Method and apparatus for accessing unaligned data

Details Method and apparatus for accessing unaligned data Method and apparatus for accessing unaligned data

1999-12-22

2002-09-10

Hudspeth, David (Department: 2654)

Electrical computers and digital processing systems: memory

Address formation

Slip control, misaligning, boundary alignment

C711S213000, C711S220000

Reexamination Certificate

active

06449706

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates computers, and, in particular, accessing unaligned data from a memory device.
BACKGROUND OF THE INVENTION
Memory lines are typically divided into cache line boundaries. In the example illustrated in
FIG. 1
, the cache lines are sub-divided into 8-byte boundaries. If a memory address corresponds to a boundary line, the memory address is considered an “aligned access”. If a memory address does not corresponds to a boundary line it is considered an unaligned access, and can typically take 2.5 times longer to access.
The number of unaligned access is typically high in computer applications. As a result, the memory latency associated with the unaligned accesses creates a bottleneck effect that limits the performance of image/video processing and other applications.
SUMMARY OF THE INVENTION
The present invention provides a method and apparatus for accessing data from a memory. The method includes masking off a portion of a first memory address, and accessing a first unit of data corresponding to the first memory address. In addition, the method includes adding a predetermined offset to the first memory address to generate a second memory address, and accessing a second unit of data corresponding to the second memory address. Thereafter, a section of the first unit of data is shifted off, and a separate section from the second unit of data is shifted off. Next, the first unit of data and the second unit of data are joined.


REFERENCES:
patent: 4569016 (1986-02-01), Hao et al.
patent: 5249280 (1993-09-01), Nash et al.
patent: 5386531 (1995-01-01), Blaner et al.
patent: 5502683 (1996-03-01), Marchioro
patent: 5715421 (1998-02-01), Akiyama et al.
patent: 5900023 (1999-05-01), Pase
patent: 5931945 (1999-08-01), Yung et al.
patent: 5940870 (1999-08-01), Chi et al.
patent: 5995746 (1999-11-01), Sites et al.
patent: 6108745 (2000-08-01), Gupta et al.
patent: 6128639 (2000-10-01), Pase
patent: 6167509 (2000-12-01), Sites et al.

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