Abstract: A system and associated method for dynamically allocating vertex data to a plurality of geometry accelerators in a computer graphics system based upon the relative current capability of the geometry accelerators to process the data. This efficient distribution of vertex data substantially reduces the amount of time individual geometry accelerators remain idle, thereby increasing both the efficiency of each geometry accelerator as well as the overall parallel processing of vertex data. This selective utilization of geometry accelerators thereby results in a significant increase in the throughput performance of the computer graphics system. A computer graphics system in accordance with the present invention comprises a plurality of geometry accelerators and a distributor connected through two unidirectional buses that transmit data in opposite directions. The geometry accelerators are connected, through appropriate interfacing hardware, directly to an input bus.

Abstract: A graphics system enables an automatic choice between existing host rendering programs, existing hardware acceleration methods, and enhanced software acceleration programs for rendering graphic primitives. The graphics system accesses the speed and accuracy characterizations of a hardware accelerator attached to the system. Then, for each graphics primitive available from the enhanced software acceleration programs, the graphics system invention compares the speed and accuracy of the attached hardware accelerator with that of the enhanced software acceleration programs. The graphics system invention then selects which graphics primitives should be rendered by the enhanced software acceleration programs and which graphics primitives should be rendered by the attached hardware accelerator.

Abstract: A computer system having a core logic chipset that functions as a bridge between an Accelerated Graphics Port ("AGP") bus device such as a graphics controller, and a host processor and computer system memory wherein a Graphics Address Remapping Table ("GART table") is used by the core logic chipset to remap virtual memory addresses used by the AGP graphics controller into physical memory addresses that reside in the computer system memory. The GART table enables the AGP graphics controller to work in contiguous virtual memory address space, but actually use non-contiguous blocks or pages of physical system memory to store textures, command lists and the like. The GART table is made up of a plurality of entries, each entry comprising an address pointer to a base address of a page of graphics data in the computer system physical memory, and feature flags that may be used to customize the associated page of graphics data.

Abstract: A computer graphics system for rendering graphics primitives based upon primitive data received from a host computer through a graphics interface. The primitive data may include vertex state and property state values. The computer graphics system includes a plurality of geometry accelerators configured to process the primitive data to render graphics primitives. The graphics primitives are rendered from one or more vertex states in accordance with the property states currently maintained in the rendering geometry accelerator. A distributor divides the primitive data into chunks of primitive data and distributes each of the primitive data chunks to a current geometry accelerator recipient. In one aspect of the invention, the distributor includes a state controller interposed between the host computer and said plurality of geometry accelerators.

Abstract: The present invention relates to a three-dimensional graphic display apparatus for performing a hidden surface removal and color blending, and particularly to a configuration of a special purpose memory for graphics and a configuration of a graphic display apparatus using the special purpose memory. The special purpose memory for graphics according to the present invention comprises a memory cell for holding intensity information (RGB) and window information about each pixel therein, an XY coordinate converter for converting XY coordinates of a pixel to be written to a memory address, an intensity blending processor, and hidden-surface removal and window comparators, all of which are formed on the same chip.

Abstract: A computer system having a core logic chipset that functions as a bridge between an Accelerated Graphics Port ("AGP") bus device such as a graphics controller, and a host processor and computer system memory wherein a Graphics Address Remapping Table ("GART table") is used by the core logic chipset to remap virtual memory addresses used by the AGP graphics controller into physical memory addresses that reside in the computer system memory. The GART table enables the AGP graphics controller to work in contiguous virtual memory address space, but actually use non-contiguous blocks or pages of physical system memory to store textures, command lists and the like. Contiguous virtual memory address space must be allocated for the AGP device within the addressable memory space of the computer system, typically 4 gigabytes using 32 bit addressing.

Abstract: A computer system having a core logic chipset that functions as a bridge between an Accelerated Graphics Port ("AGP") bus device such as a graphics controller, and a host processor and computer system memory wherein a Graphics Address Remapping Table ("GART table") is used by the core logic chipset to remap virtual memory addresses used by the AGP graphics controller into physical memory addresses that reside in the computer system memory. The GART table enables the AGP graphics controller to work in contiguous virtual memory address space, but actually use non-contiguous blocks or pages of physical system memory to store textures, command lists and the like. The GART table is made up of a plurality of entries, each entry comprising an address pointer to a base address of a page of graphics data in memory, and feature flags that may be used to customize the associated page.

