Local Variable Troubles...

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GuyonAsm

Joined: 27 Sep 2003
Posts: 45

GuyonAsm 23 Dec 2003, 04:13

Okay Im having serious trouble here with local variables.

Code:

proc ListProcesses
        .SnapShot dd 0
        .cProcess PROCESSENTRY32
        enter
        invoke CreateToolhelp32Snapshot, TH32CS_SNAPPROCESS, 0
        mov [.SnapShot],eax
        ;setup code for processentry crap here, it works.
        invoke Process32First,[.SnapShot], .cProcess
                 ;code here
    _bListProc:
                   ;code here
          jmp     _bListProc
    _eListProc:
                   ;code here
  return

Now my problem is i always get "invalid value".... Im so lost. when i declare this stuff in data section... no problems what so ever, everything works flawlessly, but when i invoke a procedure using local variables, the locals always turn up errors. I'd like to know if there is a way to fix this, as I really want to implement local variables into this project im working on so that i can clean up the code alot.

one way i was thinking was if i...

Code:

push .cProcess
push .SnapShot
call [Process32First]
...

but its late right now, im real frustrated and i must sleep. I hope someone can help me here with this.

_________________
I shall not evade what is predestined
because every battle, is another lesson
- GuyonAsm.

A Believer of The System.

23 Dec 2003, 04:13

comrade

Joined: 16 Jun 2003
Posts: 1140
Location: Russian Federation

comrade 23 Dec 2003, 04:45

Try:

Code:

.cProcess rb sizeof.PROCESSENTRY32

And should you not lea .cProcess when passing it to Process32First?

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comrade (comrade64@live.com; http://comrade.ownz.com/)

23 Dec 2003, 04:45

comrade

Joined: 16 Jun 2003
Posts: 1140
Location: Russian Federation

comrade 23 Dec 2003, 04:48

I found problem, this happen because you define PROCESSENTRY32 after code, and before data. That is why it work in data section and not in code.

Strange, but I thought FASM would do additional passes to resolve this structure definition... But this is parser (?) stage and passes are done in assembly stage only?

_________________
comrade (comrade64@live.com; http://comrade.ownz.com/)

23 Dec 2003, 04:48

JohnFound

Joined: 16 Jun 2003
Posts: 3499
Location: Bulgaria

JohnFound 23 Dec 2003, 06:51

Code:

proc ListProcesses
  .SnapShot dd 0
  .cProcess PROCESSENTRY32
        enter
        invoke CreateToolhelp32Snapshot, TH32CS_SNAPPROCESS, 0
        mov [.SnapShot],eax
        ;setup code for processentry crap here, it works.
        lea     eax, [.cProcess]
        invoke Process32First,[.SnapShot], .cProcess
                     ;code here
    .bListProc:
                   ;code here
          jmp     .bListProc
    .eListProc:
                   ;code here
  return

Hi. Try above. It should work.
Note that you can't get the address of local variable in assembly time, because this address is simply unknown (local variables are in the stack).
Other assemblers work the same way, but simply hides this from you.

Regards.

23 Dec 2003, 06:51

Tommy

Joined: 17 Jun 2003
Posts: 489
Location: Norway

Tommy 23 Dec 2003, 07:54

John, ain't

Code:

lea     eax, [.cProcess] 
invoke Process32First,[.SnapShot], .cProcess

going to be:

Code:

lea     eax, [.cProcess] 
invoke Process32First,[.SnapShot], eax

?

Tommy

23 Dec 2003, 07:54

JohnFound

Joined: 16 Jun 2003
Posts: 3499
Location: Bulgaria

JohnFound 23 Dec 2003, 08:18

Hi, Tommy.
Of course you are right. I am still sleeping this morning. Very Happy

Regards.

23 Dec 2003, 08:18

Tommy

Joined: 17 Jun 2003
Posts: 489
Location: Norway

Tommy 23 Dec 2003, 08:38

Hehe...

23 Dec 2003, 08:38

Kevin_Zheng

Joined: 04 Jul 2003
Posts: 125
Location: China

Kevin_Zheng 23 Dec 2003, 13:33

One Error: The local variable can't initalize on complier period.
So the define is invalid:

Code:

.SnapShot dd 0

It should be the belowing :

Code:

.SnapShot dd  ?

Code:

.SnapShot rd 1

23 Dec 2003, 13:33

JohnFound

Joined: 16 Jun 2003
Posts: 3499
Location: Bulgaria

JohnFound 23 Dec 2003, 13:40

Kevin_Zheng wrote:

One Error: The local variable can't initalize on complier period.

Of course local variables can not be initialized on compile time, but actually this is not an error. The compilation will pass normally, only you should know that this variable will be initialized with random (even on every call of procedure) value.

Regards.

23 Dec 2003, 13:40

GuyonAsm

Joined: 27 Sep 2003
Posts: 45

GuyonAsm 23 Dec 2003, 14:40

Thanks guys, I'll try this out when I get home. If it works I'll be able to make the code for a project im working on( and even future windows oriented projects) that much more efficient, when it comes to procedures. Once again thanks everyone for the replys.

_________________
I shall not evade what is predestined
because every battle, is another lesson
- GuyonAsm.

A Believer of The System.

