Is it possible to insert code from later in the file?

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Plue

Joined: 15 Dec 2005
Posts: 151

Plue 29 Nov 2006, 14:51

Is it possible to trick fasm into doing something like this?

Code:


<insert SymbolName here>

Macro SymbolName {
   Simple list of instructions
   ..
}

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29 Nov 2006, 14:51

vid
Verbosity in development

Joined: 05 Sep 2003
Posts: 7105
Location: Slovakia

vid 29 Nov 2006, 15:33

unfortunatelly, no.

only with some very dirty tricks, and i am not sure about it.

29 Nov 2006, 15:33

revolution
When all else fails, read the source

Joined: 24 Aug 2004
Posts: 19256
Location: In your JS exploiting you and your system

revolution 29 Nov 2006, 17:47

Macros cannot be forward referenced, not ever, never, no chance, not possible. Except if you rewrite fasm.

29 Nov 2006, 17:47

vid
Verbosity in development

Joined: 05 Sep 2003
Posts: 7105
Location: Slovakia

vid 29 Nov 2006, 18:00

but you can store data in variables and forward reference variables... that's what i meant with "very dirty tricks"

29 Nov 2006, 18:00

Tomasz Grysztar

Joined: 16 Jun 2003
Posts: 8135
Location: Kraków, Poland

Tomasz Grysztar 29 Nov 2006, 18:28

This "dirty trick" is closely related to this problem: http://board.flatassembler.net/topic.php?t=5934

29 Nov 2006, 18:28

Plue

Joined: 15 Dec 2005
Posts: 151

Plue 29 Nov 2006, 19:17

revolution wrote:

Macros cannot be forward referenced, not ever, never, no chance, not possible. Except if you rewrite fasm.

As I said, I don't need full macro functionality, only a simple list of instructions.

It looks like what I want to do is actually possible by forward-referencing a variable from a macro and then generating the instructions from that macro. But I managed to do it some other way by buffering up all the code in between, writing the simple list of instructions without going through the buffer, and then writing the buffer. (I am writing a compiler.)

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Violets are blue
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29 Nov 2006, 19:17

revolution
When all else fails, read the source

Joined: 24 Aug 2004
Posts: 19256
Location: In your JS exploiting you and your system

revolution 29 Nov 2006, 20:39

Plue wrote:

As I said, I don't need full macro functionality, only a simple list of instructions.

Where did you say that?

Plue wrote:

I am writing a compiler.

Do you have a website where we can see your compiler?

29 Nov 2006, 20:39

Plue

Joined: 15 Dec 2005
Posts: 151

Plue 29 Nov 2006, 21:44

revolution wrote:

Plue wrote:
As I said, I don't need full macro functionality, only a simple list of instructions.
Where did you say that?

Ok, maybe I didn't say it very clearly, but:

Macro SymbolName {
Simple list of instructions < Here!!! Wink

..
}

Quote:

Plue wrote:
I am writing a compiler.
Do you have a website where we can see your compiler?

Yup! http://lasic.frac.dk/forum/

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29 Nov 2006, 21:44

Goplat

Joined: 15 Sep 2006
Posts: 181

Goplat 30 Nov 2006, 00:41

revolution wrote:

Macros cannot be forward referenced, not ever, never, no chance, not possible.

Sounds like a challenge Wink

Call this file fwdmac.asm

Code:

match =1,second {
        mymacro
}

match =second,second {
        macro mymacro \{
                db "blah"
        \}

        second equ 1
        include 'fwdmac.asm'
}

30 Nov 2006, 00:41

vid
Verbosity in development

Joined: 05 Sep 2003
Posts: 7105
Location: Slovakia

vid 30 Nov 2006, 08:03

Goplat:

good one....

30 Nov 2006, 08:03

revolution
When all else fails, read the source

Joined: 24 Aug 2004
Posts: 19256
Location: In your JS exploiting you and your system

revolution 30 Nov 2006, 11:16

Goplat wrote:

Sounds like a challenge

I like it. Now that is really thinking outside the box.

Okay, I change my statement a little. How about this:

Macros cannot be forward referenced in a useful way, not ever, never, no chance, not possible.

Hehe, now the challenge is to make it useful ... Wink

30 Nov 2006, 11:16

Mr_Silent

Joined: 25 Apr 2006
Posts: 30

Mr_Silent 30 Nov 2006, 15:44

2 revolution: What is your meaning of "useful"?

Code:

.maincode fix _main
macro _main
 {
  macro tag_main {
 }
;------------------------------------------------------------------------------
.postdef fix } _post
macro _post
 {
  macro tag_post {
 }
;------------------------------------------------------------------------------
.end fix } _end
macro _end
 {
  tag_post
  tag_main
 }
;//////////////////////////////////////////////////////////////////////////////

.maincode
 zb sb1,'a','b','z','x'
 zd sd1,'a','b','z','x'

.postdef

 macro zd p1,[p2]
  \{
   \common
   label p1
   \forward
   dd p2
   \common dd 0
  \}

 macro zb p1,[p2]
  \{
   \common
   label p1
   \forward
   db p2
   \common db 0
  \}

.end

30 Nov 2006, 15:44

revolution
When all else fails, read the source

Joined: 24 Aug 2004
Posts: 19256
Location: In your JS exploiting you and your system

revolution 30 Nov 2006, 22:45

Mr_Silent: I think your code does not address the problem of defining the macros after you instantiate it. You code defines a few macros but does not use any of them until the final ".end" statement.

Goplat posted a nice example of reassembling the same file again that simulates defining macros after they are used, but I think it is not useful in any real program. It was all in good fun and my challenge was not anything serious. I would be delighted to see a real-world working example of Goplat's idea given above.

30 Nov 2006, 22:45

Mr_Silent

Joined: 25 Apr 2006
Posts: 30

Mr_Silent 01 Dec 2006, 06:40

revolution wrote:

I think your code does not address the problem of defining the macros after you instantiate it.

Of course, it doesn't Very Happy

. There is no such problem, Exclamation

because strait fwd-ref is impossible (with current implementation of Fasm preprocessor) Exclamation

, point. The only matter could be discussed here is how to "trick fasm into doing something like..." (see post 1).
Idea

Or did you want the community to find some critical bu... err... feature which will allow normal fwd-ref Question

01 Dec 2006, 06:40

revolution
When all else fails, read the source

Joined: 24 Aug 2004
Posts: 19256
Location: In your JS exploiting you and your system

revolution 01 Dec 2006, 12:31

Mr_Silent wrote:

Or did you want the community to find some critical bu... err... feature which will allow normal fwd-ref

Yep, I would like to see someone find a "feature". Feature finding is a hobby of mine. Wink

01 Dec 2006, 12:31

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