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From: dupuy@amsterdam.columbia.edu (Alexander Dupuy)
Newsgroups: comp.arch
Subject: Re: Wirth's "challenge" (was Re: RISC)
Message-ID: <5157@columbia.edu>
Date: Mon, 23-Nov-87 10:24:10 EST
Article-I.D.: columbia.5157
Posted: Mon Nov 23 10:24:10 1987
Date-Received: Thu, 26-Nov-87 02:36:29 EST
References: <902@mips.UUCP> <1775@cognos.UUCP>
Sender: nobody@columbia.edu
Reply-To: dupuy@amsterdam.columbia.edu (Alexander Dupuy)
Organization: Columbia University Computer Science Dept.
Lines: 22

In article <1775@cognos.UUCP> Robert Stanley writes about IBM's 801 project:
>... the compiler suite included a 370 (uh, 360) compatability mode.  In the
>compatability mode, the target architecture was System/360 and optimized
>run-time code generated compared *extremely* favourably with output from the
>PL/1 Optimizer of the day.  It is by no means obvious that the 801's
>architectural integrity had to be compromised to achieve this, with the caveat
>that perhaps 10 (or so) years ago there was less awareness.....

Perhaps I'm misunderstanding you, but do you mean to say that the 801 had a
360/370 emulation mode?  My understanding was that the PL/I (actually, PL.8)
compiler generated machine-independent intermediate code, which was transformed
by a later pass into 801 machine code.  A back-end to convert the intermediate
code into 370 machine code existed, and there were other compilers which
generated intermediate code in the same format (including a C compiler, if I
recall rightly).  I have no idea if any of these things ever saw the light of
day outside IBM, though.

@alex

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