Cirrus Logic Inc.

S3 Incorporated, Inc.

Thuan Thai Hoang

Bradley A May

William W Chu

Rajan N Kapur

A method and apparatus is disclosed for reading display data from the same area in display memory and processing the display data as video pixel data or graphics pixel data depending on the state of at least one tag bit stored with the data. The apparatus receives display data from display memory, separates at least one tag bit from the display data and uses at least one tag bit in a controller to enable processing display data as video pixel data or graphics pixel data in each processing step. Video pixels may be corrected for missing color components with stored value if previous or next pixel in pipeline is graphics. Display memory and display memory bandwidth may be conserved by enabling video pixel data formats and graphics pixel data formats to be stored within the same display memory area.

Controller for processing different pixel data types stored in the same

A graphics interface circuit for connecting a serial output port of a video RAM to a RAMDAC to allow a user selectable color mode to be displayed wherein the selectable color modes allows one of 256, 32K, 64K or 16.7M colors to be displayed at one time. A host microprocessor addresses the video RAM as a linear, unfragmented address space in the selected one of these modes. The invention provides an improved utilization of the video RAM memory space, as well as improved memory bandwidth as compared with prior art techniques. A graphics interface module allows for 8, 16, 24 or 32 bit wide output on the data bus from the interface to a RAMDAC. A display system of the type in which the present invention may be utilized places data generated by a host processor, after processing by a graphic displays processor into a video memory. The display processor constantly updates the video memory based upon the data generated by the host processor. The data in the video memory is transferred to a graphics interface which receives the data from the video memory and passes it to the RAMDAC which converts the digitized data into analog signals capable of being displayed by a display.

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Santa Clara, CA, United States of America

Thuan Thai Hoang