Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!ucbvax!agate!labrea!polya!rokicki
From: rokicki@polya.Stanford.EDU (Tomas G. Rokicki)
Newsgroups: comp.sys.amiga.tech
Subject: Re: A68k and Manx AS
Message-ID: <8979@polya.Stanford.EDU>
Date: 5 May 89 17:52:59 GMT
References: <221@mindlink.UUCP> <262@xdos.UUCP>
Sender: Tomas G. Rokicki <rokicki@polya.Stanford.EDU>
Reply-To: rokicki@polya.Stanford.EDU (Tomas G. Rokicki)
Organization: Stanford University
Lines: 17


>>        - Bcc is converted to Bcc.S if possible (for backward
>>            references only - forward references are too hard :-).

>There were some assemblers on the PDP 11 (long ago, V6 Unix) that did
>the forward references, too. Problematic due to an apparent necessity for
>an indefinite number of passes or the equivalent, but when your text memory
>space is only 64K I guess it may seem worth it.

If you have memory available, it's not *that* difficult.  Simply maintain
a list of `candidate' branches during the first pass.  A branch is a
candidate if --> it's not already short and there isn't too much unmoveable
code between it and it's target.  Now, simply run multiple passes over
your branch list in *memory*, changing any appropriate ones to short, until
it can no longer be done.  Now go back and update your symbol table.

tom