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Unified Hardware Event Definition and Measuring Scheme

IP.com Disclosure Number: IPCOM000117530D
Original Publication Date: 1996-Mar-01
Included in the Prior Art Database: 2005-Mar-31
Document File: 2 page(s) / 85K

Publishing Venue

IBM

Related People

Carter, AM: AUTHOR [+3]

Abstract

The definition of a hardware event is the existence of a particular state of a hardware entity.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Unified Hardware Event Definition and Measuring Scheme

      The definition of a hardware event is the existence of a
particular state of a hardware entity.

      An event as used here is defined as a hardware signal or group
of signals changing to some other state, either active or inactive,
from what it was previously.  Examples include the following: a
floating point  add instruction occurring on the instruction unit to
floating point unit  interface bus, an external interrupt, an L1
cache hit.

      When events are defined at some level of the design hierarchy,
these events inherently carry along the signal name at this level.
When a macro is dropped into another layer of hierarchy, all signal
names change and thus, the event definition must change.

      Events can be defined from other events.

      Hardware events, in the past, were defined and measured
haphazardly.  They were never integrated or inherently part of the
simulation environment.  There was never a uniform method of defining
and measuring these events.

      Moreover, events defined at one level of the design were not
carried forward to other levels due to hierarchical signal name
changes.  They had to be redefined at the new level of hierarchy.

      To define an adequate set of events was very time consuming:
to make sure the signal names associated with the events were
correct, that there were no duplicate event names, and that there was
enough storage area for the database that was created when the events
did occur.

      Hardware events are defined and coded as part of the lowest
level simulation environment and carried up the design hierarchy.
The various pieces of this environment use hardware events to
communicate with each other and with the outside world.  Therefore,
this environment depends on these events being defined adequately and
correctly.

The following describes solutions to the problems:

      To solve the problem of signal name changes due to adding more
hierarchy to the design model, the events are defined with a prefix
which is resolved at model build time from the model net name file.

      To solve the problem of signal name changes due to design
changes, all signal names which make up events are placed in an...