Abstract: The present invention provides a method and apparatus for processing primitives in a computer graphics display system. The present invention comprises a geometry accelerator for processing polygons to provide two-sided lighting for front and back facing polygons. The geometry accelerator comprises a lighting machine and a memory device in communication with the lighting machine. The geometry accelerator receives command data, vertex data, and parameter data from a central processing unit (CPU) of a computer graphics display system. The vertex data comprises polygon vertex color data, vertex coordinate data and vertex normal data. The parameter data comprises front and back material parameters. The command data comprises information relating to the type of primitive to be processed by the lighting machine.

Abstract: A system and method for performing speculative execution of state machine operation in a graphics accelerator. In accordance with one aspect of the invention, the method includes the step of executing steps in a first state machine that is operating on a graphic primitive. As is known, a graphic primitive is defined by a plurality of vertices. In accordance with the invention, the preferred embodiment receives the coordinate parameters for the second to last primitive vertex. Then it evaluates one or more conditions that indicate whether steps in a second state machine need to be executed, based upon parameters of primitive vertices already received. It then branches to and begins executing steps in another state machine, based upon the tentative conditions, and continuing execution of the steps in the transformation state machine in parallel with the continued execution of the steps in the another state machine.

Abstract: Various character strings are repeatedly displayed on a graphics display. For example, strings such as "file", "edit", "view" and "help" are commonly displayed on nearly every screen. This redundancy of displayed character strings is exploited using a string cache and string caching method. A string cache stores a database of strings along with the rendered forms of the strings. The string cache stores the strings in a rendered form which for particular character strings and attributes and characteristics of the strings. The string cache is stored and accessed local to a graphics accelerator so that a single string request across a system bus activates the display of the entire string, including a display of the selected attributes and characteristics.

Abstract: An innovative method and system of performing multiway branch operations on a microprocessor architecture which supports single instruction multiple data (SIMD) operations is provided. A computer processor includes a branch condition register, a graphic status register, a displacement register, a branch offset register, a program counter register and circuit logic responsive to a multiway branch opcode. Bitwise AND logic coupled to the branch condition register and the graphic status register performs a bitwise logical AND between a mask contained in the branch condition register and multiple comparison results contained in the graphic status register. An output port from bitwise logical AND is coupled to a constant array and selects a set of constant values based on the bitwise logical AND result value.

Abstract: A multiple use core logic chip set is provided in a computer system that may be configured either as a bridge between an accelerated graphics port ("AGP") bus and host and memory buses, as a bridge between a 64 bit additional peripheral component interconnect ("PCI") bus and the host and memory buses, or as a bridge between a primary PCI bus and an additional PCI bus. The function of the multiple use chip set is determined at the time of manufacture of the computer system or in the field whether an AGP bus bridge or an additional 64 bit PCI bus bridge is to be implemented. The multiple use core logic chip set has an arbiter having Request ("REQ") and Grant ("GNT") signal lines for each PCI device utilized on the additional 64 bit PCI bus. Selection of the type of bus bridge (AGP or PCI) in the multiple use core logic chip set may be made by a hardware signal input, or by software during computer system configuration or power on self test ("POST").

Abstract: The present invention provides a method and apparatus for transferring a video image, to be resized, from a host processor to an accelerator chip of a display adapter such that the storage capacity of a memory device in the chip is greatly reduced. The video data is first divided into MxM arrays of data elements. Then, the arrays are transferred one row at a time. Each row is stored before being processed by the chip. Consequently, since these rows are much shorter than the lines of frames of data elements, the storage capacity of the chip's memory device is greatly reduced.

