Compaq Computer Corporation, Inc.

Hewlett-packard Development Company, L.p.

Compag Computer Corporation

Eagle Broadband, Inc.

Giang H Dao

John J Watters

Thanh Thien Tran

Michael P Moriarty

Randolph W Spurlock

Jonathan E Hayden

Harold A Vang

An electronic system that includes control logic that causes input and output ports to be disabled during the interruption windows of the initialization process, and subsequently to be selectively disabled or enabled after completion of the initialization process. The input and output ports are disabled during initialization of the electronic system to prevent interruption of the initialization process by the user. The input and output ports are disabled or enabled, after completion of the initialization process, to control access to content stored on, or made available by, the electronic system.

Input/output device disable control for PC-based consumer electronics device

A digital television/local bus interface logic supports handling of digital television (DTV) data with non-tearing. The interface logic provides a dual frame buffer DTV architecture in which a pair of DTV/local bus frame buffers alternate functions: one frame buffer stores incoming DTV data and the other frame buffer stores the outgoing DTV data. When a refresh of a display device reaches a programmed position of the display device, the interface logic determines which frame buffer is being updated by the incoming DTV data. The outgoing DTV data is then read from an opposite frame buffer and transmitted to the display device. The interface logic receives a horizontal sync signal and a vertical sync signal from the graphics controller for monitoring refresh of the display device. The interface logic also provides an architecture for transferring decoded DTV data over a local bus to the graphics controller.

Method and apparatus for transmitting digital television data

A graphics controller for use in a computer system includes a run slice line draw engine to generate a line as a plurality of slices. The run slice line draw engine calculates the length of the slices responsive to line definition parameters, such as the coordinates of the two line endpoints. Groups of like-sized slices can be determined to decrease the computations necessary to compute the size of each slice. The slices can be either drawn to the display through the frame buffer or used as endpoints for other lines to be generated. To increase the speed of operation, while parameters requiring a division are being calculated, the partial quotient is being used to generate partial slices. Clipped lines can be generated in part using normal Bresenham techniques for partial slices and using the run slice techniques for the full slices entirely within a window. The run slice line draw engine can be used for a plurality of functions other than simple line draws, such as polygon fills, stretching, shrinking or shading.

Method and apparatus to draw line slices during calculation

A graphics controller for use in a computer system includes a run slice line draw engine to generate a line as a plurality of slices. The run slice line draw engine calculates the length of the slices responsive to line definition parameters, such as the coordinates of the two line endpoints. Groups of like-sized slices can be determined to decrease the computations necessary to compute the size of each slice. The slices can be either dram to the display through the frame buffer or used as endpoints for other lines to be generated. To increase the speed of operation, while parameters requiring a division are being calculated, the partial quotient is being used to generate partial slices. Clipped lines can be generated in part using normal Bresenham techniques for partial slices and using the run slice techniques for the full slices entirely within a window. The run slice line draw engine can be used for a plurality of functions other than simple line draws, such as polygon fills, stretching, shrinking or shading.

Run slice line draw engine with enhanced line configurations

A graphics controller for use in a computer system includes a run slice line draw engine to generate a line as a plurality of slices. The run slice line draw engine can perform non-linear scaling and shading of lines in accordance with a parametric equation by approximating the parametric equation as a polyline with a plurality of linear segments. The polyline approximation can be generated using information concerning each derivative of the parametric equation. Each linear segment of the polyline includes a plurality of slices generated by the run slice line draw engine. By approximating the polyline as a plurality of linear segments, non-linear scaling and/or shading by the run slice line draw engine can be performed without complex mathematical computations.

Run slice line draw engine with non-linear scaling capabilities

Run slice line draw engine with enhanced processing capabilites

Run slice line draw engine with stretching capabilities

A video controller uses memory-mapping to address registers in the video controller to enhance speed of the computer system. The memory-map registers may be mapped to a high address area located within the address space of the frame buffer or to a low address area below one megabyte.

Memory-mapped video control registers

Run slice line draw engine with shading capabilities

Run slice line draw engine with non-linear shading capabilities

A graphics controller for use in a computer system includes a run slice line draw engine to generate a line as a plurality of slices. The run slice line draw engine calculates the length of the slices responsive to line definition parameters, such as the coordinates of the two line endpoints. Groups of like-sized slices can be determined to decrease the computations necessary to compute the size of each slice. The slices can be either drawn to the display through the frame buffer or used as endpoints for other lines to be generated. To increase the speed of operation, while parameters requiring a division are being calculated, the partial quotient is being used to generate partial slices. Clipped lines can be generated in part using normal Bresenham techniques for partial slices and using the run slice techniques for the full slices entirely within a window. The run slice line draw engine can be used for a plurality of functions other than simple line draws, such as polygon fills, stretching, shrinking or shading. Non-linear scaling and nonlinear shading can be performed in accordance with a parametric equation by approximating the parametric equation as a polyline having a plurality of linear segments. Scaling and/or shading can be performed responsive to the linear segments of the polyline, thereby avoiding complex mathematical computation. A polyline approximating a parametric equation of degree n may also be displayed on a video display using information generated for n-1 derivatives of the parametric equation.

Method and apparatus for displaying a parametric curve on a video display

Run slice line draw engine with enhanced clipping techniques

A method and apparatus is provided for efficiently determining scissored line segments within a window, without the use of long division calculations. Edges are examined to determine whether an intersection exists between the line and the edge. If so, endpoints of the edge are iteratively halved to find the point of intersection. A Bresenham error term for the point of intersection may be easily determined once the point of intersection is found.

Method and apparatus for efficiently determining line segments within a

A line draw engine for generating Bresenham and DDA lines includes an adder, circuitry for generating a control sign indicative of whether a Bresenham or a DDA line is desired, circuitry for selectively inverting an output of the adder responsive to the control signal and Bresenham line draw logic coupled to the adder and the control signal for drawing a next point responsive to the output of the inverting circuitry.

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Houston, TX, United States of America

Giang H Dao