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US6173367B1 Expired / Lapsed US ⏱️ 0.0 years remaining

Method and apparatus for accessing graphics cache memory

Assignee: ATI Technologies ULC
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Filing: 1999-05-19
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Granted: 2001-01-09
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Expires: 2019-05-19
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Abstract

Abstract A method and apparatus for utilizing a data cache in a system with both 2D and 3D graphics applications. In a specific embodiment of the present invention, a mode signal is received by the video system indicating whether a 2D or 3D application is to be used. Depending on the mode signal, either as a unified cache capable of being accessed by two separate data access streams, or two independent caches, each accessed by one data access stream.

Inventors

  • 👤 Milivoje Aleksic
  • 👤 James Yee
  • 👤 Danny H. M Cheng
  • 👤 John DeRoo
  • 👤 Andrew E. Gruber

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-10 01:16
CPC Classifications
G; G06; G06F; G06F12/00; G06F12/02; G06F12/08; G06F12/0802; G06F12/0844; G06F12/0855; G06F12/0857; G06F12/0846; G06F12/0848; G06F12/0875

Claims Analysis

Total Claims: 18
Claim 1
Independent Claim 232 words
A method of accessing a video data cache, the method comprising: receiving a mode indicator, wherein the mode indicator indicates one of a first and second mode of cache operation; during the first mode of cache operation performing the following steps: partitioning a first and second portion of the video cache to be accessible to both a first client and a second client; receiving a first memory access request from the first client and receiving a second memory access request from the second client; accessing a first word of the first portion of the video cache based on the first memory access request; and simultaneously accessing a second word of the first portion of the video cache based on the second memory access request; and during the second mode of cache operation performing the following steps: partitioning the first portion of the video cache to be accessible to a third client and inaccessible to a fourth client; partitioning the second portion of the video cache to be accessible to the fourth client and inaccessible to the third client; receiving a third memory access request from the third client and simultaneously receiving a fourth memory access request from the fourth client; accessing the first portion of the video cache based on the third memory access request; and simultaneously accessing the second portion of the video cache based on the fourth memory access request.
Claim 2
Independent Claim 232 words
A method of accessing a video data cache, the method comprising: receiving a mode indicator, wherein the mode indicator indicates one of a first and second mode of cache operation; during the first mode of cache operation performing the following steps: partitioning a first and second portion of the video cache to be accessible to both a first client and a second client; receiving a first memory access request from the first client and receiving a second memory access request from the second client; accessing a first word of the first portion of the video cache based on the first memory access request; and simultaneously accessing a second word of the first portion of the video cache based on the second memory access request; and during the second mode of cache operation performing the following steps: partitioning the first portion of the video cache to be accessible to a third client and inaccessible to a fourth client; partitioning the second portion of the video cache to be accessible to the fourth client and inaccessible to the third client; receiving a third memory access request from the third client and simultaneously receiving a fourth memory access request from the fourth client; accessing the first portion of the video cache based on the third memory access request; and simultaneously accessing the second portion of the video cache based on the fourth memory access request.
Claim 3
Dependent Claim 28 words
The method of claim 1 wherein the mode indicator is for selecting between a two-dimensional mode (2D) of video operation and a three-dimensional (3D) mode of video operation.
Claim 4
Dependent Claim 31 words
The method of claim 1 , wherein during the first mode of cache operation the first and second portion of the video cache operate as a four-way set associative unified cache.
Claim 5
Dependent Claim 52 words
The method of claim 3 , wherein during the second mode of cache operation the first portion of the video cache operates as a two-way set associative cache for the third client and as the second portion of the video cache operates as a two-way set associative cache for the fourth client.
Claim 6
Dependent Claim 23 words
The method of claim 1 , wherein during the first mode of cache operation the first client is a 2D video destination client.
Claim 7
Dependent Claim 22 words
The method of claim 5 , wherein during the first mode of cache operation the second client is a video source client.
Claim 8
Dependent Claim 22 words
The method of claim 5 , wherein during the first mode of cache operation the second client is a video host client.
Claim 9
Dependent Claim 23 words
The method of claim 1 , wherein during the second mode of cache operation the third client is a 3D video destination client.
Claim 10
Dependent Claim 22 words
The method of claim 8 , wherein during the second mode of cache operation the fourth client is a Z video client.
Claim 11
Dependent Claim 22 words
The method of claim 8 , wherein during the second mode of cache operation the fourth client is a video host client.
Claim 12
Dependent Claim 79 words
The method of claim 1 , wherein the first mode of cache operation further includes the steps of: receiving a fifth memory access request from the first client and receiving a sixth memory access request from the second client; accessing a third word of the second portion of the video cache based on the fifth memory access request; and simultaneously accessing a fourth word of the second portion of the video cache based on the sixth memory access request.
Claim 13
Dependent Claim 88 words
The method of claim 11 wherein: the step of accessing the video cache based on the first memory access request is controlled by a first control portion; the step of accessing the first portion of the video cache based on the second memory access request is controlled by a second control portion; the method further including the steps of: allocating words in the first portion of the cache by the first control portion; and allocating words in the second portion of the cache by the second control portion.
Claim 14
Dependent Claim 25 words
The method of claim 12 , wherein allocating memory space of the first portion of the cache is controlled exclusively by the first control portion.
Claim 15
Dependent Claim 50 words
The method of claim 11 , wherein the first mode of operation includes storing the first and fifth memory access requests in a first and second location of a first pipeline; and storing the second and sixth memory access requests in a first and second location of a second pipeline.
Claim 16
Dependent Claim 69 words
The method of claim 14 wherein the step of accessing the first word includes thc sub-steps of: waiting to access the first word until the second word has been accessed, where the access to the first word is a write access, the access to the second word is a read access, and the second word and the first word are accessed at a same location in the first portion.
Claim 17
Dependent Claim 70 words
The method of claim 15 , wherein the step of accessing the first word includes the sub-step of: waiting to access the first word until the sixth word has been accessed, where the first word access is a write access, the sixth word access is a read access, and the sixth word and the first word are accessed at the same location in the first portion of the video cache.
Claim 18
Dependent Claim 30 words
The method of claim 15 , wherein the step of waiting includes: not receiving any new access requests by the second access pipeline until the first word has been written.

References Cited (Backward Citations)

US5392405A Cited
US5043874A Cited
US5581734A Cited
US5689656A Cited
US5974506A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 2004-01-09 2004-07-10 2005-01-09 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 2008-01-09 2008-07-10 2009-01-09 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 2012-01-09 2012-07-10 2013-01-09 $7700.00 Window Closed / Lapsed

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