Browse Prior Art Database

Interactive Alter Display Instruction Trace Programming Aid

IP.com Disclosure Number: IPCOM000081795D
Original Publication Date: 1974-Aug-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 5 page(s) / 97K

Publishing Venue

IBM

Related People

Cianciosi, M: AUTHOR [+2]

Abstract

This is a method in a computer system for altering or displaying the contents of either main or control storage using a software approach, while utilizing the I/O facilities of the computer system.

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 41% of the total text.

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Interactive Alter Display Instruction Trace Programming Aid

This is a method in a computer system for altering or displaying the contents of either main or control storage using a software approach, while utilizing the I/O facilities of the computer system.

A programmer, while debugging his programs, uses this method to observe storage data and register data, as it is visually displayed on the system's cathode-ray tube (CRT) or outputted on the systems printer. This gives him the advantage of easily seeing multiple areas of storage and making program corrections immediately, as opposed to taking storage dumps or bit switching data or displaying conditions on a light panel.

I/O devices connected to a computer system, such as CRT/Keyboard, printer and a disk storage drive, are utilized as visual aids, storage facilities and provide input data in support of programming debug.

Even though these devices are operational while an application program is in progress, they are used as a tool to give visual responses and/or recorded (printed) responses to that same program while executing.

This is beneficial to a programmer in that he is able to follow the sequence of instructions as his program is executing. At the same time, he can patch instructions during 'debug' time and have recorded hardcopy of his program as it executes any patches he may have made.

Some of the options a program has available in this feature are:
1. Processor Run Mode with a line of print recording

pertinent system registers, such as the IAR, ARR,

XR1, XR2 and PSR. These registers show their status

after an instruction is executed.
2. An Instruction Step Mode, where a line of print

depicts the system registers, and the display on the

CRT would have in addition to system register

information, storage bytes that are selected from

address switches on the CE Panel or keyed in from

the keyboard. The programmer can also make alterations

to storage data before executing the next instruction.
3. The option of having no printing and just a visual CRT

display of the information described in 2. Altering of

storage data is also permitted.

Another advantage is the ease and convenience in altering macro instructions (system code) or microprograms (control code), by not having to manipulate the control panel rotary switches and push buttons. All data and address selections are made from the system's keyboard.

Not only are the system I/O devices utilized, but the same control microprogram residing in control storage is used in addition to the normal operation of the system. The segment of coding necessary to perform the

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alter/display instruction trace feature, is contained in a transient module of code that is called from the disk and replaces an unused segment of microcode, whose function is not needed when the feature is being utilized.

With the presence of this module in control storage, the system under manual or automatic control is temporarily converted to a prog...