Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!rutgers!iuvax!purdue!ames!sgi!msg@fiji.sgi.com
From: msg@fiji.sgi.com (Mark Grossman)
Newsgroups: comp.sys.sgi
Subject: Re: BITBLT for 3030?
Message-ID: <37889@sgi.SGI.COM>
Date: 13 Jul 89 17:13:57 GMT
References: <8907071121.aa24621@VMB.BRL.MIL>
Sender: daemon@sgi.SGI.COM
Organization: Silicon Graphics, Inc., Mountain View, CA
Lines: 11

In article <8907071121.aa24621@VMB.BRL.MIL>, moss@BRL.MIL ("Gary S. Moss", VLD/VMB) writes:

> however:  If the destination rectangle of the rectcopy() had an X coordinate
> which was a multiple of 16 (i.e., rectopy's 5th argument), than the copy
> was *very* fast, but anything else was blindingly slow.  I don't recall if
> the source rectangle's position was a factor or not (either it wasn't or
> my source rectangle happened to be aligned).  What I used to do was allow

Actually, this speedup can be achieved by ensuring that the DIFFERENCE
between the source and destination rectangle positions is a multiple
of 16.