Browse Prior Art Database

Dynamically Skipped Code using Jump/Branch Debug Instruction

IP.com Disclosure Number: IPCOM000111966D
Original Publication Date: 1994-Apr-01
Included in the Prior Art Database: 2005-Mar-26
Document File: 2 page(s) / 55K

Publishing Venue

IBM

Related People

Slane, AA: AUTHOR

Abstract

This article describes a method to allow embedded debug/error checking code with minimal path length impact using a new class of processor instructions called jump/branch on debug.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 62% of the total text.

Dynamically Skipped Code using Jump/Branch Debug Instruction

      This article describes a method to allow embedded debug/error
checking code with minimal path length impact using a new class of
processor instructions called jump/branch on debug.

      Typically, object code is optimized and all traces and error
checking are kept to a minimum in ship level code to obtain maximum
performance.  While this achieves the performance goal, it greatly
hinders any debug effort when problems occur since a new bind usually
needs to be built and the problem needs to be recreated with the new
bind.  This is a very time-consuming and wasteful process.  What is
needed is a way to include the debug code in the bind in a seamless
way until needed.  This invention does just that.

A solution to this in the code realm is shown in Fig. 1.

      While the above works, it is very inefficient.  It takes three
instructions including an expensive storage operation to access and
test the static debug variable.  This adversely affects performance
if debug code is to remain in the object code all the time.

      The above problem is solved by adding a new class of processor
instructions called jump/branch on debug.  Instead of the code having
a generic debug variable that gets loaded and tested, the debug state
information now becomes part of the processor state similar to the
condition codes.  This state could be a single bit, an array of bits,
or an integral type of varia...