Path: utzoo!mnetor!uunet!seismo!sundc!pitstop!sun!limes
From: limes@sun.uucp (Greg Limes)
Newsgroups: comp.lang.c
Subject: Re: Indexing vs pointers
Message-ID: <51371@sun.uucp>
Date: 29 Apr 88 18:52:08 GMT
References: <1988Apr8.183815.3187@utzoo.uucp> <449@goofy.megatest.UUCP> <2200@louie.udel.EDU> <587@vsi.UUCP> <629@clinet.FI>
Reply-To: limes@sun.UUCP (Greg Limes)
Organization: Sun Microsystems, Mountain View
Lines: 11

In article <629@clinet.FI> msa@clinet.UUCP (Markku Savela) writes:
>	The question is of course: is there really any penalty in
>using indexed versions with other architectures (like motorola)?

Yes, the motorola archetecture does take a hit here. With the pointer
version, the data transfer is done using "movb a0@+,a1@+"; with the
index version, "movb a0@(0,d1:l),a1@(0,d1:l)" and "addql #1,d1".
Calculation of transfer times gets hairy, but a quick test shows that
the pointer version is about 25% faster.
-- 
   Greg Limes [limes@sun.com]				frames to /dev/fb