Abstract: A clamping system is designed to clamp floating point values from a geometry accelerator in a computer graphics system. The clamping system includes a register configured to receive the floating point value from a connection from the geometry accelerator in the graphics system. Logic associated with the register is configured to determine when the value is less than or equal to a first threshold value (preferably, 0), greater than or equal to a second threshold value (preferably, 1), and between the first and second threshold values. An output mechanism is controlled by the logic. In the preferred embodiment, the output mechanism is a multiplexer interconnected with a tristate driver.

Abstract: A multiple use core logic chip set is provided in a computer system that may be configured either as a bridge between an accelerated graphics port ("AGP") bus and host and memory buses, as a bridge between a 32 bit additional peripheral component interconnect ("PCI") bus and the host and memory buses, or as a bridge between a primary PCI bus and an additional PCI bus. The function of the multiple use chip set is determined at the time of manufacture of the computer system or in the field whether an AGP bus bridge or an additional 32 bit PCI bus bridge is to be implemented. The multiple use core logic chip set has an arbiter having Request ("REQ") and Grant ("GNT") signal lines for each PCI device utilized on the additional 32 bit PCI bus. Selection of the type of bus bridge (AGP or PCI) in the multiple use core logic chip set may be made by a hardware signal input, software during computer system configuration or power on self test ("POST").

Abstract: The data transferred from a computer to the accelerator are stored in the transfer data storage region together with the transfer flag that indicates the destination of transfer. The transfer data determination unit determines the destination of data transfer from the transfer flag, and the graphic data that do not need to be extended are directly written into the graphic data storage means of the accelerator, and the graphic data that do need to be extended and the control data are written into the shared memory. The graphic data are extended by the graphic data extension processing unit and are written into the graphic data storage unit. The interrupt control unit and the interrupt processing unit work to change over the writing of graphic data into the graphic data storage unit and bring the output from the transfer data determination unit into synchronism with the output from the graphic data extension processing unit.

Abstract: A graphics controller (IMC) which performs pointer-based and/or display list-based video refresh operations that enable screen refresh data to be assembled on a per window basis, thereby greatly increasing the performance of the graphical display. The graphics controller maintains pointers to various buffers in system memory comprising video or graphics display information. The graphics controller manipulates respective object information workspace memory areas corresponding to each object or window, wherein the workspace areas specify data types, color depths, 3D depth values, alpha blending information, screen position, etc. for the respective window or object on the screen. Each workspace area also includes static and dynamic pointers which point to the location in system memory where the pixel data for the respective window or object is stored.

Abstract: A computer graphics system includes a plurality of geometry accelerators for processing vertex data representative of graphics primitives and providing rendering data. The system includes a distributor responsive to a stream of vertex data for distributing to the geometry accelerators chunks of the vertex data for processing by the geometry accelerators to provide chunks of rendering data. The distributor generates an end of chunk bit indicative of the end of each of the chunks of vertex data. The system further includes a concentrator for receiving the chunks of rendering data from each of the geometry accelerators and for combining the chunks of rendering data into a stream of rendering data in response to end of chunk bits. The stream of rendering data and the stream of vertex data represent sequences of graphics primitives having the same order. A rasterizer generates pixel data representative of a graphics display in response to the stream of rendering data.

Abstract: An image rescaling method utilizing a parallel processor is provided. The computer-implemented method includes the steps of loading multiple word components into a processor in one machine instruction, each word component associated with a pixel of an image; rescaling the multiple word components in parallel; and packing the rescaled multiple word components into an image buffer in one machine instruction. Additionally, a second set of multiple word components may be processed concurrently with the processing of a first set of multiple word components.

Abstract: A three-dimensional graphic display apparatus performs hidden surface removal and color blending. Particularly, the graphic display apparatus includes a configuration of a special purpose memory for graphics, thereby forming a configuration of a graphic display apparatus using the special purpose memory. The special purpose memory for graphics includes a memory cell holding intensity information (RGB) and window information about each pixel, an XY coordinate converter converting XY coordinates of a pixel to be written to a memory address, an intensity blending processor, and hidden-surface removal and window comparators, all of which are formed on the same chip.

