Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!ames!lamaster
From: lamaster@ames.arc.nasa.gov (Hugh LaMaster)
Newsgroups: comp.arch
Subject: Re: String length hardware
Message-ID: <21822@ames.arc.nasa.gov>
Date: 14 Feb 89 19:40:12 GMT
References: <8882@alice.UUCP> <13121@steinmetz.ge.com>
Organization: NASA - Ames Research Center
Lines: 15

The Cyber 205 provides an address/length form of descriptor in hardware
which works with all vector data types.  Unfortunately, the length field
is only 16 bits long, so the longest string you could have would be of
65535.  This really hurts on floating point arrays, though, because now
some arrays are that big.  (In the late 60's, when the ISA was defined,
512K of Core Memory was a BIG NUMBER.)  The hardware descriptor vehicle
is excellent, in my opinion.  The lesson: pick a big number and then
at least double the number of bits.


-- 
  Hugh LaMaster, m/s 233-9,  UUCP ames!lamaster
  NASA Ames Research Center  ARPA lamaster@ames.arc.nasa.gov
  Moffett Field, CA 94035     
  Phone:  (415)694-6117