Shared cache wordline decoder for redundant and regular addresses
First Claim
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1. An apparatus for accessing data in a memory, the apparatus comprising:
- a bit vector replacement circuit to receive a first bit vector and a control signal and to substitute a constant bit vector for the first bit vector, in response to the control signal being in a first state, to produce a second bit vector;
a pre-decoder coupled with the bit vector replacement circuit to receive a plurality of bit vectors including the second bit vector, to combine subsequences from the plurality of bit vectors to identify possible wordline subsequences corresponding to the plurality of bit vectors, and to activate a subsequence indicator for an identified possible wordline subsequence; and
a wordline decoder coupled with the pre-decoder to combine activated subsequence indicators to identify a unique wordline corresponding to the plurality of bit vectors.
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Abstract
In one embodiment, a wordline decoder provides access to cache memory locations when addresses are bypassed directly from arithmetic circuitry in redundant form. The wordline decoder is also designed to provide access to cache memory locations when addresses are received from registers in an unsigned binary form. The combined functionality is provided in a pre-decode circuit by selectively replacing one of a plurality of redundant bit vectors with a constant bit vector when redundant addressing is not enabled.
52 Citations
33 Claims
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1. An apparatus for accessing data in a memory, the apparatus comprising:
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a bit vector replacement circuit to receive a first bit vector and a control signal and to substitute a constant bit vector for the first bit vector, in response to the control signal being in a first state, to produce a second bit vector; a pre-decoder coupled with the bit vector replacement circuit to receive a plurality of bit vectors including the second bit vector, to combine subsequences from the plurality of bit vectors to identify possible wordline subsequences corresponding to the plurality of bit vectors, and to activate a subsequence indicator for an identified possible wordline subsequence; and a wordline decoder coupled with the pre-decoder to combine activated subsequence indicators to identify a unique wordline corresponding to the plurality of bit vectors. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. A digital computing system comprising:
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a die; a bit vector selection circuit on the die to receive a first bit vector and a control signal, and to select a constant bit vector or the first bit vector responsive to the control signal, and to output the selected bit vector as a second bit vector; a decoder circuit on the die coupled to the bit vector selection circuit to receive a plurality of bit vectors including the second bit vector and to combine a subsequence from each of the plurality of bit vectors to identify a wordline corresponding to the plurality of bit vectors; an internal cache on the die, the internal cache coupled with the decoder circuit to store a first datum at the wordline corresponding to the plurality of bit vectors; a processor on the die coupled with the decoder circuit to produce the plurality of bit vectors; and an external cache, not on the die, to store a second datum, the external cache coupled with the die and with the internal cache, to transmit the second datum to the internal cache to be stored on the die. - View Dependent Claims (20, 21, 22, 23)
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24. A cache memory system comprising:
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a plurality of lines for storing copies of memory storage locations having corresponding addresses; means for decoding an address to access a line of the cache memory system responsive to an access request that includes an address represented in a redundant form; and means for decoding an address to access a line of the cache memory system responsive to an access request that includes an address represented in unsigned binary form. - View Dependent Claims (25, 26, 27, 28, 29)
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30. A method of accessing data in a first storage, the method comprising:
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copying a plurality of storage locations from a second storage into a plurality of wordlines of the first storage by asserting corresponding wordline signals; receiving an access request including a first bit vector, a second bit vector and a control signal; setting the second bit vector equal to a constant bit vector if the control signal is in a first state; identifying at least in part from the second bit vector and from the first bit vector a word line corresponding to the combined first bit vector and second bit vector; asserting the identified wordline signal; and accessing the wordline of the first storage corresponding to the assertedword line signal. - View Dependent Claims (31, 32, 33)
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Specification