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From: "Robert I. Eachus" <eachus@mitre.org>
Subject: Re: Compiler for Z80/6510
Date: 1999/12/13
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Robert Dewar wrote:
 
> Yes, of course, what has this to do with special instructions
> on IBM main frames to speed up APL (that is what I understood
> you to be talking about???)

    Oh, well if you wanted references to that, look at the IBM pricing
schedules for the IBM 3033 series, although the same feature was
available on other 370 series processors.

    But the basic issue is that there are instructions not part of the
instruction set on many processors, and compiler run-times often take
advantage of these features (in some cases, of necessity), while the
standard assembler for the platform has little or no support for the
same.

    While we are on the subject of the 370 architecture, another "art
form" was to program channel controllers.  I remember one matrix
multiplying routine for the 360/370 series which used the paging
controller for the swap disks to transpose matrices.  (Darn! What was
the name of the U. Michigan OS? Not MAD that was much earlier.  Was it
MTDS?)  Anyway, since we used drums instead of disks for swapping, the
code needed a bit of massaging, which was how I ran into it.
-- 

                                        Robert I. Eachus

with Standard_Disclaimer;
use  Standard_Disclaimer;
function Message (Text: in Clever_Ideas) return Better_Ideas is...