US 2003/0154349 A1 · Program-directed cache prefetching for media processors

Abstract

Data are prefetched into a cache from a prefetch region of memory, based on a program instruction reference and on compile-time information that indicates the bounds of the prefetch region, a size of a prefetch block, and a location of the prefetch block. If the program reference address lies with the prefetch region, an offset distance is used to determine the address of the prefetch block. Prefetching is performed either from a continuous one-dimensional prefetch region, or an embedded multi-dimensional prefetch region. The prefetch block address is respectively determined in one dimension or multiple dimensions. Program-directed prefetching is implemented by a media processor or by a separate processing component in communication with the media processor. The primary components include a program-directed prefetch controller, a cache, a function unit, and a memory. Preferably, region registers store the compile-time information, and the prefetched data are stored in a cache prefetch buffer.

Claims31

Dependent claims

A method for prefetching data stored in a memory, comprising the steps of:

(a) providing a reference address associated with a machine instruction that is executable to carryout a function other than prefetching the data;
(b) determining that the reference address indicates a location within a prefetch region of the memory, said prefetch region being defined by compile-time information associated with a set of machine instructions for processing the data;
(c) determining an address of a prefetch block of the data within the prefetch region as a function of the reference address and the compile-time information;
and
(d) prefetching the prefetch block of the data from the prefetch region of the memory before the prefetch block of the data are required for processing in accord with the set of machine instructions.

2 more elements

A system for program-directed prefetching of data for use by a media processor, comprising:

(a) a memory that stores data accessible by the media processor, said memory including a cache in which portions of the data are temporarily stored and are more rapidly accessed by the media processor for processing than the data stored in other portions of the memory;
and
(b) a program-directed prefetch (PDP) controller in communication with the cache, said PDP controller providing the cache with compile-time information that defines a prefetch region of the memory and indicates prefetch data to be prefetched from the prefetch region of the memory in response to a program instruction that is included to cause the media processor to carryout a function other than prefetching data.

A media processor for prefetching media data stored in a memory to avoid programming a direct memory access function to access the media data, comprising:

(a) a function unit that executes machine instructions;
(b) a cache in communication with the function unit, said cache temporarily storing portions of the media data for use by the function unit in executing the machine instructions;
and
(c) a program-directed prefetch (PDP) controller in communication with the function unit and the cache, said PDP controller storing compile-time information that defines a prefetch region of the memory and defines an offset to a prefetch block of the media data in the memory, said prefetch block of the media data being prefetched from a location in the memory determined as a function of the offset and as a function of a reference address indicated by a machine instruction that is executed by the function unit for a purpose other than prefetching data.

1 more element

Dependencies are inferred from the claim text.

Program-directed cache prefetching for media processors

Life of this patent

Program-directed cache prefetching for media processors

Life of this patent

Abstract

Claims31