Browse Prior Art Database

Real Time Load Management in a Microprocessor

IP.com Disclosure Number: IPCOM000108078D
Original Publication Date: 1992-Apr-01
Included in the Prior Art Database: 2005-Mar-22
Document File: 2 page(s) / 67K

Publishing Venue

IBM

Related People

Daygar, DA: AUTHOR

Abstract

A program-controlled counter is utilized to track the execution time of a program. The program, which may have various execution paths, can limit its own execution time to a specified maximum without having to depend on worst-case calculations.

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

Real Time Load Management in a Microprocessor

       A program-controlled counter is utilized to track the
execution time of a program.  The program, which may have various
execution paths, can limit its own execution time to a specified
maximum without having to depend on worst-case calculations.

      The counter is typically implemented in register space, or
other fast memory space.  At the entry point to the program,
typically, an interrupt entry point, the counter is initialized to a
value representative of the maximum allowable execution time
specified for the program.

      Each significant execution path in the program contains an
instruction to decrement the counter by an amount representative of
the execution time of that path.  At each decision point in the
program, where program execution can be suspended, the counter is
tested.  If the counter is at, or below, some minimum value then the
program will suspend its execution; otherwise, the program will
continue executing.

      In a typical embodiment, the program is used to load hammer
control data into a hardware controller in a band printer.  The
maximum execution time allowed is the time between band
synchronization interrupts.  The execution time depends on the
amount, and type, of control data present.

      The program path that decodes and loads hammer fire data
decrements the counter by one amount, while the path that decodes and
loads hammer reset data decrements the counter by a differe...