Path: utzoo!mnetor!uunet!nbires!hao!ames!pasteur!ucbvax!ulysses!cjc
From: cjc@ulysses.homer.nj.att.com (Chris Calabrese[rs])
Newsgroups: comp.lang.c
Subject: Re: register unions
Message-ID: <10075@ulysses.homer.nj.att.com>
Date: 15 Feb 88 16:00:34 GMT
References: <1229@eneevax.UUCP>
Distribution: comp.lang.c
Organization: AT&T Bell Laboratories, Murray Hill
Lines: 19
Keywords: registers, unions
Summary: register only used for int's

In article <1229@eneevax.UUCP>, noise@eneevax.UUCP (Johnson Noise) writes:
> 
> similarity to 68k assembly.  Unfortunately, all the compilers I have
> tried (including pcc) will not allocate unions in registers.  My initial
> suspicion is that most compilers simply do not allow anything other than
> basic types to be allocated in registers.  I realize that combining
> pointers and non-pointers in 68k systems is not possible, but I don't
> intend to do that.  I don't see any immediate problems in allowing
> such a declaration (with checks on 68k's).

The official AT&T version of the K&R portable C compiler only
supports register allocation of int's.  All other types are
silently assigned to core.  This, however, is something which
is supposed to change in the near future, at leas according to
my documentation.

	Chris Calabrese
	AT&T Bell Labs
	ulysses!cjc