Path: utzoo!utgpu!water!watmath!clyde!cbosgd!ihnp4!chinet!dag
From: dag@chinet.UUCP (Daniel A. Glasser)
Newsgroups: comp.lang.c
Subject: Re: what C needs -- packed structures
Message-ID: <2103@chinet.UUCP>
Date: 12 Jan 88 16:05:51 GMT
References: <8801071842.AA04669@decwrl.dec.com> <2083@chinet.UUCP> <519@cresswell.quintus.UUCP>
Reply-To: dag@chinet.UUCP (Daniel A. Glasser)
Organization: Chinet - Public Access Unix
Lines: 23

In article <519@cresswell.quintus.UUCP> ok@quintus.UUCP (Richard A. O'Keefe) writes:
+In article <2083@chinet.UUCP>, dag@chinet.UUCP (Daniel A. Glasser) writes:
++ struct yerks { char y_foo; int *y_fie; char y_poo; };
++ struct yerks *w;
++ int i;
++ i = *w->y_fie;
+He claims that this assignment would turn into 9 M680x0 instructions.
+Wrong.  It can be coded in three:
+	movl	_w, a0
+	movl	1(a0), a0
+	movl	(a0), _i
[rest of article omitted]

I specified M68000.  I know that the 68020 relaxes this restriction.
I also think that the T-11 (lsi-11 on a single 8085 style chip) relaxes
this restriction.  There are still lots of 68000 and 68010 chips in use
out here.  Richard's example causes an address error on the M68000.
-- 
					Daniel A. Glasser
					...!ihnp4!chinet!dag
					...!ihnp4!mwc!dag
					...!ihnp4!mwc!gorgon!dag
	One of those things that goes "BUMP!!! (ouch!)" in the night.