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Cache memory having a read-modify-write operation and simultaneous burst read and write operations and a method therefor
| Details |
Inventors: Jones, Kenneth W.; Bader, Mark D.; Kahlich, Arthur D.;
Assignee: Motorola, Inc. (Schaumburg, IL)
Primary Examiner: Chan; Eddie P.
Assistant Examiner: Kim; Hong C.
Attorney, Agent or Firm: Hill; Daniel D.
A multiple-way, set associative cache memory (20) allows burst read and burst write operations to occur simultaneously on different columns within a memory block during a read-modify-write operation. This is accomplished by using a write column logic (47) and a read column logic (51) to delay write column decode signals by one clock cycle from the read column decode signals. When data is being burst into and out of the cache during the read-modify-write operation, the first read cycle from the cache array (40) occurs, and one clock cycle later, the first write cycle occurs. The first write cycle occurs during the same time interval as the second read cycle. This increases the speed of a read-modify-write operation, relaxes timing constraints on the read and write operations, while reducing the power consumption of the cache. |
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DETAILED DESCRIPTION Accordingly, there is provided, in one form, a cache memory having a plurality of memory cells, a word line decoding circuit, and column decoding logic.
The word line decoding circuit is coupled to the plurality of memory cells, and selects a word line in response to an address.
The column decoding logic is coupled to the plurality of memory cells, and is for selecting a first memory cell to receive data and a second memory cell to provide data, the column decoding logic selecting the first and second memory cells during a first clock signal.
The first data signal is provided to the first selected memory cell and the second data signal is received from the second selected memory cell during a same time interval.
In another embodiment, a method for performing a read-modify-write operation in multiple-way, set associative cache memory is provided.
These and other features and advantages will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings.
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