Browse Prior Art Database

Code Distributor

IP.com Disclosure Number: IPCOM000088571D
Original Publication Date: 1977-Jul-01
Included in the Prior Art Database: 2005-Mar-04
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Berger, DA: AUTHOR [+2]

Abstract

A code distributor is used in a stand-alone word processing system or interactive terminal to pass control to any specified control program routine by responding to a code input from a keyboard or other input device, addressing a table at the address specified by the code, and accessing the control program at the address specified by the address bytes contained at the addressed table location. A plurality of tables may be used in the system. For simple control programs, a single table may be sufficient; however, a table may be associated with each stage or subroutine of a complex control program. A register, associated with the distributor, stores the location of the active table.

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Code Distributor

A code distributor is used in a stand-alone word processing system or interactive terminal to pass control to any specified control program routine by responding to a code input from a keyboard or other input device, addressing a table at the address specified by the code, and accessing the control program at the address specified by the address bytes contained at the addressed table location. A plurality of tables may be used in the system. For simple control programs, a single table may be sufficient; however, a table may be associated with each stage or subroutine of a complex control program. A register, associated with the distributor, stores the location of the active table. The tables may be permanently stored in the system with read-only storage, or the table may be loaded into a random-access memory by a particular program. When the code has been processed by the control program, control is returned to the code distributor.

The code distributor concept is an alternative to a test for each individual code input. In this type of time consuming testing, the code is tested and appropriate action is taken according to the code, terminal application, and application stage. Thus, with the code distributor the keyboard or other input device channel time is reduced by minimizing the time from keystroke to terminal application process start because less time is taken to do a table lookup than to perform a test on many types of characters. By centr...