backward label undefined

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CandyMan

Joined: 04 Sep 2009
Posts: 414
Location: film "CandyMan" directed through Bernard Rose OR Candy Shop

CandyMan 03 Apr 2017, 07:44

Code:

if Z-Y>0
@@:
else
@@:
end if
jnz @B  ;undefined symbol
Y:
db 0
Z:

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03 Apr 2017, 07:44

Tomasz Grysztar

Joined: 16 Jun 2003
Posts: 8466
Location: Kraków, Poland

Tomasz Grysztar 03 Apr 2017, 08:28

The @@ label implementation in fasm 1 is in the parser stage before the actual assembly takes place and therefore it is not affected by IF conditions. The "@B" in your sample refers to the second "@@" regardless whether the line later is assembled or not.

You can look at it as if the parser created an unique name for each @@ label (like what fasm's preprocessor does for LOCAL labels) and this is how your sample then looks like to the assembler:

Code:

if Z-Y>0
anonymous1:
else
anonymous2:
end if
jnz anonymous2
Y:
db 0
Z:

The new fasmg engine has no such limitations since it got rid of a separate stages.

Last edited by Tomasz Grysztar on 03 Apr 2017, 08:35; edited 1 time in total

03 Apr 2017, 08:28

CandyMan

Joined: 04 Sep 2009
Posts: 414
Location: film "CandyMan" directed through Bernard Rose OR Candy Shop

CandyMan 03 Apr 2017, 08:35

all right, I thank for the explanation.

_________________
smaller is better

03 Apr 2017, 08:35

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