Abstract: A computer implemented method for processing instructions in a multiprocessing apparatus comprises obtaining a first instruction of a first process; decoding the first instruction to detect a continuation indicator associated with the first instruction; determining whether or not to enforce the continuation indicator; and when it is determined to enforce the continuation indicator: continuing to execute the first process until completion of the first instruction and at least a next sequential second instruction of the first process. The continuation may temporarily suppress a normal eviction process based on a fairness algorithm, for example.

Abstract: When performing a texture sampling operation that uses the results of plural texture filtering operations to provide an overall output sampled texture value in a graphics processing system, it is determined whether a texture filtering operation in the set of plural texture filtering operations that are to be performed to provide the overall output sampled texture value can be at least partially merged with another texture filtering operation in the set of texture filtering operations. If so a merged texture filtering operation is performed for the two texture filtering operations, with the result of the merged texture filtering operation being used when providing the overall output sampled texture value.

Abstract: When performing texture processing operations in a graphics processing system, for a texture processing operation that requires M input texture data elements from an array of texture data elements, each of the M texture data elements is selected from a different set of texture data elements having a different set of positions within the texture data array. The texture processing operation is then performed using the M texture data elements.

Abstract: Disclosed is a data processing system comprising a data processor and a cache that is operable to transfer data from memory to the data processor. The data processor is operable to use data of a type that when transferred to the cache can comprise multiple component values. The data processor is however operable to store within a cache line of the cache a subset of less than all of the component values for a multicomponent data element. The cache is configured to further store in association with each cache line an indication of which data element component values are stored in the cache line so that cache lookups can be performed using the indications of which data element component values are stored in which cache lines.

Abstract: A method of operating a graphics processor when rendering a frame representing a view of a scene using a ray tracing process in which part of the processing for a ray tracing operation is offloaded to a texture mapper unit of the graphics processor. Thus, when the graphics processor's execution unit is executing a program to perform a ray tracing operation the execution unit is able to message the texture mapper unit to perform one or more processing operations for the ray tracing operation. This operation can be triggered by including an appropriate instruction to message the texture mapper unit within the ray tracing program.

Abstract: There is disclosed a method of storing an encoded block of data in memory comprising encoding a block of data elements and determining a memory location (26) at which the encoded block of data is to be stored. The memory location (26) at which the encoded block of data is stored is then indicated in a header (406) for the encoded block of data by including in the header a memory address value (407) together with a modifier value (500) representing a modifier that is to be applied to the memory address value (407) when determining the memory location (26). When the encoded block of data is to be retrieved, the header (406) is read and processed to determine the memory location (26).

Abstract: A texture cache comprises at least two banks of cache storage to cache texels for processing in texture mapping operations. Access to the cached texels corresponding to a given chunk of texels of a given texture image is controlled according to a selected bank mapping selected from two or more bank mappings supported by the texture cache access control circuitry. Each bank mapping corresponds to a different mapping of the respective texels within the given chunk to the banks of cache storage. In at least one operating mode, the selected bank mapping is selected for the given chunk of texels of the given texture image depending on: at least one of first/second chunk position coordinates associated with the given chunk of texels; and at least one further texture attribute associated with the given texture image.

Abstract: A texture cache comprises at least two banks of cache storage to cache texels for processing in texture mapping operations. Access to the cached texels corresponding to a given chunk of texels of a given texture image is controlled according to a selected bank mapping selected from two or more bank mappings supported by the texture cache access control circuitry. Each bank mapping corresponds to a different mapping of the respective texels within the given chunk to the banks of cache storage. In at least one operating mode, the selected bank mapping is selected for the given chunk of texels of the given texture image depending on: at least one of first/second chunk position coordinates associated with the given chunk of texels; and at least one further texture attribute associated with the given texture image.

Abstract: A method of operating a cache system is disclosed. Information indicating a link between associated header and payload cache entries is maintained. The link information may be used to reduce cache coherency traffic.

Abstract: When performing anisotropic filtering when sampling a texture to provide an output sampled texture value for use when rendering an output in a graphics processing system, a number of positions for which to sample the texture along an anisotropy direction along which samples will be taken in the texture is determined by determining the square root of the coefficient F for an ellipse having the form Ax2+Bxy+Cy2=F corresponding to the projection of the sampling point for which the texture is being sampled onto the surface to which the texture is to be applied, and using the determined square root of the ellipse coefficient F to determine the number of positions for which samples should be taken along the anisotropy direction in the texture.

Abstract: When performing anisotropic filtering when sampling a texture to provide an output sampled texture value for use when rendering an output in a graphics processing system, an anisotropy direction along which to take samples in the texture is determined by determining X and Y components of a vector of arbitrary length corresponding to the direction of the major axis of an assumed elliptical projection of the sampling point for which the texture is being sampled onto the surface to which the texture is being applied, and then normalising the determined X and Y vector components to provide X and Y components for a unit vector corresponding to the direction of the major axis of the elliptical footprint of the sampling point to be used as the anisotropy direction along which to take samples in the texture.

