Browse Prior Art Database

Computer State Machine Implementation of Subsystem Control Block Move Mode Logic Pseudo Code

IP.com Disclosure Number: IPCOM000110248D
Original Publication Date: 1992-Nov-01
Included in the Prior Art Database: 2005-Mar-25
Document File: 2 page(s) / 80K

Publishing Venue

IBM

Related People

Ward, JP: AUTHOR

Abstract

Described is an architectural implementation to provide subsystem control block (SCB) bus master support in a non processor based hardware state machine, as used with personal computer (PC) systems equipped with a Micro Channel* (MC) bus.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 65% of the total text.

Computer State Machine Implementation of Subsystem Control Block Move Mode Logic Pseudo Code

       Described is an architectural implementation to provide
subsystem control block (SCB) bus master support in a non processor
based hardware state machine, as used with personal computer (PC)
systems equipped with a Micro Channel* (MC) bus.

      The state machine is designed to enhance system performance by
relieving the processor from executing lengthy input/output (I/O)
cycles.  The design involves the move mode implementation of SCB
architecture which calls for a number of sequential
read/write/compare operations in the enqueuing and dequeuing of
control elements.  The concept described herein implements this logic
pseudo-code in a hardware state machine format.

      The following is an example of the SCB logic pseudo-code:
        - Main Line Flow for single element ENQUEUE
           Line
             1  IF (EF>SSE)or (EF=SSE and (ew=sdw))
             2     THEN set EF=top
             3     ELSE set EF=SSE
             4  IF X <or= EF-SF
             5     THEN...
             .      .
             .      .
             .      .

      The figure shows the state machine flow that supports the SCB
move mode operations.  Each block shown describes a sequential state
that is executed by the SCB support hardware...