Article View: comp.arch
Article #12743Re: sizeof(char)
From: Joseph S. D. Yao
Date: Mon, 24 Nov 1986 06:40
Date: Mon, 24 Nov 1986 06:40
19 lines
1507 bytes
1507 bytes
In article <3853@mit-eddie.MIT.EDU> jbs@eddie.MIT.EDU (Jeff Siegal) writes:
>In article <9116@sun.uucp> guy@sun.uucp (Guy Harris) writes:
>>The MicroVAX-II supports the *bit field instructions of the VAX*. This is
>>*not* the same as supporting "bit addressing".
>In the general sense, no, but you can move any string of up to 32 bits
>from any bit boundry in memory to any other.
I'm surprised Guy didn't jump on this (or did we just miss it?).
The Vax EXTV/EXTZV and INSV (and CMPV/CMPZV) instructions go
between an arbitrary string of 0-32 bits and a byte-aligned
longword of 4 8-bit bytes. Not the same as any 0-32 bits to
any 0-32 bits. If I want to move bits 4-19 of word 10 to bits
5-20 of word 14, I'd have to do an EXTZV/INSV pair, clobbering
a longword somewhere in memory (or a register) as a temporary
holding place.
--
Joe Yao hadron!jsdy@seismo.{CSS.GOV,ARPA,UUCP}
jsdy@hadron.COM (not yet domainised)
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Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: arc1-ca.pugleaf.net!utzoo!mnetor!seismo!sundc!hadron!jsdy From: jsdy@hadron.UUCP (Joseph S. D. Yao) Newsgroups: comp.arch,comp.lang.c Subject: Re: sizeof(char) Message-ID: <626@hadron.UUCP> Date: Mon, 24-Nov-86 01:40:05 EST Article-I.D.: hadron.626 Posted: Mon Nov 24 01:40:05 1986 Date-Received: Mon, 24-Nov-86 21:54:54 EST References: <4617@brl-smoke.ARPA> <657@dg_rtp.UUCP> Reply-To: jsdy@hadron.UUCP (Joseph S. D. Yao) Organization: Hadron, Inc., Fairfax, VA Lines: 19 Summary: Bit field addressing?