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Index > Windows > newb problem:what's wrong with this code?

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hitertan



Joined: 12 Mar 2004
Posts: 15
Location: China
hitertan
I'm a newbie in assemble language.Today when i programming i am held by one curious mistake.I have written some simple codes to stand out the mistake:
Code:
include '%fasminc%/win32ax.inc'
 
 .code
    start:
       call testProc
       invoke ExitProcess,0
proc testProc
       .testLocal dd ?
     enter
       push eax
testGoto1:      
    mov eax,3
   mov [.testLocal],eax
        pop eax
     return
      
    .end start
    

the fasm compile output the compile error below:
Quote:

mov [.testLocal],eax
error: undefined symbol

But when I comment the label testGoto1:,the codes can be compiled ok.
the correct codes is below
Code:
 include '%fasminc%/win32ax.inc'
 
 .code
    start:
            call testProc
       invoke ExitProcess,0
proc testProc
       .testLocal dd ?
     enter
       push eax
;testGoto1:     
    mov eax,3
   mov [.testLocal],eax
        pop eax
     return
      
    .end start
    

What's the wrong i'am making?

_________________
i like assembly language and i study it in my pleasure time
tanshunquan@hotmail.com
Post 17 Mar 2004, 13:26
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aaro



Joined: 21 Jun 2003
Posts: 107
Location: hel.fi
aaro
proc defines global testProc label and dot before testLocal makes it child label of testProc, so it comes testProc.testLocal. Now when you define global label(no dot before it) testGoto1 it changes prefix to testGoto1 so after that when you try to access .testLocal it's same as writing testGoto1.testLocal.

Solution: use local labels(labels starting with dot) inside proc's. If you need global label inside of proc you need to use label beginning with 2 dots, it's global but doesn't change current prefix for the local labels.

You should read more about labels from fasm.txt
Post 17 Mar 2004, 13:46
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Iehbr



Joined: 17 Mar 2004
Posts: 1
Iehbr
hitertan wrote:
I'm a newbie in assemble language.Today when i programming i am held by one curious mistake.I have written some simple codes to stand out the mistake:
Code:
include '%fasminc%/win32ax.inc'
 
 .code
    start:
        call testProc
       invoke ExitProcess,0
proc testProc
       .testLocal dd ?
     enter
       push eax
testGoto1:      
    mov eax,3
   mov [.testLocal],eax
        pop eax
     return
      
    .end start
    

the fasm compile output the compile error below:
Quote:

mov [.testLocal],eax
error: undefined symbol

But when I comment the label testGoto1:,the codes can be compiled ok.
the correct codes is below
What's the wrong i'am making?


Use 'stdcall testProc'
Post 17 Mar 2004, 13:56
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hitertan



Joined: 12 Mar 2004
Posts: 15
Location: China
hitertan
aaro wrote:
proc defines global testProc label and dot before testLocal makes it child label of testProc, so it comes testProc.testLocal. Now when you define global label(no dot before it) testGoto1 it changes prefix to testGoto1 so after that when you try to access .testLocal it's same as writing testGoto1.testLocal.

Solution: use local labels(labels starting with dot) inside proc's. If you need global label inside of proc you need to use label beginning with 2 dots, it's global but doesn't change current prefix for the local labels.

You should read more about labels from fasm.txt

I see!Thank you very much! Very Happy

_________________
i like assembly language and i study it in my pleasure time
tanshunquan@hotmail.com
Post 17 Mar 2004, 14:26
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