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From: rrh@cs.washington.edu (Robert R. Henry)
Newsgroups: comp.compilers
Subject: 801 and Berkeley RISC
Message-ID: <1990Feb11.221007.2571@esegue.segue.boston.ma.us>
Date: 11 Feb 90 22:10:07 GMT
Sender: compilers-sender@esegue.segue.boston.ma.us
Reply-To: rrh@cs.washington.edu (Robert R. Henry)
Organization: Compilers Central
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Approved: compilers@esegue.segue.boston.ma.us

The compilers moderator writes in response to a message by dgb:
> [Keep in mind that the IBM 801 project, the original RISC work, closely
> involved John Cocke, Fran Allen, and other compiler experts.  The PL.8
> compiler that was part of that effort is still a serious contender for
> world's best optimizing compiler.  It has been retargeted for lots of
> different machines, evidently without a whole lot of work.  The
> Berkeley project as far as I can tell involved no compiler people at
> all, which appears to me to be the reason that they invented register
> windows, being unaware of how good a job of register management a
> compiler can do.  -John]

Could you provide leads on "lots of different machines"?  My understanding
of the 801 compiler (now very very dated) is that ported versions of the
compiler treated microprocessors as a RISC machine, and ended up doing
a lousy job of using addressing modes.

Register windows >were< invented by two compiler people, Peter Kessler
and Dan Halbert; they were looking for an easy way to pass parameters
in order to simplify that part of the compiler.

Robert Henry
[I'll look it up, see subsequent article.  -John]
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