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Path: utzoo!watmath!watdcsu!herbie
From: herbie@watdcsu.UUCP (Herb Chong [DCS])
Newsgroups: net.lang
Subject: Re: Runtime trapping of program bugs
Message-ID: <824@watdcsu.UUCP>
Date: Sun, 13-Jan-85 17:03:15 EST
Article-I.D.: watdcsu.824
Posted: Sun Jan 13 17:03:15 1985
Date-Received: Mon, 14-Jan-85 01:58:47 EST
References: <5143@rochester.UUCP> <19@decvax.UUCP> <481@ecsvax.UUCP> <6854@watdaisy.UUCP>
Reply-To: herbie@watdcsu.UUCP (Herb Chong [DCS])
Organization: U of Waterloo, Ontario
Lines: 24
Summary: 

In article <6854@watdaisy.UUCP> ndiamond@watdaisy.UUCP (Norman Diamond) writes:
>The Diagnose machine instruction (the real one) might generate bad parity
>among its tests, but a problem program like Watfiv would not be able to take
>advantage of it.
>
>-- Norman Diamond
the in a VM environment, a DIAGNOSE instruction is also known as a 
hypervisor call (as opposed to a supervisor call).  it traps to the
real operating system as opposed to the virtual one.  the DIAGNOSE
instruction issued by the CP component of of VM can do these things, but
in a VM, it will always go to the operating system and not the hardware.

incidentally, the DIAGNOSE instruction is a machine instruction that is
defined to be model dependent.  it is supposed to call up microcode for
debugging the hardware and things like that.

Herb Chong...

I'm user-friendly -- I don't byte, I nybble....

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