Abstract: When performing anisotropic filtering when sampling a texture in a graphics processing system, a number of positions for which to sample the texture along an anisotropy direction is determined. When the determined number of positions for which to sample the texture along the anisotropy direction is a non-integer value that exceeds a lower integer value by more than a threshold amount, samples are taken along the anisotropy direction in the texture for a number of positions corresponding to the next higher multiple of 2 to the determined non-integer number of positions to be sampled. When the determined number of positions for which to sample the texture along the anisotropy direction does not exceed the lower integer value by at least the threshold amount, samples are taken along the anisotropy direction in the texture for a number of positions corresponding to the lower integer value.

Abstract: A method of operating a graphics processor when rendering a frame representing a view of a scene using a ray tracing process in which part of the processing for a ray tracing operation is offloaded to a texture mapper unit of the graphics processor. Thus, when the graphics processor's execution unit is executing a program to perform a ray tracing operation the execution unit is able to message the texture mapper unit to perform one or more processing operations for the ray tracing operation. This operation can be triggered by including an appropriate instruction to message the texture mapper unit within the ray tracing program.

Abstract: There is disclosed a method of storing an encoded block of data in memory comprising encoding a block of data elements and determining a memory location (26) at which the encoded block of data is to be stored. The memory location (26) at which the encoded block of data is stored is then indicated in a header (406) for the encoded block of data by including in the header a memory address value (407) together with a modifier value (500) representing a modifier that is to be applied to the memory address value (407) when determining the memory location (26). When the encoded block of data is to be retrieved, the header (406) is read and processed to determine the memory location (26).

Abstract: When performing anisotropic filtering when sampling a texture to provide an output sampled texture value for use when rendering an output in a graphics processing system, a number of positions for which to sample the texture along an anisotropy direction along which samples will be taken in the texture is determined by determining the square root of the coefficient F for an ellipse having the form Ax2+Bxy+Cy2=F corresponding to the projection of the sampling point for which the texture is being sampled onto the surface to which the texture is to be applied, and using the determined square root of the ellipse coefficient F to determine the number of positions for which samples should be taken along the anisotropy direction in the texture.

Abstract: When performing anisotropic filtering when sampling a texture to provide an output sampled texture value for use when rendering an output in a graphics processing system, an anisotropy direction along which to take samples in the texture is determined by determining X and Y components of a vector of arbitrary length corresponding to the direction of the major axis of an assumed elliptical projection of the sampling point for which the texture is being sampled onto the surface to which the texture is being applied, and then normalising the determined X and Y vector components to provide X and Y components for a unit vector corresponding to the direction of the major axis of the elliptical footprint of the sampling point to be used as the anisotropy direction along which to take samples in the texture.

Abstract: When performing anisotropic filtering when sampling a texture in a graphics processing system, a number of positions for which to sample the texture along an anisotropy direction is determined. When the determined number of positions for which to sample the texture along the anisotropy direction is a non-integer value that exceeds a lower integer value by more than a threshold amount, samples are taken along the anisotropy direction in the texture for a number of positions corresponding to the next higher multiple of 2 to the determined non-integer number of positions to be sampled. When the determined number of positions for which to sample the texture along the anisotropy direction does not exceed the lower integer value by at least the threshold amount, samples are taken along the anisotropy direction in the texture for a number of positions corresponding to the lower integer value.

Abstract: When sampling a pair of mipmaps when performing anisotropic filtering when sampling a texture to provide an output sampled texture value for use when rendering an output in a graphics processing system, more positions along an anisotropy direction are sampled in the more detailed mipmap level than in the less detailed mipmap level. Each position that is sampled may have a single sample taken for it, or may be supersampled.

Abstract: When a data processing operation requires data that is stored in a first cache and the fetching of the data into the first cache is dependent upon data stored in another cache, and an attempt to read the data from the first cache “misses”, the data processing operation is added to a record of data processing operations that have missed in the first cache and the data that is required for the data processing operation is fetched into the first cache by reading the data that is required to fetch the data into the first cache from the another cache and then using that data from the another cache to fetch the required data into the first cache. When the data that is required for the data processing operation has been fetched into the first cache, the data processing operation is performed using the fetched data.

Abstract: When storing an array of data in memory, the data array is divided into a plurality of blocks, and for respective groups of the blocks that the data array has been divided into, a set of data representing the group of blocks that includes: for each block of the group of blocks, a set of data for that block of the group of blocks; and a size indication for each of one or more of the blocks of the group of blocks, the size indication for a block of a group of blocks indicating the size in memory of the set of data for that block of the group included in the stored set of data representing the group of blocks, is stored. A set of header data is also stored separately for each group of blocks of the data array.