Article View: comp.arch
Article #21144Re: unconventional architectures
From: Bob Larson
Date: Wed, 10 May 1989 00:41
Date: Wed, 10 May 1989 00:41
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1615 bytes
In article <13688@watdragon.waterloo.edu> tbray@watsol.waterloo.edu (Tim Bray) writes:
>Hear ye! Segments are evil. If my usable address space is N, it is a priori
>*wrong* to assume that I won't mind dealing with segments of any size < N.
Segments are NOT evil, you just havn't seen an implmentation of them you like.
For a segmented pointer format to be used for the next decade or so I would
propose:
bit offset from segment base: 64 bits
segment number: 32 bits
protection ring: 16 bits
misc flags: 16 bits
(includes info like non-snapped pointer for dynamic linking, etc.)
If the offset field of the pointer is big enough to address all your
virtual address space, segmentation is NOT a limit. (On the other hand,
poorly designed segments (intel) are horid.)
--
Bob Larson Arpa: blarson@skat.usc.edu
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Path: arc1-ca.pugleaf.net!utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!bloom-beacon!usc!skat.usc.edu!blarson From: blarson@skat.usc.edu (Bob Larson) Newsgroups: comp.arch Subject: Re: unconventional architectures Message-ID: <17134@usc.edu> Date: 10 May 89 00:41:46 GMT References: <112@centaure.UUCP> <422@unicads.UUCP> <11579@cgl.ucsf.EDU> <89May6.165030edt.10782@ephemeral.ai.toronto.edu> <1989May6.234007.23517@utzoo.uucp> <89May7.001514edt.39763@neat.ai.toronto.edu> <40284@think.UUCP> <13688@watdragon.waterloo.edu> Sender: news@usc.edu Reply-To: blarson@skat.usc.edu (Bob Larson) Organization: USC AIS, Los Angeles Lines: 25