Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!sun-barr!newstop!texsun!convex!eugene!swarren From: swarren@eugene.uucp (Steve Warren) Newsgroups: comp.arch Subject: Re: hardware complex arithmetic support Message-ID: <1549@convex.UUCP> Date: 18 Aug 89 21:23:30 GMT References: <1672@crdgw1.crd.ge.com> <4781@freja.diku.dk> <1758@crdgw1.crd.ge.com> Sender: usenet@convex.UUCP Reply-To: swarren@eugene.UUCP (Steve Warren) Organization: Convex Computer Corporation, Richardson, Tx. Lines: 20 In article <1758@crdgw1.crd.ge.com> davidsen@crdos1.UUCP(bill davidsen) writes: > Could you 'splain this to me? It sounds as if you are saying that if >one component is large in magnitude we can afford to have less precision >on the other. Hope I misunderstand what you're telling me. > bill davidsen (davidsen@crdos1.crd.GE.COM) > {uunet | philabs}!crdgw1!crdos1!davidsen >"Stupidity, like virtue, is its own reward" -me Think of it as a vector. Changing the mantissa of the component that is orders of magnitude smaller is not going to move the vector significantly. For example, if the magnitude of the smaller (call it V1) of the two components is less than the least significant bit of the larger component (call it V2), then the truncation error introduced by V2 is greater than the error introduced by eliminating V1 entirely. V1 therefore should be truncated at the least significant position in V2. --Steve ------------------------------------------------------------------------- {uunet,sun}!convex!swarren; swarren@convex.COM