Path: utzoo!mnetor!uunet!oddjob!hao!ames!sgi!msc
From: msc@ramoth.SGI.COM (Mark Callow)
Newsgroups: comp.windows.news
Subject: Re: NeWS on a SUN, bug in translate?
Message-ID: <11753@sgi.SGI.COM>
Date: 26 Feb 88 19:47:08 GMT
References: <539@modular.UUCP> <2090@natmlab.dms.oz> <1369@vaxb.calgary.UUCP>
Sender: daemon@sgi.SGI.COM
Distribution: comp
Organization: Silicon Graphics Inc, Mountain View, CA
Lines: 29
Keywords: NeWS
Summary: the reality

In article <1369@vaxb.calgary.UUCP>, radford@calgary.UUCP (Radford Neal) writes:
>
> Fixed point numbers are automatically converted to reals as required
> in the SUN-only version of NeWS, but not in the "portable" version.
> This is because whoever re-wrote the fixed-point arithmetic routines
> in C rather than 68000 assembler decided that overflow checking wasn't
> really necesary. The fix is not hard if you've got the source - I'll
> mail it to you if you're interested.
> 
> Of course, if you're using the SUN-only version, I've mis-diagnosed
> your problem. 
> 
>     Radford Neal

The C routines were only provided as a porting aid.  Any vendor who used
them in a product should be hung out to dry.

In both Release 1.0 and a preliminary version of 1.1 there are many places
where the overflow flag simply isn't checked yet needs to be.  The
inverse delta transform is one such place.  So even if your fractional
arithmetic routines set the flag you can still get overflows.
Just try drawing out the calculator to a large size when the word
"calculator" is still showing in the calculators display.

--
From the TARDIS of Mark Callow
msc@sgi.sgi.com, ...{ames,decwrl,sun}!sgi!msc
"There is much virtue in a window.  It is to a human being as a frame is to
a painting, as a proscenium to a play.  It strongly defines its content."