21 Jun
2016
21 Jun
'16
5:02 p.m.
On 06/21/2016 09:24 AM, Paul Koning wrote:
I don't recognize "ILR". The control
for central exchange (XJ
instruction) is is largely in the ECS coupler partly because some of
the exchange package state (RAX/FLX/MA) lives there, as does the
monitor mode flag. Also partly because XJ and RE/WE are 01 opcodes
that use the same address calculation. I think once you get past the
coupler into ECS itself and the ECS controller, there aren't any
execution-related bits. Not unless you count the Flag Register,
which is a set of mutexes operated on by ECS read/write operations.
ILR = "Interlock Register"
It was mutex setup, but on a per-system, rather than as a global ECS
thing like the flags register--and accessible only to PPs. Any word in
it could be read by any PP.
Either 64 or 128 bits located on PP channel 15 (octal). The only
mention that I could find of it in the bitsavers collection was for the
Cyber 74, but it was on lower Cybers as well.
http://bitsavers.informatik.uni-stuttgart.de/pdf/cdc/cyber/cyber_70/6034740…
PDF page 48.
I don't know if it was a retrofit for older 6000 systems, but it would
seem to make sense if it was. It simplified the RCH/DCH PP channel
reservation calls enormously.
--Chuck