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Index > Macroinstructions > "Assuming" parameters

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alorent



Joined: 05 Dec 2005
Posts: 201
alorent
Hello!

I was wondering what's wrong with this assume in the "proc" parameter:

Code:
format PE GUI 4.0
entry start

include 'win32ax.inc'
include 'macro\if.inc'
include 'macro\masm.inc'

struct my_struct
   Member1   dd  ?
   Member2   dd  ?
ends


list_member dd 11111111h, 22222222h


.code

start:

    stdcall  MyProc, list_member    



MyProc proc pList

    assume pList:my_struct

    push   [pList.Member1]     ; FASM error here: "undefined symbol pList.Member1"

MyProc endp    


I guess the problem is that "pList" is taken as [ebp + XXX] and the assume causes error there.

Or maybe is there an alternative macro "assume_ptr" that can deal with that type of "assuming"?

Thanks in advance!
Post 17 Nov 2010, 21:25
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baldr



Joined: 19 Mar 2008
Posts: 1651
baldr
alorent,

assume macro from MACRO\MASM.INC is limited to assume reg:struct syntax.

Let's see, pList is a pointer to structure? x86 doesn't support double indirection, you have to put pointer in register beforehand (then assume becomes useful).
Post 17 Nov 2010, 23:03
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alorent



Joined: 05 Dec 2005
Posts: 201
alorent
Thanks baldr.

Well, it seems that the following is accepted (at least with latest FASM):

Code:
assume list_member:my_struct
mov    eax, [list_member.Member1]    


Thanks!
Post 18 Nov 2010, 12:46
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baldr



Joined: 19 Mar 2008
Posts: 1651
baldr
alorent,

list_member should be address of my_struct then, not address of pointer to it. You may think of assume as type cast.

That's my favorite part: there are ways thing is supposed to be used, and much more ways thing can be used (some of them are productive too). Wink
Post 18 Nov 2010, 17:51
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alorent



Joined: 05 Dec 2005
Posts: 201
alorent
Thanks for clarifying that baldr! Wink
Post 19 Nov 2010, 05:49
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