23 Dec 2003, 14:40

GuyonAsm

Joined: 27 Sep 2003
Posts: 45

GuyonAsm 23 Dec 2003, 20:10

comrade wrote:

Try:
Code:
.cProcess rb sizeof.PROCESSENTRY32    
And should you not lea .cProcess when passing it to Process32First?

Hmm, so when i do this, could i do as they do in nasm and go

Code:

mov [.cProcess+PROCESSENTRY32.dwSize],sizeof.PROCESSENTRY32

would that work when filling that or what?

Thanks everyone for the advice, i'll answer back here with my results.

EDIT EDIT EDIT EDIT NEW NEW NEW EDIT EDIT EDIT EDIT
New problem arising now.

Code:

proc ListProcesses, sck
        .SnapShot rd 1
        .Process32 rb sizeof.PROCESSENTRY32
        .Process rb 256
        .PID rb 12
        .Threads rb 12
 enter
        invoke CreateToolhelp32Snapshot,2,0
        mov     [.SnapShot],eax
        mov  dword [.Process32+PROCESSENTRY32.dwSize],sizeof.PROCESSENTRY32
        lea   eax,[.Process32]
        invoke      Process32First,[.SnapShot],eax
    _bListProc:
       cmp     eax,1
       jne     _eListProc
        lea       eax,[.Process] ;the error is occuring here.
        invoke   lstrcpyn,eax,szCmd3,2
        ;code here
         jmp     _bListProc
    _eListProc:
   ;code here
  return

on the line lea eax,[.Process]

i get "undefined symbol"... yet the freaking symbol is declared in the local right there.

Now as i test renaming the variable to something else its the exact same thing, so im coming to the conclusion that maybe these lea instructions aren't gonna work with the proc? I hope im not forced to make all these global variables, thereby wasting memory in the prog....

_________________
I shall not evade what is predestined
because every battle, is another lesson
- GuyonAsm.

A Believer of The System.

23 Dec 2003, 20:10

JohnFound

Joined: 16 Jun 2003
Posts: 3499
Location: Bulgaria

JohnFound 24 Dec 2003, 16:07

It is not because of local variables.
You simply forget to define some of the structures. You MUST define them in your source if they are not defined in standard include files.

Regards.

24 Dec 2003, 16:07

GuyonAsm

Joined: 27 Sep 2003
Posts: 45

GuyonAsm 24 Dec 2003, 16:24

i've used the processentry32 structure before, as ive included it myself inside the kernel equates. I know that the structure is there because when using *cough* global variables, it worked perfectly, but here we go again with this local variable crap. =(

nm now though, I think im just gonna use all gloval variables for this. the next thing I work on (which will be the flat assembler instant messenger(FAIM)) I will try this again.... Crying or Very sad

_________________
I shall not evade what is predestined
because every battle, is another lesson
- GuyonAsm.

A Believer of The System.

Last edited by GuyonAsm on 24 Dec 2003, 17:43; edited 1 time in total

24 Dec 2003, 16:24

silkodyssey

Joined: 02 Oct 2003
Posts: 198
Location: St.Vincent & the Grenadines

silkodyssey 24 Dec 2003, 17:05

GuyonAsm,

Will the instant messenger use existing protocols like msn's or yahoo's?

_________________
silkodyssey

24 Dec 2003, 17:05

GuyonAsm

Joined: 27 Sep 2003
Posts: 45

GuyonAsm 24 Dec 2003, 17:16

Its something VeSCeRa and I are gonna put together, perhaps with the help of others. So far it'll be Icq and Aim. Perhaps if we get documentation on other protocols, we could include those later on also.

_________________
I shall not evade what is predestined
because every battle, is another lesson
- GuyonAsm.

A Believer of The System.

24 Dec 2003, 17:16

vid
Verbosity in development

Joined: 05 Sep 2003
Posts: 7105
Location: Slovakia

vid 24 Dec 2003, 21:33

GuyonAsm: no harm, but i think you shouldnt be using macros unless you know how they are working. I advice you to study 'proc', 'enter', 'return', 'invoke' and mainly 'pushd' which will tell you about 'addr' pseudo operator which can be used instead of lea.

24 Dec 2003, 21:33

Dunduk

Joined: 08 Sep 2003
Posts: 38
Location: Russia

Dunduk 25 Dec 2003, 04:53

GuyonAsm wrote:

on the line lea eax,[.Process]

i get "undefined symbol"...

Try

Code:

lea eax,[ListProcesses.Process]

It should work. ".Process" - is local label IMHO and after " _bListProc" label fasm didn't see it (oh, my english...). I think so.

25 Dec 2003, 04:53

GuyonAsm

Joined: 27 Sep 2003
Posts: 45

GuyonAsm 25 Dec 2003, 06:01

Well gosh darn, I think your right. And yes sir it works. Thanks alot. Now i can continue on with my project. To discontinue any temptation of abandoning fasm to use another assembler (such as masm or etc.) I've just deleted all the assemblers i had on my comp etc. fasm. I will depend on fasm now =).

Ahh im so happy, this is a christmas present in itself. Thank you sooo much. Very Happy

_________________
I shall not evade what is predestined
because every battle, is another lesson
- GuyonAsm.

A Believer of The System.

25 Dec 2003, 06:01

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