Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!swrinde!zaphod.mps.ohio-state.edu!samsung!uunet!shelby!unix!hplabs!hpfcso!mjs
From: mjs@hpfcso.FC.HP.COM (Marc Sabatella)
Newsgroups: comp.sys.m68k
Subject: Re: 68040 status
Message-ID: <10420003@hpfcso.FC.HP.COM>
Date: 13 Feb 91 21:02:07 GMT
References: <38696@cup.portal.com>
Organization: Hewlett-Packard, Fort Collins, CO, USA
Lines: 20

>       Other than aligning the stack on a 16-byte boundary, and aligning all
>       external data modules on a similar boundary, how does a compiler take
>       advantage of the MOVE16 instruction?

Not very useful in ordinary code generation.  Structure assignment comes to
mind.  A compiler that has never heard of it is probably not severely
hampered.  In implementation of library functions, it has obvious uses for
memcpy, et al, but those are hand coded assembly if you care about speed
anyhow, so again, the compiler need not generate it.

The kinds of things a compiler could do to take advantage of the '040 are
aligning things on 8 byte (half cache line) boundaries, avoiding addressing
modes that tie up the integer unit, and instruction scheduling to keep the
pipeline flowing.

--------------
Marc Sabatella (marc@hpmonk.fc.hp.com)
Disclaimers:
	2 + 2 = 3, for suitably small values of 2
	Bill and Dave may not always agree with me