ICM, STCM, CLM - Off-Topic. 
Author Message
 ICM, STCM, CLM - Off-Topic.

Sorry, but I just have to tell everyone about the "ickum" and "stickum"
problems at this one company I worked for. They were taking a basic
370 "engine" and trying to develop a 3990-3 caching controller clone
with remote dual-copy capabilities. This 370 engine was essentially
a RISCed version with no floating point, nor packed decimal. And
even Divide/Multiply had to be emulated.

Bottom line for the subject instructions was that if the second operand
of any storage fetch crossed a cache-line boundary (16 bytes in this
case) then the two low order bytes would be reversed - not unlike
standard little-endian machines.

Great fun trying to debug that one! We wound up creating a diagnostic
that decided to check its answers, rather just try a computation...

Needless to say, this company is not in business anymore; they only
actually delivered six machines to customers, and only one of them
used it successfully for any length of time.


Tue, 23 Jan 2001 03:00:00 GMT  
 [ 1 post ] 

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