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| From | Andrew Reilly <areilly---@bigpond.net.au> |
|---|---|
| Newsgroups | comp.arch |
| Subject | Re: Q: bit shifting |
| Date | 2011-10-08 21:28 +0000 |
| Message-ID | <9fbtj8Fs7cU1@mid.individual.net> (permalink) |
| References | <j6mnv4$8rt$1@news.albasani.net> <j6n9ij$ud2$1@dont-email.me> <j6n8l7$854$1@gosset.csi.cam.ac.uk> <j6opn1$lpa$1@dont-email.me> <j6p38a$dn7$1@gosset.csi.cam.ac.uk> |
On Sat, 08 Oct 2011 09:56:42 +0100, nmm1 wrote: > Back in the days before someone went up a mountain and was told that the > One True Direction for division was towards zero, there WERE systems > where integer division by a power of two was the same as right shifting. Right shifting signed quantities *is* division by powers of two, with truncation towards negative infinity. This is exactly what you want as the basis for division by powers of two with round to nearest, because you don't have to muck about with sign testing and differently-signed rounding biases: just add half the power of two before the shift and you're done (neglecting overflow.) Of course, right-thinking people only ever want round-to-nearest ;-) Cheers, -- Andrew
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Q: bit shifting Mok-Kong Shen <mok-kong.shen@t-online.de> - 2011-10-07 13:31 +0200
Re: Q: bit shifting nmm1@cam.ac.uk - 2011-10-07 12:17 +0100
Re: Q: bit shifting Terje Mathisen <"terje.mathisen at tmsw.no"> - 2011-10-07 17:35 +0200
Re: Q: bit shifting Stephen Fuld <SFuld@alumni.cmu.edu.invalid> - 2011-10-07 09:31 -0700
Re: Q: bit shifting nmm1@cam.ac.uk - 2011-10-07 17:16 +0100
Re: Q: bit shifting Stephen Fuld <SFuld@alumni.cmu.edu.invalid> - 2011-10-07 23:13 -0700
Re: Q: bit shifting nmm1@cam.ac.uk - 2011-10-08 09:56 +0100
Re: Q: bit shifting Andrew Reilly <areilly---@bigpond.net.au> - 2011-10-08 21:28 +0000
Re: Q: bit shifting timcaffrey@aol.com (Tim McCaffrey) - 2011-10-11 15:05 +0000
Re: Q: bit shifting Sean Case <seancase@tpg.com.au> - 2011-10-16 23:15 +1000
Re: Q: bit shifting timcaffrey@aol.com (Tim McCaffrey) - 2011-10-19 20:12 +0000
Re: Q: bit shifting Robert Wessel <robertwessel2@yahoo.com> - 2011-10-07 12:24 -0500
Re: Q: bit shifting Kai Harrekilde-Petersen <khp@harrekilde.dk> - 2011-10-07 19:27 +0200
Re: Q: bit shifting Terje Mathisen <"terje.mathisen at tmsw.no"> - 2011-10-08 10:41 +0200
Re: Q: bit shifting Kai Harrekilde-Petersen <khp@harrekilde.dk> - 2011-10-08 11:28 +0200
Re: Q: bit shifting Andrew Reilly <areilly---@bigpond.net.au> - 2011-10-08 21:38 +0000
Re: Q: bit shifting Robert Wessel <robertwessel2@yahoo.com> - 2011-10-08 22:57 -0500
Re: Q: bit shifting Terje Mathisen <"terje.mathisen at tmsw.no"> - 2011-10-09 08:18 +0200
Re: Q: bit shifting Mok-Kong Shen <mok-kong.shen@t-online.de> - 2011-10-19 15:08 +0200
Re: Q: bit shifting Michael S <already5chosen@yahoo.com> - 2011-10-11 16:41 -0700
Re: Q: bit shifting Terje Mathisen <"terje.mathisen at tmsw.no"> - 2011-10-12 07:55 +0200
