Compaq Computer Corporation, Inc.

Randolph W Spurlock

Giang H Dao

John J Watters

A computer system and method of operating the same to setup a graphics display driver and device are disclosed. The disk storage of the computer system contains a monitor file that specifies various video modes operable by a number of monitor types and models, and also contains a mode file that specifies the video modes operable by a number of graphics controllers. The mode file also contains the video parameters for each of the available video modes. During a setup routine, the computer system determines the monitor and graphics controller that are installed, and for each available driver program, selects a video mode compatible with each; if more than one video mode is compatible, the computer system may select the best video mode. Upon selection of the video mode, and upon installation of the driver, the computer system reads the video parameters from the mode file for the selected mode, such video parameters stored in an interpretive language, and executes the program in order to program the graphics controller according to the video parameters. This arrangement eliminates the need to maintain the video parameters in the driver executable, and thus facilitates configuration and maintenance of the computer system.

File-based video display mode setup

A video driver in a computer system is used to map a large video frame buffer into the logical address space above physical memory while the computer system is operating in WINDOWS STANDARD mode. The requirements of the necessary address space for the frame buffer (i.e., the size of the frame buffer), and the size of physical memory are determined. If there is sufficient address space above physical memory in which to map the frame buffer, the video driver attempts to map the frame buffer there in that address space. The desired physical and linear addresses for the frame buffer are determined. If the video driver detects that MICROSOFT WINDOWS is operating in standard mode, it searches memory to find the page directory that MICROSOFT WINDOWS created. Once the page directory is found, the driver creates a new page table to map the frame buffer into the desired linear address range and adds a new entry to the existing page directory to point to the new page table.

Method and a computer system for allocating and mapping frame buffers

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

A method and apparatus relating to video systems are disclosed. The method automatically selects an appropriate video system driver based on the current video system configuration. In one embodiment, an intermediate video driver is loaded and perceived by the operating environment as the sole video driver. The intermediate video driver receives commands issued to the system video driver and communicates those commands to the selected appropriate configuration-specific video driver.

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Tomball, TX, United States of America

Randolph W Spurlock