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From: "Stewart Nelson" <sn@scgroup.com>
To: "lars brinkhoff" <lars@nocrew.org>
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Subject: Re: Information about the SC-40 CPU
Date: Mon, 24 Jul 2000 16:31:50 +0200
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Hi Lars,

In User Mode, our machines are essentially identical to the
extended KL-10.  There are no new instructions.  There are
some differences in intermediate results when instructions
are interrupted, and our floating point answers are often
more accurate when unnormalized operands are used.
It is intended that all KL-10 user applications will run
on our machines.  The reverse is also true, if the needed
resources are available.

In Executive Mode, there are many differences, which allow
for larger virtual and physical address spaces, and which
provide access to new devices, e.g. SCSI.  However, these
enhancements are implemented by making additional operand
formats available to existing I/O operations for paging,
device control, etc.  Again, the opcode set is identical
to that of the KL-10B.  If equipped with appropriate ancient
DEC I/O devices, our machines can run unmodified binaries
for both TOPS-10 and TOPS-20.

Do you know Peter Lö6thberg (roll@stupi.se)?  We gave some
of our SC-25 machines to his organization.  He is also a
good source for PDP-10 information.

I hope that the above description is sufficient for your needs.

Stewart Nelson


----- Original Message -----
From: "lars brinkhoff" <lars@nocrew.org>
To: <info@scgroup.com>
Sent: Monday, July 24, 2000 1:08 PM
Subject: Information about the SC-40 CPU


> Hello,
>
> I'm adding PDP-10 support to GNU binutils
> (http://sources.redhat.com/binutils/).
>
> In order to support the SC-40 CPU better, I would like to know the
> details of the instruction set supported by the SC-40.  Is such
> information available?
>
> Thank you.
>