Re: Q: bit shifting MitchAlsup <MitchAlsup@aol.com> - 2011-10-12 10:21 -0700
Re: Q: bit shifting Terje Mathisen <"terje.mathisen at tmsw.no"> - 2011-10-12 21:22 +0200
Re: Q: bit shifting kenney@cix.compulink.co.uk - 2011-10-13 11:00 -0500
Re: Q: bit shifting Terje Mathisen <"terje.mathisen at tmsw.no"> - 2011-10-13 20:32 +0200
Re: Q: bit shifting Mike Hore <mike_horeREM@OVE.invalid.aapt.net.au> - 2011-10-11 17:08 +1100
Re: Q: bit shifting MitchAlsup <MitchAlsup@aol.com> - 2011-10-07 12:49 -0700
Re: Q: bit shifting nmm1@cam.ac.uk - 2011-10-07 21:20 +0100
The word is devolving into 3 architectures (NOT?) "Andy \"Krazy\" Glew" <andy@SPAM.comp-arch.net> - 2011-10-07 19:48 -0700
Re: The word is devolving into 3 architectures (NOT?) Mark Thorson <nospam@sonic.net> - 2011-10-07 19:56 -0800
Re: The word is devolving into 3 architectures (NOT?) "Skybuck Flying" <Windows7IsOK@DreamPC2006.com> - 2011-10-08 04:53 +0200
Re: The word is devolving into 3 architectures (NOT?) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2011-10-08 17:26 +0000
Re: Q: bit shifting Terje Mathisen <"terje.mathisen at tmsw.no"> - 2011-10-08 10:47 +0200
Re: Q: bit shifting MitchAlsup <MitchAlsup@aol.com> - 2011-10-08 12:27 -0700
Re: Q: bit shifting Terje Mathisen <"terje.mathisen at tmsw.no"> - 2011-10-09 08:07 +0200
Re: Q: bit shifting MitchAlsup <MitchAlsup@aol.com> - 2011-10-09 12:36 -0700
Re: Q: bit shifting Terje Mathisen <"terje.mathisen at tmsw.no"> - 2011-10-10 09:06 +0200
Re: Q: bit shifting timcaffrey@aol.com (Tim McCaffrey) - 2011-10-10 15:31 +0000
Re: Q: bit shifting Terje Mathisen <"terje.mathisen at tmsw.no"> - 2011-10-10 18:13 +0200
Re: Q: bit shifting timcaffrey@aol.com (Tim McCaffrey) - 2011-10-10 20:27 +0000
Re: Q: bit shifting Terje Mathisen <"terje.mathisen at tmsw.no"> - 2011-10-10 23:45 +0200
Re: Q: bit shifting Robert Wessel <robertwessel2@yahoo.com> - 2011-10-10 17:32 -0500
Re: Q: bit shifting timcaffrey@aol.com (Tim McCaffrey) - 2011-10-11 14:58 +0000
Re: Q: bit shifting Robert Wessel <robertwessel2@yahoo.com> - 2011-10-11 11:30 -0500
Re: Q: bit shifting "Andy \"Krazy\" Glew" <andy@SPAM.comp-arch.net> - 2011-10-11 10:05 -0700
Re: Q: bit shifting timcaffrey@aol.com (Tim McCaffrey) - 2011-10-11 17:59 +0000
Re: Q: bit shifting timcaffrey@aol.com (Tim McCaffrey) - 2011-10-11 18:00 +0000
Re: Q: bit shifting Al Grant <algrant@myrealbox.com> - 2011-10-11 13:49 -0700
Re: Q: bit shifting Al Grant <algrant@myrealbox.com> - 2011-10-11 14:18 -0700
Re: Q: bit shifting Robert Wessel <robertwessel2@yahoo.com> - 2011-10-11 16:03 -0500
Re: Q: bit shifting MitchAlsup <MitchAlsup@aol.com> - 2011-10-10 09:52 -0700
Re: Q: bit shifting anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2011-10-09 12:24 +0000
Re: Q: bit shifting nmm1@cam.ac.uk - 2011-10-09 13:13 +0100
Re: Q: bit shifting Quadibloc <jsavard@ecn.ab.ca> - 2011-10-09 10:11 -0700
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