Late-select, address-dependent sense amplifier
Sense amplifiers in a memory may be activated and deactivated. In one embodiment, a processor may include a memory. The memory may include a number of sense amplifiers. Based on a late arriving address bit of an address used to access data from the memory, a sense amplifier may be activated while another sense amplifier may be deactivated.
1. A memory, comprising:
a first array coupled to an input of a first output sense amplifier; and
a second array coupled to an input of a second output sense amplifier;
wherein an output of the first output sense amplifier and an output of the second output sense amplifier are coupled together;
wherein the first output sense amplifier is configured to be receive a first enable signal, and the second output sense amplifier is configured to receive a second enable signal;
wherein the first and the second enable signals are derived from an address bit of an address used to access the memory;
wherein the first and the second enable signals are active mutually exclusive.
2. The memory of claim 1 , wherein the first output sense amplifier and second output sense amplifier are each configured to be in a low power mode when not enabled.
3. The memory of claim 1 , wherein the respective outputs of the first output sense amplifier and second output sense amplifier are further coupled to an input of an output driver.
4. The memory of claim 1 , wherein the first output sense amplifier and second output sense amplifier are each configured to receive their respective enable signals after the start of a clock cycle in which data is read from the memory.
5. The memory of claim 1 , wherein the address bit is a late arriving physical address bit.
6. An apparatus, comprising:
a first sense amplifier and a second sense amplifier, wherein each sense amplifier is configured to receive a respective indication to activate, wherein the respective indications are active mutually exclusive, and wherein each sense amplifier is further configured to output a respective cache line of data;
wherein the respective activation indication for a given sense amplifier is selected by an address bit of an address for accessing the respective cache line of data.
7. The apparatus of claim 6 , further comprising:
a first cache array configured to provide a first cache line of data to the first sense amplifier; and
a second cache array configured to provide a second cache line of data to the second sense amplifier, wherein each cache array is further configured to receive a portion of the address for accessing the respective cache line of data.
8. The apparatus of claim 7 , wherein the portion of the address for accessing each respective cache line of data is the same portion of the address.
9. The apparatus of claim 7 , wherein during a period in which the first sense amplifier is enabled, the first cache line of data is the outputted cache line of data.
10. The apparatus of claim 9 , wherein the second cache line of data is different than the outputted cache line of data.
11. A system, comprising:
a memory; and
one or more processors coupled to the memory, wherein at least one of the one or more processors includes a data cache;
wherein the data cache comprises:
a first cache array configured to provide a first cache line of data to a first sense amplifier, and
a second cache array configured to provide a second cache line of data that is different than the first cache line of data to a second sense amplifier, wherein the first sense amplifier is configured to receive a first enable signal and the second sense amplifier is configured to receive a second enable signal, wherein the first and second enable signals are based on an address bit of an address used to access the data cache, and wherein the first and second enable signals are not configured to be enabled simultaneously.
12. The system of claim 11 , wherein during a period in which the first enable signal is asserted, the first sense amplifier is enabled and configured to output the first cache line of data to an execution core of the at least one processor, and the second sense amplifier is disabled.
13. The system of claim 11 , wherein a portion of the address used to access the data cache, excluding at least the address bit, is provided to the first and second cache arrays to retrieve the first cache line of data and second cache line of data, respectively, wherein the first and second cache lines of data differ in at least one bit of data.
14. The system of claim 11 , wherein an output of the first sense amplifier is coupled to an output of the second sense amplifier, wherein the coupled outputs are coupled to a driver configured to provide the first or second cache line of data to an execution core of the at least one processor.
15. The system of claim 11 , wherein during operation, the address used to access the data cache, excluding at least the address bit, is received by the first and second cache arrays before the first and second enable signals are received by the first and second sense amplifiers, respectively.
16. A method, comprising:
a first array and second array of a memory receiving a portion of an address used to access the memory before a start of a clock cycle;
the first array providing a first line of data to a first sense amplifier;
the second array providing a second line of data to a second sense amplifier; and
after the start of the clock cycle, the first sense amplifier receiving a first sense enable signal and the second sense amplifier receiving a second sense enable signal, wherein the first and second sense enable signals are derived from another portion of the address, and wherein an output of the first sense amplifier is coupled to an output of the second sense amplifier.
17. The method of claim 16 , wherein the another portion of the address arrives later in time than the portion of the address.
18. The method of claim 16 , wherein the first and second sense enable signals are active mutually exclusive, wherein each respective indication is capable of being in an enabled or disabled state.
19. The method of claim 16 , further comprising:
logic asserting the first sense enable signal and other logic deasserting the second sense enable signal;
activating the first sense amplifier in response to the asserted first enable signal without activating the second sense amplifier; and
the first sense amplifier outputting the first line of data.
20. The method of claim 19 , further comprising:
the first and second arrays receiving a portion of a next address used to access the memory before a start of a next clock cycle;
after the start of the next clock cycle, the first and second sense amplifiers receiving the first and second enable signals that are derived from another portion of the next address, wherein the another portion of the next address arrives later in time than the portion of the address;
logic asserting the second sense enable signal and deasserting the first sense enable signal;
activating the second sense amplifier in response to the asserted second enable signal and deactivating the first sense amplifier in response to the deasserted first enable signal; and
the second sense amplifier outputting the second line of data.