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Hardware Feature for Program Tracing during Execution

IP.com Disclosure Number: IPCOM000076340D
Original Publication Date: 1972-Feb-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Daugan, G: AUTHOR

Abstract

This hardware feature permits the record checking of information at a given point of the execution of a program, and gives back control rapidly to the normal flow of the program. This "on-line processing" is only disturbed at the control speed level and not at operator speed level.

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Hardware Feature for Program Tracing during Execution

This hardware feature permits the record checking of information at a given point of the execution of a program, and gives back control rapidly to the normal flow of the program. This "on-line processing" is only disturbed at the control speed level and not at operator speed level.

When checking has to be made at a given address in a program, the operator selects a special run mode (SAR or IAR stop mode), and enters in data switches the representation of the wanted address, as usual.

During program execution, each address (instruction or storage access) is compared to the given address, by hardware means. Whenever the contents of the register which holds the current address equals the given address, the controller generates a high level interruption which may have priority over all the other interruptions. The program which gets control by the interruption mechanism (Trace program) records the necessary information and according to the function required, compares it to previous or other values, prints it, takes decisions on further analysis and procedures, etc. Then the Trace program gives back control to the program main flow.

The interference in the online processing is limited to the time the Trace program is executed. No extra time is lost for address comparison, either the trace option is active or not.

No extra coding is required in the program main flow to give control to the Trace program. It means tha...