Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!wuarchive!zaphod.mps.ohio-state.edu!mips!daver!bungi.com!news
Newsgroups: comp.sys.nsc.32k
Subject: Re: Bug in minix library setjmp.s; lots of GNU tools diffs available
Message-ID: <9102072159.AA02808@halsoft>
Date: 7 Feb 91 21:59:38 GMT
Sender: news@daver.bungi.com
Lines: 28
Approved: news@daver.bungi.com

Ian writes:
>Jyrki Kuoppala writes:
> - When porting emacs to pc532-Minix, I noticed there's a bug in the
> - setjmp library routine - it doesn't save registers r3-r7 (and f4-f7)
> - which I think it should do.
...
>I believe in ANSI C, there is no requirement to save registers in setjump.
>Variables which have to be accessed after the setjump should be marked
>volatile. Yes, some people have said that is ugly and nor the way it
>should be done, but I pretty sure, that is the way it is!

I write: Ian is correct.  Nevertheless all of the following compilers
produce the result that Jyrki K's claims is correct:

	Gcc on 386
	Gcc on Sun-3 (68020)
	Cc on 386 (pcc based)
	Cc on Sun (probably pcc based)
	Microsoft C (claims to be ANSI compatible)

So it seems that's the way it isn't.

I suspect that register variables ought to be preserved despite what the
ANSI standard says, particularly since well optimized C compilers put
everything they can into registers whether or not they are declared
register.

Jonathan Ryshpan		<...!uunet!hitachi!jon>