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From: "Stephen Fuld" <SFuld@alumni.cmu.edu.invalid>
Newsgroups: comp.arch
Subject: Re: Concertlina II: Full Circle
Date: Tue, 18 Jun 2024 22:42:32 -0000 (UTC)
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Thomas Koenig wrote:

> John Savard <quadibloc@servername.invalid> schrieb:
> > On Tue, 18 Jun 2024 16:17:33 -0000 (UTC), Thomas Koenig
> ><tkoenig@netcologne.de> wrote:
> >>John Savard <quadibloc@servername.invalid> schrieb:
> > 
> >>> Also, this looping instruction is strictly a way to directly
> encode >>> the FORTRAN DO loop. It does not attempt any vectorization.
> > 
> > > Which one, the FORTRAN 66 one or the one since FORTRAN 77?
> 
> > FORTRAN IV (or 66) indeed.
> 
> It was actually not defined in the standard, in practice it
> was usually implemented by a test at the bottom of the loop,
> and programs depended on that.
> 
> FORTRAN 77 fixed that, so now
> 
> 	DO 100 I=1,0
> 
> ...
>   100   CONTINUE
> 
> is executed zero times.


How does VVM handle that?  It sems you must "waste" some time, not
executing the loop body until the furst LOOP instruction tells you
whether to or not, or perhaps not actually updating the values the
first time through the loop.  Neither seems optimal.  :-(





-- 
 - Stephen Fuld 
(e-mail address disguised to prevent spam)