Validity status information storage within a data processing system
OwnerDavid Michael Bull, Peter Guy Middletoninventors
Life of this patent
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Abstract
A valid memory 2 is provided storing valid words 8 with bit positions indicating whether corresponding cache lines within a cache memory 7 store valid data. Flip-flop circuits 4 are provided to indicate whether or not the valid words 8 within the valid memory 2 are themselves valid. The number of valid words 8 corresponding to an individual flip-flop circuit 4 varies in dependence upon the size of the valid memory 2. Thus, for example, a single flip-flop circuit 4 may indicate whether one, two, four or eight valid words 8 from the valid memory 2 are storing valid data depending upon the particular size of the valid memory 2 employed.
Claims12
Apparatus for processing data, said apparatus comprising:
- (i) a valid word memory operable to store a plurality of valid words, each valid word having bits representing whether or not corresponding data storage locations in a further memory are storing valid data;
- and
- (ii) a plurality of flip-flop circuits operable to store values indicative of whether or not corresponding valid words within said valid memory are themselves valid;
- characterised in that
- (iii) a flip-flop circuit is operable to store a value indicative of validity of a number of valid words which varies in dependence upon how many valid words may be stored in said valid memory.
A method of processing data, said method comprising the steps of:
- (i) storing a plurality of valid words within a valid word memory, each valid word having bits representing whether or not corresponding data storage locations in a further memory are storing valid data;
- and
- (ii) storing within a plurality of flip-flop circuits values indicative of whether or not corresponding valid words within said valid memory are themselves valid;
- characterised in that
- (iii) a flip-flop circuit stores a value indicative of validity of a number of valid words which varies in dependence upon how many valid words may be stored in said valid memory.
Dependencies are inferred from the claim text.