ORG question/problem

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A.Cipher

Joined: 19 Jul 2008
Posts: 5

A.Cipher 25 Jul 2008, 21:05

Hello,

I was hoping that someone may help me with this.

I'm trying to organize my compilation at 0x200
in all my tests I find that fasm is compiling it at 0x100

test.asm

Code:

org 200h

mov ax,99h

test dissembled

Code:

; title Disassembly of file: TEST.BIN - produced by DASM.EXE v1.02

L0099           equ     0x0099

org             0x0100

L0100:          mov     ax,L0099

Thanks,
A.Ci

25 Jul 2008, 21:05

windwakr

Joined: 30 Jun 2004
Posts: 827

windwakr 25 Jul 2008, 21:39

org does nothing when you're directly loading a number into a register
It affects jumps and moving locations into registers and stuff like that.

Like:

Code:

org 200h
mov ax,loc1

loc1:

will disassemble to

Code:

mov ax,203h

25 Jul 2008, 21:39

DOS386

Joined: 08 Dec 2006
Posts: 1904

DOS386 26 Jul 2008, 06:34

> I'm trying to organize my compilation at 0x200
> in all my tests I find that fasm is compiling it at 0x100

Problem specific to DOS COM ... DOS loads COM's always at $0100. Idea

26 Jul 2008, 06:34

baldr

Joined: 19 Mar 2008
Posts: 1651

baldr 26 Jul 2008, 10:18

Do you need to position code at 0x200 in binfile, or just to assemble it as if it starts at 0x200?
org directive does no more than change base for the following code. No padding, no alignment Wink

26 Jul 2008, 10:18

A.Cipher

Joined: 19 Jul 2008
Posts: 5

A.Cipher 26 Jul 2008, 14:31

Thanks guys,

the easiest way to explain is I was just trying to position/pad it to start at 0x200 in bin file.

I finally did just add in

Code:

times 100- ($-INITIAL)  db 0

A.Ci

26 Jul 2008, 14:31

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