Path: utzoo!attcan!uunet!mcvax!ukc!dcl-cs!aber-cs!pcg
From: pcg@aber-cs.UUCP (Piercarlo Grandi)
Newsgroups: comp.arch
Subject: Re: 8086 design goals
Summary: Intel WAS pascal-like language oriented... (e.g. ada)
Message-ID: <938@aber-cs.UUCP>
Date: 15 May 89 11:38:07 GMT
Reply-To: pcg@cs.aber.ac.uk (Piercarlo Grandi)
Distribution: eunet,world
Organization: Dept of CS, UCW Aberystwyth
	(Disclaimer: my statements are purely personal)
Lines: 47

In article <362@verdix.verdix.com> sbq@verdix.com (Sam Quiring) writes:
    In article <3312@bd.sei.cmu.edu> firth@sei.cmu.edu (Robert Firth) writes:
    >In article <912@aber-cs.UUCP> pcg@cs.aber.ac.uk (Piercarlo Grandi) writes:
    >
    >>Well, the problem with the Intel architecture is that it was designed for
    >>Pascal, whose pointers can only point to heap allocated objects (and no
    >>arithmetic on them is allowed).
    >
    >Leaving aside the question whether the Intel 8086 architecture was
    >"designed" for anything, let alone Pascal ...
    
    The Intel 8086 was definitely *not* designed with Pascal in mind (I did get
    a good belly laugh out of that statement).

It is cheap to have good belly laughs out of unsupported and fairly
inaccurate stetements... Try reading a book about the 286 by Isaacson and
Albert (Addison).

    It was designed to provide an
    upgrade path for 8080/8085 assembly language software (see note below), to
    have 16-bit arithmetic (the 8080 had 8-bit arithmetic), and to be able to
    address one megabyte of memory. [ .... ]

Laudable marketing goals for the 8086. Too bad that I was speaking about the
"intel" architecture, in a context of segmentation/multics. If you want additional
corroboration that the Intel guys were Pascal language oriented (e.g. ada),
consider not just the segmentation scheme, that fits Pascal exactly and causes
C problems, but also the ENTER, LEAVE and BOUND instructions of the 286, and
the ridiculous idea of putting the rings in the 286 SDs in the middle of the
pointers, thus making 32 bit address arithmetic difficult, which of course
again is horrible for C but irrelevant for Pascal like languages.

    Above all else, the 8086 was designed to make Intel a lot of money.  You may
    not like the architecture, but I'd say it met all it's design goals.

Its *marketing* goals! Ok....


Further historical note: when the 8086 and 80286 were designed, C and Unix
were but a gleam in many CS dept. eyes, and Pascal reigned...

Now that C/Unix are important, the 80386 has been given a more C/Unix 
orientation (of course by *adding* features...)
-- 
Piercarlo "Peter" Grandi           | ARPA: pcg%cs.aber.ac.uk@nsfnet-relay.ac.uk
Dept of CS, UCW Aberystwyth        | UUCP: ...!mcvax!ukc!aber-cs!pcg
Penglais, Aberystwyth SY23 3BZ, UK | INET: pcg@cs.aber.ac.uk