Has struc changed?

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chorus

Joined: 16 Mar 2004
Posts: 23

chorus 22 Dec 2005, 01:02

It's been awhile since I've done any coding with FASM. Has the usage of struc changed wrt register pointers? (since, oh, version 1.5)

I used to be able to do stuff like

Code:

mov [ebx+SOMESTRUCTURE.somemember],eax

but now I can't... I get "undefined symbol" when I assemble. The only way I can get around this is to do:

Code:

virtual at 0
  SOMESTRUCTURE SOMESTRUCTURE
end virtual

Didn't have to do that before...

--Chorus

22 Dec 2005, 01:02

revolution
When all else fails, read the source

Joined: 24 Aug 2004
Posts: 20446
Location: In your JS exploiting you and your system

revolution 22 Dec 2005, 01:55

It depends on how you instantiated your structure after defining it. If you have your own "struct" macro then nothing has changed, but if you use the "struct" macro from the package then a lot has changed because of handling if the "." character. Perhaps you can show how you have defined your structure then I can help to get it working the way you want.

22 Dec 2005, 01:55

chorus

Joined: 16 Mar 2004
Posts: 23

chorus 23 Dec 2005, 15:39

I'm not using any macro. I'm using the "struc" that is built into fasm (or at least I believe it's built in... it's in the documentation).

Perhaps before I was using the macro without knowing it... probably it's in the standard includes. Thing is I was using Windows before so those includes are there and now I'm using linux and they aren't (stuff like invoke, etc)

So I should assume "struc" works the way I described and "struct" works the way I want, but it's a macro. Does that sound about right?

--Chorus

23 Dec 2005, 15:39

chorus

Joined: 16 Mar 2004
Posts: 23

chorus 23 Dec 2005, 15:47

This is how I've defined the structure

Code:

struc BITSTREAM
{
        .lpbitstream dq ?
        .cbBuffer dq ?
        .nPosition dq ?
}

To get it to work I need to have

Code:

virtual at 0
  BITSTREAM BITSTREAM
end virtual

--Chorus

23 Dec 2005, 15:47

revolution
When all else fails, read the source

Joined: 24 Aug 2004
Posts: 20446
Location: In your JS exploiting you and your system

revolution 24 Dec 2005, 02:44

You have two main options that I can see. If you are programming for WIN32 you can use the package macro "STRUCT" like this:

Code:

include 'win32a.inc'

struct BITSTREAM 
        lpbitstream dq ? 
        cbBuffer dq ? 
        nPosition dq ? 
ends

Or if you want to use your own "STRUCT" you can do something like this:

Code:

macro struct name
{       virtual at 0
        name name
        sizeof.#name = $
        name#.size = $
        end virtual
}

struc BITSTREAM 
{ 
        .lpbitstream dq ? 
        .cbBuffer dq ? 
        .nPosition dq ? 
}
struct BITSTREAM

24 Dec 2005, 02:44

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