how i can return value from macro? something like EXITM.

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dead_body

Joined: 21 Sep 2005
Posts: 187
Location: Ukraine,Kharkov

dead_body 21 Sep 2005, 08:22

subj. can i do it in fasm now, or it will be in future? Question

//sorry for bad english Embarassed

21 Sep 2005, 08:22

revolution
When all else fails, read the source

Joined: 24 Aug 2004
Posts: 20430
Location: In your JS exploiting you and your system

revolution 21 Sep 2005, 08:56

Code:

macro some_macro return_variable,[parameters] {
return_variable = something
}

some_macro the_value,1,2,3,4
mov eax,the_value

21 Sep 2005, 08:56

dead_body

Joined: 21 Sep 2005
Posts: 187
Location: Ukraine,Kharkov

dead_body 21 Sep 2005, 09:17

oh,sorry. now i'll try to explain what i want using an example.

I have:

Code:

macro strlen    arg,arg2        {       push arg
                                                Call GetStringLength ;simple proc
                                                if arg2 eq
                                                                        
                                                else
                                                        add eax,arg2
                                                end if
                                        }

and i use it like this:

Code:

strlen edi

and i need:

Code:

mov ecx,strlen edi

how can i do this? if can Sad

21 Sep 2005, 09:17

revolution
When all else fails, read the source

Joined: 24 Aug 2004
Posts: 20430
Location: In your JS exploiting you and your system

revolution 21 Sep 2005, 09:30

Code:

macro strlen soure,op {
push source
Call GetStringLength ;simple proc
op,eax
}
strlen edi,add ebx
strlen edi,mov ecx

21 Sep 2005, 09:30

vid
Verbosity in development

Joined: 05 Sep 2003
Posts: 7105
Location: Slovakia

vid 21 Sep 2005, 10:47

tis isn't possible in FASM. anyway "macro" means "macroinstruction", purpose of "macro" is to emulate instruction. what you want is called inline macro, i suggest creating macro for declaring string, which also creates constant with string size, like

Code:

struc string [value]
{common
  local ..here
  ..here:
  . db value
  siozeof#. = $ - ..here
}
my_string string 'aaaaaaaa'
mov ecx,sizeof.my_string

or you can even overload "db" itself:

Code:

struc db [value]
{common
  local ..here
  ..here:
  . db value
  siozeof#. = $ - ..here
}
my_string db 'aaaaaaaa',0
my_data db 10,50,'abc',0
mov ecx,sizeof.my_string
mov eax,sizeof.my_data

this creates sizeof.<name> for everything defined with "db".

For non-constant string, i would suggest this:

Code:

macro strlen where,what
{
  if !(where eq eax)
     push eax
  end if
  invoke GetStringLength,what
  if !(where eq eax)
    mov where,eax
    pop eax
  end if
}
strlen eax,my_string ;puts length of "my_string" to eax

Last edited by vid on 21 Sep 2005, 10:54; edited 2 times in total

21 Sep 2005, 10:47

dead_body

Joined: 21 Sep 2005
Posts: 187
Location: Ukraine,Kharkov

dead_body 21 Sep 2005, 10:47

Code:

 
strlen edi,add ebx 
strlen edi,mov ecx

but it looks not very readeble.
Maybe in future,when fasm preprocessor will be more powerfull,
(exitm <eax>) will be created, am I right Tomasz Grysztar? Question

revolution
great thanks to you. You variant is better,yet. Wink

21 Sep 2005, 10:47

vid
Verbosity in development

Joined: 05 Sep 2003
Posts: 7105
Location: Slovakia

vid 21 Sep 2005, 10:55

dead_body: seems we replied at the same time, don't miss my reply Wink

IMHO there's no reason to use macro for purpose, 2 extra lines are not problem, and it is more readable than looking for what your macro does etc.

21 Sep 2005, 10:55

Tomasz Grysztar

Joined: 16 Jun 2003
Posts: 8357
Location: Kraków, Poland

Tomasz Grysztar 21 Sep 2005, 10:56

No, inlining the macros is something against the fasm's concept. The macro in fasm is just a special kind of "mnemonic", which gets converted into chain of other lines by preprocessor. Just like each assembly language instruction spans one line, the macroinstruction spans one line.

Look at the macros in extended Win32 header (especially the "pushd") to see how this principle affects the solutions.

21 Sep 2005, 10:56

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