Translation lookaside buffer shutdown scheme
First Claim
1. A content addressable memory apparatus comprising:
- a plurality of tag registers;
a plurality of data registers, each data register having an output enable for enabling contents of the data register onto an output bus;
means for loading information into a first one of the tag registers independently of contents of a second one of the tag registers;
a plurality of comparators, each of the comparators corresponding with a respective one of the tag registers and generating a match signal indicative of whether contents of the respective one of the tag registers matches an incoming tag signal;
first detection means for activating a multiple match signal when at least a given number of the comparators generate match signals indicating contents of respective ones of the tag registers match the incoming tag signal, the given number being greater than one; and
means for coupling each of the match signals to a respective one of the output enables, the means for coupling to all of the output enables being inhibited if the multiple match signal is active.
3 Assignments
0 Petitions
Accused Products
Abstract
An apparatus for temporarily disabling a translation lookaside buffer in a computer system upon the occurrence of certain predefined system conditions. Such conditions may be of a first type which have been predetermined to indicate a greater risk that two or more virtual addresses stored in the TLB will simultaneously match the incoming virtual address, and/or of a second type in which access to the TLB is not needed. An example of the first type is a reference to an unmapped segment of memory. An example of the second type is the processing of a non-memory-access instruction. The apparatus may further include failsafe circuitry to shut down the TLB if at least a given number of matches occur at any time and for any reason, the given number being greater than 1. The apparatus prevents loss of data or damage to the chip where match comparisons are performed in parallel.
-
Citations
10 Claims
-
1. A content addressable memory apparatus comprising:
-
a plurality of tag registers; a plurality of data registers, each data register having an output enable for enabling contents of the data register onto an output bus; means for loading information into a first one of the tag registers independently of contents of a second one of the tag registers; a plurality of comparators, each of the comparators corresponding with a respective one of the tag registers and generating a match signal indicative of whether contents of the respective one of the tag registers matches an incoming tag signal; first detection means for activating a multiple match signal when at least a given number of the comparators generate match signals indicating contents of respective ones of the tag registers match the incoming tag signal, the given number being greater than one; and means for coupling each of the match signals to a respective one of the output enables, the means for coupling to all of the output enables being inhibited if the multiple match signal is active. - View Dependent Claims (2, 3, 4, 5)
-
-
6. A content addressable memory apparatus comprising:
-
a plurality of tag registers; a plurality of data registers, each data register having an output enable for enabling contents of the data register onto an output bus; means for loading information into a first one of the tag registers independently of contents of a second one of the rag registers; a plurality of comparators, each of the comparators corresponding with a respective one of the tag registers and generating a match signal indicative of whether contents of the respective one of the tag registers matches an incoming tag signal; first detection means for activating a multiple match signal when at least a given number of the comparators generate match signals indicating contents of respective ones of the tag registers match the incoming tag signal, the given number being greater than one; and means for coupling each of the match signals to a respective one of the output enables, the means for coupling to all of the output enables except a preselected one of the output enables being inhibited if the multiple match signal is active. - View Dependent Claims (7, 8, 9, 10)
-
Specification