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Attribute Bit Assignment and Processing for Color Display

IP.com Disclosure Number: IPCOM000045290D
Original Publication Date: 1983-Mar-01
Included in the Prior Art Database: 2005-Feb-06
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Hupcey, JA: AUTHOR [+2]

Abstract

In a color display of the type in which each field in a screen memory is associated with a set of attribute bits which control aspects of the display such as color, a microprocessor routine permits the use of independent attribute bits for each color within a limited set of attribute bits.

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Attribute Bit Assignment and Processing for Color Display

In a color display of the type in which each field in a screen memory is associated with a set of attribute bits which control aspects of the display such as color, a microprocessor routine permits the use of independent attribute bits for each color within a limited set of attribute bits.

A display commonly has a screen memory that holds codes that represent an image of the characters that are to be displayed. The screen memory is accessed sequentially as the raster sweeps the screen, and codes read from the screen memory are used to access a second memory that holds data patterns for characters or graphic symbols on the screen. The screen memory also holds attribute bits that control various functions for a field or a character position of the screen. For example, attribute bits control whether a field is protected against operator entry, whether the image is to be intensified, whether the field can accept a particular data type such as numeric, and the color of the field. These attribute bits are stored with the screen memory codes, and they are interpreted by a microprocessor that controls the display. In order to control a number of functions with only a limited number of attribute bits, some bits may control a combination of attributes, for example, white with protect or blue without protect.

In this system the numeric field bit is used as a second color bit. With two color bits, the system can use a...