Browse Prior Art Database

Source Identification Register for Personal Computers

IP.com Disclosure Number: IPCOM000110882D
Original Publication Date: 1994-Jan-01
Included in the Prior Art Database: 2005-Mar-26
Document File: 2 page(s) / 86K

Publishing Venue

IBM

Related People

Farrell, JK: AUTHOR [+9]

Abstract

Described is an architectural implementation to provide a Source Identification Register (SIR) for personal computers equipped with a Micro Channel* (MC). The implementation is designed to improve the signalling operations of Subsystem Control Block (SCB) Move Mode architecture. This is done by using a register to identify the source of a signal as well as to distinguish between a data transfer signal and a control information signal.

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Source Identification Register for Personal Computers

      Described is an architectural implementation to provide a
Source Identification Register (SIR) for personal computers equipped
with a Micro Channel* (MC).  The implementation is designed to
improve the signalling operations of Subsystem Control Block (SCB)
Move Mode architecture.  This is done by using a register to identify
the source of a signal as well as to distinguish between a data
transfer signal and a control information signal.

      In prior art, the SCB Move Mode architecture defined a single
value ('D0'x) to be written to the Attention Port (AP) along with
interrupting status information in shared memory as the signalling
mechanism.  Additionally, mechanisms set individual bits into a
register based on additional values written to the AP.  The concept
described herein provides three improvements, as follows:

o   allows the prior-art architecture to be extended in an optional
    and compatible manner so as to provide a performance improvement
    in the servicing of interrupts that result from an SCB unit being
    signalled from another unit,

o   allows the prior-art architecture to be extended in the
    signalling area by defining a variable number of signal sources
    that can be identified concurrently in the hardware interface,
    and

o   allows these variable signal sources to be associated with one of
    two interrupts to the local bus, dependent on the bit position
    set in the SIR.

      The concept is not part of the SCB Move Mode architecture
extensions that are part of the addition of the SIR function, but is
a compatible extension to them.  The identification of the signalling
source is primarily of interest when using the SCB Move Mode
architecture.  The SIR is used to provide the interrupting source
information to the code that is operating on the adapter by means of
unique interrupts to the local processor.  In addition to providing
an indication of the signal source, the SIR is divided into two
sections which then allows the signals associated with data movement
to be separated from the signals associated with control information.

      Bits in the SIR are only set when accessed indirectly through
...