Abstract: A method and apparatus for utilizing redundant circuitry on integrated circuits (ICs) that may increase manufacturing yields, while maintaining a predetermined set of interfaces for connection with external circuitry without drastically increasing die area and circuit complexity are provided. In this manner, even though an IC may have defects which would otherwise render it inoperable, embodiments of the present invention allow the defects to be circumscribed or avoided while still maintaining a predetermined set of interfaces, thus providing for an operational circuit. Various embodiments further provide a method for sorting or separating devices based on their level of functionality or performance, which in turn depends on their number of defects and the desired number of interfaces.

Abstract: In a graphics processor, a rendering object and a post-processing object share access to a host processor with a programmable execution core. The rendering object generates fragment data for an image from geometry data. The post-processing object operates to generate a frame of pixel data from the fragment data and to store the pixel data in a frame buffer. In parallel with operations of the host processor, a scanout engine reads pixel data for a previously generated frame and supplies the pixel data to a display device. The scanout engine periodically triggers the host processor to operate the post-processing object to generate the next frame. Timing between the scanout engine and the post-processing object can be controlled such that the next frame to be displayed is ready in a frame buffer when the scanout engine finishes reading a current frame.

Abstract: Stippled lines are drawn by evaluating a distance function for a set of points within the area of a stippled line. The distance function gives a distance value proportional to the distance from a point to the end of the stippled line. Using the point's distance value, a pattern index value defines a correspondence between a point and at least one stipple pattern bit. The value of pattern bits are applied to the points on the stippled line, masking the points such that only a portion of the set of points are displayed or determining intensity values according to the position of the points within the stipple pattern. A distance function may be an edge equation associated with the line end or a segment of a polyline. The distance function can be evaluated for the set of points in any order, allowing portions of a stippled line to be drawn in parallel.

Abstract: Methods, circuits, and apparatus for reducing memory bandwidth used by a graphics processor. Uncompressed tiles are read from a display buffer portion of a graphics memory and received by an encoder. The uncompressed tiles are compressed and written back to the graphics memory. When a tile is needed again before it has been modified, the compressed version is read from memory, uncompressed, and displayed. To reduce the number of unnecessary writes of compressed tiles to memory, a tile is only written to memory if it has remained static for some number of refresh cycles. Also, to prevent a large number of compressed tiles being written to the display buffer in one refresh cycle, the encoder can be throttled after a number of tiles have been written. Validity information can be stored for use by a CRTC. If a tile is updated, the validity information is updated such that invalid compressed data is not read from memory and displayed.

Abstract: A method for delayed frame buffer merging. The method includes accessing a polygon that relates to a group of pixels stored at a memory location, wherein each of the pixels has an existing color. A determination is made as to which of the pixels are covered by the polygon, wherein each pixel includes a plurality of samples. A coverage mask is generated corresponding the samples that are covered by the polygon. The group of pixels is updated by storing the coverage mask and a color of the polygon in the memory location. At a subsequent time, the group of pixels is merged into a frame buffer.

Abstract: Stippled lines are drawn by evaluating a distance function for a set of points within the area of a stippled line. The distance function gives a distance value proportional to the distance from a point to the end of the stippled line. Using the point's distance value, a pattern index value defines a correspondence between a point and at least one stipple pattern bit. The value of pattern bits are applied to the points on the stippled line, masking the points such that only a portion of the set of points are displayed or determining intensity values according to the position of the points within the stipple pattern. A distance function may be an edge equation associated with the line end or a segment of a polyline. The distance function can be evaluated for the set of points in any order, allowing portions of a stippled line to be drawn in parallel.

Abstract: Multiple output buffers are supported in a graphics processor. Each output buffer has a unique identifier and may include data represented in a variety of fixed and floating-point formats (8-bit, 16-bit, 32-bit, 64-bit and higher). A fragment program executed by the graphics processor can access (read or write any of the output buffers. Each of the output buffers may be read from and used to process graphics data by an execution pipeline within the graphics processor. Likewise, each output buffer may be written to by the graphics processor, storing graphics data such as lighting parameters, indices, color, and depth.

Abstract: A system, method and computer program product are provided for performing depth testing and blending operations in a first mode and a second mode. In the first mode, a circuit processes a first number (m) of first pixels per clock cycle, each of the first pixels including both color values and depth values. In the second mode, the circuit processes a second number (n) of second pixels per clock cycle. Each of the second pixels includes the depth values and not the color values. Further, the second number (n) is greater than the first number (m).

Abstract: A multi-mode texture compression algorithm is provided for effective compression and decompression texture data during graphics processing. Initially, a request is sent to memory for compressed texture data. Such compressed texture data is then received from the memory in response to the request. At least one of a plurality of compression algorithms associated with the compressed texture data is subsequently identified. Thereafter, the compressed texture data is decompressed in accordance with the identified compression algorithm.

Abstract: A system, method and computer program product are provided for avoiding reading z-values in a graphics pipeline. Initially, near z-values are stored which are each representative of a near z-value on an object in a region. Such region is defined by a tile and a coverage mask therein. Thereafter, the stored near z-values are compared with far z-values computed for other objects in the region. Such comparison indicates whether an object is visible in the region. Based on the comparison, z-values previously stored for image samples in the region are conditionally read from memory.

Abstract: A system, method and computer program product are provided for avoiding reading z-values in a graphics pipeline. Initially, near z-values are stored which are each representative of a near z-value on an object in a region. Such region is defined by a tile and a coverage mask therein. Thereafter, the stored near z-values are compared with far z-values computed for other objects in the region. Such comparison indicates whether an object is visible in the region. Based on the comparison, z-values previously stored for image samples in the region are conditionally read from memory.