Browse Prior Art Database

Program Supervisor

IP.com Disclosure Number: IPCOM000097545D
Original Publication Date: 1961-Feb-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 34K

Publishing Venue

IBM

Related People

Maling, K: AUTHOR

Abstract

Computer program debugging is expedited by maintaining a count of instructions and by utilizing a supervisory program to interpret program errors in the light of the instruction count.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 67% of the total text.

Page 1 of 2

Program Supervisor

Computer program debugging is expedited by maintaining a count of instructions and by utilizing a supervisory program to interpret program errors in the light of the instruction count.

The Instruction Count Register is preset to an initial count according to the supervisory program. The instruction count is decremented 1 upon each change of the instruction address in the Instruction Address Register. When the count goes to zero, control is transferred to the supervisory program.

The supervisory program uses the instruction count in various checks such as: 1. Loop Length. The supervisory program

includes this information:

(a) Longest intentional loop length.

(b) Largest number of iterations in any one loop.

At regular time intervals during execution of a program, the supervisory program initiates a loop-checking sequence. The initial setting of the Instruction Address Register is compared with subsequent settings at one-instruction intervals until the maximum loop length is exceeded (program bug) or the initial instruction address setting is recognized. If a loop is recognized, the number of iterations is compared against the largest number of iterations allowed until this is exceeded (program bug) or loop exit is performed.

2. Single Cycle. By setting the count at +1 and transferring control to the supervisory program on zero count, the problem program is traced one instruction at a time.

3. Synthesis of Pre-Error Circumstances. Should a first...