Apparatus using memory control tables related to video graphics

Abstract

Apparatus for processing mixed video and graphic signals for display on a television receiver includes a Graphics Memory and a Memory Controller and Sprite State Machine. The Graphics Memory includes a Sprite List table, a Sprite Data table, and other optional tables. The Sprite List table lists one or more graphics in a predetermined sequence for display on the television receiver, and stores general information related to the graphics within control words in each listing. The Sprite Data table stores pixel data for horizontal lines of each of the graphics which are accessed by a control word in each of the graphic listings in the Sprite List table. An optional Line Control table contains control words that are accessed via the graphic listing for providing independent controls for each of the horizontal lines obtained from the Sprite Data table to produce predetermined special effects. An optional Span List table is used to determine which of the graphic listings occur on a horizontal line to cause an accessing of only those occurring graphic listings for assembling pixel data for that horizontal line. The Memory Controller and Sprite State Machine accesses the tables of the Graphics Memory in a predetermined sequence in order to assemble and display each of the graphics and their special effects at predetermined locations in the horizontal lines on a screen of the television receiver. The Memory Controller and Sprite State Machine also uses field enable controls from the Sprite List Table for assembling one graphic on lines of a first filed and a second graphic on lines of a second field.