Abstract: Methods and apparatus for generating image data are provided. A memory and a data processor are coupled with a system bus. In certain embodiments a data expanding apparatus is also coupled to the system bus and compressed data are transferred to the data expanding apparatus via the system bus and decompressed data are transferred therefrom to the memory without passing the compressed data through the data processor. Also in certain embodiments, an image data generation command string is transferred from the memory to an image data generation device via the system bus without passing the image data generation command string through the data processor.

Abstract: An improved sound generation and display control apparatus for a personal digital assistant capable of improving the system thereof and a transmission performance for various kinds of display apparatuses and capable of editing an externally supplied video source and providing an overlay function, which includes a central processing unit for controlling the entire system so as to display stored data and to generate sound; a graphic and sound co-processor for processing graphic and sound data in accordance with a control of the central processing unit; a memory for storing the graphic and sound data processed by the graphic and sound co-processor and for storing system data; a direct memory access (DMA) controller for accessing the data stored in the memory in accordance with a DMA request; a bus arbitrator and memory controller for arbitrating an allocation of a system bus and for controlling an access to the memory and a refreshment of the memory; a sound generator for receiving the sound data outputted from

Abstract: A graphic apparatus is connected between a host computer and a monitor for admitting video data from a video source to display a picture on the monitor according to commands from the host computer. The graphic apparatus is constructed by a local memory, an admitting unit, a driver unit and a drawing tool. The local memory is provided separately from the host computer, and is functionally divided into a video memory area for storing video data including those representing a graphic pattern and a frame memory area for storing video data representing a picture to be displayed. The admitting unit operates in response to an admission command from the host computer for admitting video data from the video source and reserving the admitted video data in the video memory area. The driver unit operates in response to a drive command from the host computer for transferring the video data from the frame memory area to the monitor so as to display the picture.

Abstract: A computer system having a pixel processing unit with multiple subprocessors receives positional data defining graphical objects from the CPU and writes pixel data into the image memory, and a display driver produces an image which partially includes the rendered pixels. The pixel processor is used to access patches of multiple contiguous pixels at a time, and process them in parallel. The patches used are defined, within the overall geometry of the image, to have aligned corners. The unit is also connected to receive synchronization signals from the display driver, conditioned on whether the current line being accessed by the driver is within a specified range of lines in the image space.

Abstract: A pixel engine pipeline (including a "front-end" and a "back-end") communicates pixel information between a graphics processor, a pixel engine, a data cache, and system memory. The "front-end" (for reading requested data) includes a command queue for receiving graphics instructions from a graphics processor. Read requests in the command queue are stored in a read request queue. Extraction instructions corresponding to at least a portion of the read request are stored in an attribute queue. Control logic determines whether the requested data is located in a data cache. The read request is stored in a load request queue and the requested data is retrieved from system memory into a load data queue, if the requested data is not in the data cache. The control logic stores the requested data into a read data queue. The requested data is provided to a stage of the pixel engine from the read data queue in accordance with the extraction instructions.

Abstract: A floating point processor for a 3-D graphics accelerator which includes improved performance over prior art designs. The floating point processor includes three specialized engines or function units which streamline floating point operations and which provide improved performance over prior systems. In the preferred embodiment, the floating point processor comprises a floating point core (F-core), a lighting core (L-Core), and a set-up core (S-core). Computations for triangles and vectors are split over the three function units for improved efficiency. The F-core processor receives geometry primitive data and performs floating point operations on the received geometry data. The L-Core processor comprises a fixed point computational unit for performing lighting computations. The set-up core comprises a fixed point computational unit for performing set-up calculations for geometric primitives.

Abstract: A processor having two separate and relatively independent memory controllers to achieve a dual interface architecture. A first memory controller is coupled to the host interface for retrieving data and instructions and a second memory controller is coupled to an independent local bus for interfacing with a frame buffer memory. A depth buffer may also be coupled to the local bus if desired. Address multiplexor logic is preferably included to allow either memory controller to address either external bus. Multiplexor and buffer logic is also preferably included to allow data transfer in either direction. Preferably, the processor is a graphics processor and both memory controllers are programmable for different addressing formats, such as linear and X/Y in the preferred embodiment. In this manner, data is transferred from host to local memories, and vice versa, in any desired format without delays due to memory controller reconfiguration.