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To: soltesz AT hotmail DOT com, djgpp AT delorie DOT com
From: Nate Eldredge <nate AT cartsys DOT com>
Subject: Re: gcc bug (when optimizing)
Date: Fri, 22 May 1998 20:42:29 -0700
Message-ID: <19980523034225.AAB10307@ppp110.cartsys.com>
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At 10:09  5/23/1998 +0200, Archee/CoNTRACT wrote:
>hello there !
>
>I have a big problame with inline asm.
>When I have a procedure, I use __asm__ ("...."), there are jumps in
>the asm statement.
>
>When I set option -O9, and I call the procedure sometimes(more than one)
>I got an asssembler error after gcc putted my code into a .S file and
>called
>as.exe I got a message like this:
>
> SIMBOL ALREADY DEFINED...
>
>When I see it by issuing the following command:
>gcc -O9 -S code.c
>
>I can see, it builited my __asm__ code sometimes in the code, it did not
>called it with call.
>
>I think it is an optimizing feature, because call is a waste of speed.
>
>I donwanna disable that optimizing feature.
>
>  How can I use local simbols in gcc inline asm ?

Right. This is because with -O3 or above, functions can be inlined. If you
use a label in your asm, and it's inlined multiple times, the function will
be multiply defined, and the assembler will barf.

Solution: Use local labels. See the Info node "as" "Symbols" "Symbol names".
Basically, the labels get single-digit names, and you reference them with
"f" or "b" depending on whether the label is forward or back. Example:

0:
  jmp 0b /* Infinite loop */

Nate Eldredge
nate AT cartsys DOT com