In <[EMAIL PROTECTED]>, on 01/24/2007
at 02:49 PM, Tom Marchant <[EMAIL PROTECTED]> said:
>As others noted, all interrupts caused a new PSW to be loaded, which
>would normally be supervisor state. The SVC instruction was the only
>way that a program could directly cause an interrupt to invoke a
>supervisor state routine.
That's still wrong. The SVC instruction caused an interrupt, period.
It was up to the SVC SLIH to index into the SVC table, etc. There was
no SVC Assist feature on the S/360.
To add to the fun, CP/67 and VM used the Diagnose instruction as a
means for a problem[1] program to cause an interrupt to invoke a
supervisor state routine. The handling was a direct parallel to the
SVC FLIH and SLIH in OS/360; CP had to determine that the interrupt
code was 2, the virtual machine was in virtual supervisor mode and the
opcode was DIAG, then use the DIAG code as an index to the proper
routine.
[1] But virtual supervisor mode.
--
Shmuel (Seymour J.) Metz, SysProg and JOAT
ISO position; see <http://patriot.net/~shmuel/resume/brief.html>
We don't care. We don't have to care, we're Congress.
(S877: The Shut up and Eat Your spam act of 2003)
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