$-label oddities

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Marikallees

Joined: 21 Apr 2006
Posts: 4

Marikallees 25 Apr 2006, 14:54

Here's what I'm trying to do:

Code:

section '.data' data readable writable

string db  'Some string stuff'
length equ $-string

I expected the value of length to be the number of bytes in the string, but it seems the address given by $ and the address of the label are wildly different and the value of length is far too large. Can someone give me a hint as to what I'm doing wrong?

25 Apr 2006, 14:54

LocoDelAssembly
Your code has a bug

Joined: 06 May 2005
Posts: 4624
Location: Argentina

LocoDelAssembly 25 Apr 2006, 15:17

use "length = $-string". With equ you make "length" to be "$-string" instead of the value of $-string.

With EQU "mov eax, length" gets assembled as mov eax, $-string

With = "mov eax, length" gets assembled as mov eax, length

25 Apr 2006, 15:17

rugxulo

Joined: 09 Aug 2005
Posts: 2341
Location: Usono (aka, USA)

rugxulo 26 Apr 2006, 22:35

equ is for text while = is for numeric constants (or something like that). Here, read this, it should help explain it. Razz

26 Apr 2006, 22:35

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