Article View: comp.arch
Article #22796Re: heaps of numbers (tagged immediate float formats & float usage)
From: Jim Giles
Date: Mon, 05 Mar 1990 23:36
Date: Mon, 05 Mar 1990 23:36
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From article <1990Mar5.220724.3718@Neon.Stanford.EDU>, by wilson@carcoar.Stanford.EDU (Paul Wilson): > [...] > I don't get this. It seems to me that if 8 bits gives you a range of 10**-38 > to 10**+38, then 4 bits ought to give you half as many orders of magnitude, > or about 10**-19 to 10**+19. [...] Exponent range scales as the _LOG_ (base 2) of the number of bits in the exponent. So, 8 bits gives an exponent range of (about) 2^-127 thru 2^127 - that is, about 10^-39 thru 10^39. A 4 bit exponent only gives an exponent range of about 2^-15 thru 2^15 - that is, a little more than 10^-5 thru 10^5. J. Giles
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Path: arc1-ca.pugleaf.net!utzoo!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!yale!cmcl2!lanl!lambda!jlg From: jlg@lambda.UUCP (Jim Giles) Newsgroups: comp.arch,comp.lang.lisp,comp.lang.misc,comp.lang.smalltalk Subject: Re: heaps of numbers (tagged immediate float formats & float usage) Message-ID: <14261@lambda.UUCP> Date: 5 Mar 90 23:36:42 GMT References: <1990Mar5.220724.3718@Neon.Stanford.EDU> Lines: 13