Help with this ASSUME issue

Index > Macroinstructions > Help with this ASSUME issue

Author

Thread

alorent

Joined: 05 Dec 2005
Posts: 221

alorent 23 Feb 2010, 19:57

Hello guys,

I'm having problems with the following code:

Code:

format PE GUI 4.0
entry start

include 'WIN32AX.INC'
include 'macro\masm.inc'
include 'macro\if.INC'


struct my_struct
   Member1   dd  ?
   Member2   dd  ?
ends

.data

.code 

start:

    assume ebp:my_struct
    mov eax, [ebp.Member1]       ; WORKS!!

    ; start the party....

    reg_base EQU ebp

    assume reg_base:my_struct
    mov eax, [reg_base.Member1]   ; <--- ERROR!!! "Undefined symbol reg_base.Member1"

How can I make the above work?

Thanks!!!

23 Feb 2010, 19:57

bitshifter

Joined: 04 Dec 2007
Posts: 796
Location: Massachusetts, USA

bitshifter 23 Feb 2010, 20:05

I never used assume, but i have used label

Code:

label reg_base at ebp

Maybe something like that would suit your needs?

23 Feb 2010, 20:05

alorent

Joined: 05 Dec 2005
Posts: 221

alorent 23 Feb 2010, 20:21

Thanks bitshifter! That works fine for the above example.

The problem is that I want to chage later the "reg_base" to another register:

Code:


label reg_base at ebp

label reg_base at edi    ; <--- FAILS!!! It says "symbol already defined"

Is there an alternative solution to support the above?

23 Feb 2010, 20:21

Borsuc

Joined: 29 Dec 2005
Posts: 2465
Location: Bucharest, Romania

Borsuc 23 Feb 2010, 20:46

Assume is a macro. "reg_base", if a symbolic constant (i.e 'equ' or 'define') will probably not get expanded, which is why it gives an error...

23 Feb 2010, 20:46

bitshifter

Joined: 04 Dec 2007
Posts: 796
Location: Massachusetts, USA

bitshifter 23 Feb 2010, 22:16

You could use dot operator (.) to give its own scope...

Code:

scope1:
label .x at ebp
scope2:
label .x at edi

...

mov edx,[scope1.x]
mov ecx,[scope2.x]

23 Feb 2010, 22:16

alorent

Joined: 05 Dec 2005
Posts: 221

alorent 24 Feb 2010, 06:01

Thanks bitshifter! I will try that!

24 Feb 2010, 06:01

< Last Thread | Next Thread >

Forum Rules:

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum