Code can't be generated?

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l4m2

Joined: 15 Jan 2015
Posts: 674

l4m2 19 Feb 2015, 10:55

Code:

  rept 10 i:0 {
    if ~defined int_#i
      int_#i:
        mov al,i
        iret
    end if
  }

19 Feb 2015, 10:55

revolution
When all else fails, read the source

Joined: 24 Aug 2004
Posts: 20445
Location: In your JS exploiting you and your system

revolution 19 Feb 2015, 11:04

See here:

http://board.flatassembler.net/topic.php?t=8328

19 Feb 2015, 11:04

l4m2

Joined: 15 Jan 2015
Posts: 674

l4m2 19 Feb 2015, 11:23

revolution wrote:

See here:

http://board.flatassembler.net/topic.php?t=8328

So the reason is that the definition itself made it not to define and a loop happened ?

19 Feb 2015, 11:23

baldr

Joined: 19 Mar 2008
Posts: 1651

baldr 20 Feb 2015, 20:07

l4m2,

It's all about prediction. fasm uses data from previous pass to deduce whether that symbol is going to be defined.

20 Feb 2015, 20:07

l_inc

Joined: 23 Oct 2009
Posts: 881

l_inc 20 Feb 2015, 22:31

baldr
It is more important to understand the conceptual reasoning than the technical. Conceptually the source code makes a contradictory statement that cannot be true (a label must be defined if it's not defined and must not be defined if it is), and compilation is a process of finding such conditions that all the statements in the source are true, which is not possible in this case.

_________________
Faith is a superposition of knowledge and fallacy

20 Feb 2015, 22:31

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