Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!usc!julius.cs.uiuc.edu!ux1.cso.uiuc.edu!ux1.cso.uiuc.edu!aglew From: aglew@crhc.uiuc.edu (Andy Glew) Newsgroups: comp.arch Subject: Re: Alignment on RS/6000 Message-ID: Date: 26 Nov 90 21:02:06 GMT References: <893@sibyl.eleceng.ua.OZ> <46760@apple.Apple.COM> <897@sibyl.eleceng.ua.OZ> Sender: news@ux1.cso.uiuc.edu (News) Organization: Center for Reliable and High-Performance Computing University of Illinois at Urbana Champaign Lines: 13 In-Reply-To: ian@sibyl.eleceng.ua.OZ's message of 25 Nov 90 00:28:49 GMT >In a well behaved program they are extremely rare. Therefore, if they occur >you almost certainly have a bug and you might as well core dump. Once one >occurs, they tend to be contageous, so that soon your program is trapping >on every floating point operation. *That* is what makes it take "forever". > >The output of such a program is useless. The results are meaningless and >worse, they give you no clue as to where the problem might be. A core dump >is preferable except maybe in commercial software, and even then it only >gives an illusion of robustness. Hmmm.... what should a spreadsheet do when the user has said to divide by 0? -- Andy Glew, a-glew@uiuc.edu [get ph nameserver from uxc.cso.uiuc.edu:net/qi]