;*****************************
cli
lgdt [gdtr]
mov eax, cr0
or al,0x1
mov cr0,eax
jmp 0x10: protected
;*****************************
; Pmode. ;-)
;*****************************
use32
protected:
mov ax,0x8
mov ds,ax
mov es,ax
mov ss,ax
mov esp,0x7C00
;*****************************
; Turn floppy off (if space).
;*****************************
mov dx,3F2h
mov al,0
out dx,al
lea esi,[msg0]
mov edi,0xB8000 + (80 * 3 + 4) * 2
mov ecx,28
cld
rep movsb
jmp $
;*************************************
; GDT.
;*************************************
gdt: dw 0x0000, 0x0000, 0x0000, 0x0000
sys_data: dw 0xFFFF, 0x0000, 0x9200, 0x00CF
sys_code: dw 0xFFFF, 0x0000, 0x9800, 0x00CF
gdt_end:
gdtr: dw gdt_end - gdt - 1
dd gdt
;*************************************
; Data.
;*************************************
msg0 db " H E L L O W O R L D ! "
;*************************************
; Make program 510 byte's + 0xaa55
;*************************************
times 510- ($-start) db 0
dw 0xaa55 PS: The space in the text, must be the same as above.
\\\\||////
(@@)
ASHLEY4.
Batteries not included, Some assembly required.
Re:OSdev
Posted: Fri Dec 10, 2004 5:51 am
Thx,
Why i cant assembly it with nasm?
Why i cant assembly it with nasm?
Re:OSdev
Posted: Fri Dec 10, 2004 6:50 am
change "use16" to "[bits 16]" and it should work in nasm aswell.
Re:OSdev
Posted: Fri Dec 10, 2004 8:29 am
And I must change
to:
times 510- ($-start) db 0
dw 0xaa55
to:
???times 510- ($-$$) db 0
dw 0xAA55
Re:OSdev
Posted: Fri Dec 10, 2004 3:51 pm
correct.Solar_worm wrote: And I must changetimes 510- ($-start) db 0
dw 0xaa55
to:???times 510- ($-$$) db 0
dw 0xAA55
Not neccesarily needed, you can use "use16" and still it should work.change "use16" to "[bits 16]" and it should work in nasm aswell.
HTH,
DennisCGc.
PS:
You can also use:Code: Select all
lea esi,[msg0]
Code: Select all
mov esi,msg0