How to define a table of function pointers using macros?

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ronware

Joined: 08 Jan 2004
Posts: 179
Location: Israel

ronware 26 Dec 2004, 06:18

I am interested in using macros to help automate the creating of a table of function pointers.

The usage would be like this:

Code:

function 'function1'
   ... some asm code ...
   ret

function 'function2'
    .... some asm code
    ret

... somewhere later, declare the function table
function_table

The 'function' macros might be over several source files; what I want is that they allow me to use 'function_table' later, which will create an array with the function names and offsets.

Is something like this possible with FASM macro language?

26 Dec 2004, 06:18

JohnFound

Joined: 16 Jun 2003
Posts: 3499
Location: Bulgaria

JohnFound 26 Dec 2004, 08:12

Of course it is possible, with only limitation that the pointer table must stay after the last function.
The main idea is to have one globa symbolic costant and on every "functions" to add the function name to the constant:

Code:

   FunctionList equ FunctionList, functionName

At the end you will have FunctionList containing all functions names separated with commas. Then you have to define second macro "BuildFunctionTable" and to pass to it this list:

Code:

macro BuildFunctionsTable [func] {
forward
  dd func
}

This is very simplified description. You can look at "globals.inc" macroses from the project Fresh - they use similar technique to make global data definitions.

Regards.

26 Dec 2004, 08:12

ronware

Joined: 08 Jan 2004
Posts: 179
Location: Israel

ronware 27 Mar 2005, 23:00

Hi, JohnFound -

Since you posted that response, I had gone to using Perl to extract the information the way I want. But now I am revisiting the problem, and I am getting more questions than answers Sad

The attached file 'test.asm' illustrates what I am trying to do, and the problem I am having.

Basically, I have a macro "addtolist [a,b]" which I call like "addtolist 9,'nine'". It is supposed to append the values to some list (an EQU).

Then I try to process that list using the 'table' macro, which is declared as "table [xt,nm]" but things do not work as I expect (at all). For one thing, the types of the values passed in seem wrong to me.

I would appreciate any help you can provide me.

Thanks!

Description:		Download
Filename:	test.asm
Filesize:	941 Bytes
Downloaded:	483 Time(s)

27 Mar 2005, 23:00

ronware

Joined: 08 Jan 2004
Posts: 179
Location: Israel

ronware 15 Jun 2005, 16:25

Arggh!

My table macro was like this:

Code:

macro mlist nam,xt { macrolist fix macrolist,xt,nam }

And with 1.62, this doesn't work any more Sad

What is intended is that whenever 'mlist' is invoked, it adds 'name,xt' to the 'macrolist'. So that when 'macrolist' is passed to a table builder macro, it can create the proper table from it.

What is the right thing to do with the new 'match', or can I still use 'fix' just in some different way?

15 Jun 2005, 16:25

Tomasz Grysztar

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

Tomasz Grysztar 15 Jun 2005, 19:23

Read the updated manual, especially the section 2.3.7 which contains exactly the information you need.

15 Jun 2005, 19:23

ronware

Joined: 08 Jan 2004
Posts: 179
Location: Israel

ronware 15 Jun 2005, 19:47

Indeed, it works! Thanks.

15 Jun 2005, 19:47

ronware

Joined: 08 Jan 2004
Posts: 179
Location: Israel

ronware 10 Sep 2005, 01:12

Now I would like to add some more information to the list. Basically, I want to know how big the function is. Using something like this:

function 'name', _internal_name
mov ebx, eax
...etc ....
endfunction

What I want is that 'endfunction' should figure out how big the function was (in bytes) and append that information to the function list. But sadly, I'm encountering resistance Sad

Any ideas?

10 Sep 2005, 01:12

Reverend

Joined: 24 Aug 2004
Posts: 408
Location: Poland

Reverend 11 Sep 2005, 13:26

Code:

macro endp name {
 endp
 sizeof.#name = $-name
}

; usage: instead of lone endp add function name after it
proc    function1
        ; normal code here
endp    function1

        mov     eax, sizeof.function1

11 Sep 2005, 13:26

ronware

Joined: 08 Jan 2004
Posts: 179
Location: Israel

ronware 15 Sep 2005, 21:42

Thanks, I ended up doing something like that. I was hoping for something more elegant - where the current word was saved in the 'proc' macro, and reused in the 'end' macro. But I had trouble getting that part to work correctly.

