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From: henry@utzoo.UUCP (Henry Spencer)
Newsgroups: comp.lang.c
Subject: Re: bit-field pointers / arrays
Message-ID: <7433@utzoo.UUCP>
Date: Fri, 19-Dec-86 13:30:46 EST
Article-I.D.: utzoo.7433
Posted: Fri Dec 19 13:30:46 1986
Date-Received: Fri, 19-Dec-86 13:30:46 EST
References: <2937@bu-cs.BU.EDU> <321@bms-at.UUCP>, <1170@ucbcad.BERKELEY.EDU>
Organization: U of Toronto Zoology
Lines: 19

> Here is a list of processors which I know to have
> bit-field instructions that I can't get at from 'C':
> 
> ...
> 	PDP-11	(From previous posting)

Uh, really?  Funny how I've never noticed them in all my years of PDP-11
programming.  Please identify them by opcode.  A quick look doesn't find
any relevant previous posting.

The 11 does have instructions that one can't get to from C, mostly fairly
useless or ultra-specialized odds and ends, but bit-fields are absent.
The byte is the smallest unit that the 11 architecture is aware of.  (Even
the BCD arithmetic in the grotesque "commercial instruction set", available
as an add-on for a few of the later 11s, wants numbers to begin and end
on byte boundaries.)
-- 
				Henry Spencer @ U of Toronto Zoology
				{allegra,ihnp4,decvax,pyramid}!utzoo!henry