Browse Prior Art Database

Variable Length Chain Linked Character List Control

IP.com Disclosure Number: IPCOM000051670D
Original Publication Date: 1981-Feb-01
Included in the Prior Art Database: 2005-Feb-10
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Yu, WC: AUTHOR

Abstract

The invention relates to a variable length chain linked list driven transducer and, more particularly, to a method for terminating an infinite transducer loop operating with respect to the list. The method steps comprise: (1) embedding a termination flag as the pointer associated with a last list element, as it is written into a memory device accessed by the transducer, and (2) inhibiting further processing of the list after detection of the associated pointer.

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Variable Length Chain Linked Character List Control

The invention relates to a variable length chain linked list driven transducer and, more particularly, to a method for terminating an infinite transducer loop operating with respect to the list. The method steps comprise: (1) embedding a termination flag as the pointer associated with a last list element, as it is written into a memory device accessed by the transducer, and (2) inhibiting further processing of the list after detection of the associated pointer.

The embedding of a flag to terminate a variable length list is to be found in communication protocols over highly serialized point-to-point links. It has also found application in each composing printer where the character generating mechanism identifies the last character to be extracted from a chain linked list of characters in the Y coordinate direction under circumstances where variable sized printing and spacing obviates the use of a parameter with the last character.

The above-referenced method may be implemented in such a page composing printer within an apparatus comprising a writable control store including microcode and chain linked lists of characters and a scan table for each page to be printed; a microprocessor for accessing and interpreting the microcode; and a character generator.

Each element in a linked list has associated with it a branching address for the next element. The branching address requires a microprocessor to fetch the conten...