Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!killer!texbell!sugar!ficc!uunet!kddlab!titcca!sragwa!wsgw!socslgw!diamond
From: diamond@csl.sony.JUNET (Norman Diamond)
Newsgroups: comp.lang.c
Subject: Re: Argument Passing in C (Stacks)
Message-ID: <10036@socslgw.csl.sony.JUNET>
Date: 11 Oct 88 23:41:00 GMT
References: <705.2339B3D8@stjhmc.fidonet.org> <699@wsccs.UUCP> <202@obie.UUCP>
Organization: Sony Computer Science Laboratory Inc., Tokyo, Japan
Lines: 27

In <202@obie.UUCP>, wes@obie.UUCP (Barnacle Wes) writes (almost):

> POP	MACRO	a
> 	L	R5,a
> 	LA	R5,4(R5)
> 	MEND
 
> PUSH	MACRO	a
> 	S	R5,=F'4'
> 	ST	R5,a
> 	MEND

> The problem with these macros is that they are not atomic.  I can't
> think of any straightforward reasons why this is a problem, but I'm
> sure it would cause problems somewhere, somehow.

No problems should be caused by not being atomic.  Real problems are
caused when programmers carelessly use machine instructions such as
POP a   or   PUSH a    and think that they are atomic.  In fact,
such instructions are also non-atomic (nearly always if not always)
and careless programmers create obscure bugs in multiprocessing
systems.
-- 
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  The above opinions are my own.   |   Norman Diamond
  If they're also your opinions,   |   Sony Computer Science Laboratory, Inc.
  you're infringing my copyright.  |   diamond%csl.sony.jp@relay.cs.net