15 Sep 2005, 21:42

blueowl2

Joined: 30 Oct 2005
Posts: 4

blueowl2 30 Oct 2005, 14:45

JohnFound wrote:

Of course it is possible, with only limitation that the pointer table must stay after the last function.
The main idea is to have one globa symbolic costant and on every "functions" to add the function name to the constant:
Code:
   FunctionList equ FunctionList, functionName
    
At the end you will have FunctionList containing all functions names separated with commas. Then you have to define second macro "BuildFunctionTable" and to pass to it this list:
Code:
macro BuildFunctionsTable [func] {
forward
  dd func
}
    
This is very simplified description. You can look at "globals.inc" macroses from the project Fresh - they use similar technique to make global data definitions.

Regards.

Should that code work? In my code there is a problem with that, namely that only one entry of the list will be written:

Code:

macro addtolabellist
{ local _label
  if defined labellist
  labellist equ labellist,_label
  else
  labellist equ _label
  end if
  _label: }

macro writelabellist [label]
{ forward
  dd label }

nop
addtolabellist
nop
addtolabellist
nop
addtolabellist

writelabellist labellist

Any idea's? :)

30 Oct 2005, 14:45

Tomasz Grysztar

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

Tomasz Grysztar 30 Oct 2005, 15:03

Read section 2.3.7 of manual.

30 Oct 2005, 15:03

blueowl2

Joined: 30 Oct 2005
Posts: 4

blueowl2 30 Oct 2005, 17:50

[quote="Tomasz Grysztar"]Read section [url=http://flatassembler.net/docs.php?article=manual#2.3.7]2.3.7[/url] of manual.[/quote]

Yes, thankyou, I already read it in your previous post. I tried it with:

[code]macro addtolabellist
{ local _label
if defined labellist
labellist equ labellist,_label
else
labellist equ _label
end if
_label: }

nop
addtolabellist
nop
addtolabellist
nop
addtolabellist

macro writelabels { match aparam, labellist \{ writelabel aparam \} }
macro writelabel [tparam] { forward dd tparam }
writelabels[/code]

But it does not seem to replacing [i]aparam[/i] with the actual value of labellist.

30 Oct 2005, 17:50

Tomasz Grysztar

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

Tomasz Grysztar 30 Oct 2005, 21:55

Go back to reading it and note what it says about mixing preprocessor's and assembler's features.

Hint: use "match", not "if".

30 Oct 2005, 21:55

blueowl2

Joined: 30 Oct 2005
Posts: 4

blueowl2 02 Nov 2005, 19:02

Something like:

[code]V fix {
macro addtolabellist
\{ local _label
_label:
match any, labellist \\\{ labellist equ labellist,_label \\\}
match , labellist \\\{ labellist equ _label \\\} \}
}
V

nop
addtolabellist
nop
addtolabellist
nop
addtolabellist

macro writelabels { match aparam, labellist \{ writelabel aparam \} }
macro writelabel [tparam] { forward dd tparam }
writelabels[/code]

:)? Sorry, I guess I need more then a hint.

02 Nov 2005, 19:02

blueowl2

Joined: 30 Oct 2005
Posts: 4

blueowl2 03 Nov 2005, 14:21

After a lot of trying, i got the following macro working. The question is if the "definelabel" macro is necessary, or could be integrated into addtolabellist. Thanks in any case. :)

[code]macro definelabel name { name#.list equ }

macro addtolabellist name
{ item = $
match any, name#.list \{ name#.list equ name#.list,item \}
match , name#.list \{ name#.list equ item \}
}

definelabel some
nop
addtolabellist some
nop
addtolabellist some
nop
addtolabellist some

macro writelabels { match aparam, some.list \{ writelabel aparam \} }
macro writelabel [tparam] { forward dd tparam }
writelabels[/code]

03 Nov 2005, 14:21

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