Abstract: An integrated circuit has signal assist circuitry for assisting with pulling a signal on the signal line towards the logical low or high signal level. The signal assist circuitry comprises first and second assist circuits. The first assist circuit couples the signal line to the logical high signal level following a pullup transition of the signal and provides a floating signal level following a pulldown transition, while the second assist circuit provides the floating signal level following the pullup transition and provides the logical low signal level following the pulldown transition. By providing complementary first and second assist circuits, each circuit can be optimized for the opposite transition to achieve improved performance or power consumption.

Abstract: An integrated circuit has signal assist circuitry for assisting with pulling a signal on the signal line towards the logical low or high signal level. The signal assist circuitry comprises first and second assist circuits. The first assist circuit couples the signal line to the logical high signal level following a pullup transition of the signal and provides a floating signal level following a pulldown transition, while the second assist circuit provides the floating signal level following the pullup transition and provides the logical low signal level following the pulldown transition. By providing complementary first and second assist circuits, each circuit can be optimized for the opposite transition to achieve improved performance or power consumption.

Abstract: A multi-port memory cell of a multi-port memory array includes a first inverter that inverter is disabled by a first subset of write word lines and a second inverter, cross coupled with the first inverter, wherein the second inverter is disabled by a second subset of the plurality of write word lines. A first selection circuit has data inputs coupled to a first subset of a plurality of write bit lines, selection inputs coupled to the first subset of the plurality of write word lines, and an output coupled to the input of the second inverter. The second selection circuit has data inputs coupled to a second subset of the plurality of write bit lines, selection inputs coupled to the second subset of the plurality of write word lines, and an output coupled to the input of the first inverter.

Abstract: A multi-port memory cell of a multi-port memory array includes a first inverter that inverter is disabled by a first subset of write word lines and a second inverter, cross coupled with the first inverter, wherein the second inverter is disabled by a second subset of the plurality of write word lines. A first selection circuit has data inputs coupled to a first subset of a plurality of write bit lines, selection inputs coupled to the first subset of the plurality of write word lines, and an output coupled to the input of the second inverter. The second selection circuit has data inputs coupled to a second subset of the plurality of write bit lines, selection inputs coupled to the second subset of the plurality of write word lines, and an output coupled to the input of the first inverter.

Abstract: A method for accessing a content addressable memory (CAM) system having a CAM and random access memory (RAM) includes providing comparand data to the CAM, comparing the comparand data to entries of the CAM to determine a matching CAM entry and asserting a match signal corresponding to the matching CAM entry. In response to asserting the match signal, the method further includes providing output data, an output parity bit, and an output complement parity bit from the RAM, using the comparand data to generate a generated parity bit, and providing an error indicator based on the generated parity bit, the output parity bit, and the output complement parity bit. The error indicator may indicate an error when the generated parity bit is not equal to the output parity bit or when the output parity bit is equal to the output complement parity bit.

Abstract: A method for accessing a content addressable memory (CAM) system having a CAM and random access memory (RAM) includes providing comparand data to the CAM, comparing the comparand data to entries of the CAM to determine a matching CAM entry and asserting a match signal corresponding to the matching CAM entry. In response to asserting the match signal, the method further includes providing output data, an output parity bit, and an output complement parity bit from the RAM, using the comparand data to generate a generated parity bit, and providing an error indicator based on the generated parity bit, the output parity bit, and the output complement parity bit. The error indicator may indicate an error when the generated parity bit is not equal to the output parity bit or when the output parity bit is equal to the output complement parity bit.

Abstract: A cache design is described in which corresponding accesses to tag and information arrays are phased in time, and in which tags are retrieved (typically speculatively) from a tag array without benefit of an effective address calculation subsequently used for a corresponding retrieval from an information array. In some exploitations, such a design may allow cycle times (and throughput) of a memory subsystem to more closely match demands of some processor and computation system architectures. Our techniques seek to allow early (indeed speculative) retrieval from the tag array without delays that would otherwise be associated with calculation of an effective address eventually employed for a corresponding retrieval from the information array. Speculation can be resolved using the eventually calculated effective address or using separate functionality. In some embodiments, we use calculated effective addresses for way selection based on tags retrieved from the tag array.

Abstract: The present invention provides a latch circuit that is operable to generate a pulse from first and second clock signals to allow gates in a datapath to propagate data with minimal latency. The first clock signal is a version of the system clock and the second control signal is a time-shifted, inverted version of the system clock signal. Each of the individual latches in a datapath comprises data propagation logic. In one embodiment of the invention, the data propagation logic uses the first and second clock signals to generate an “implicit” pulse. In another embodiment of the invention, the data propagation logic uses the first and second clock signals to generate an “explicit” pulse. The implicit and explicit pulses are used to control the transmission gate of the latch to provide propagation of data through the latch with minimal latency.

Abstract: A method for pipelining a memory in an integrated circuit includes providing a first clock phase and providing a second clock phase, wherein the first clock phase and the second clock phase are at least partially non-overlapping. The method further includes providing a first memory array and providing a second memory array, wherein the second memory array shares a wordline with the first memory array. The method further includes using said wordline to select at least one row of the first memory array during the first clock phase. The method further includes using said wordline to select at least one row of the second memory array during the second clock phase.

Abstract: A cache design is described in which corresponding accesses to tag and information arrays are phased in time, and in which tags are retrieved (typically speculatively) from a tag array without benefit of an effective address calculation subsequently used for a corresponding retrieval from an information array. In some exploitations, such a design may allow cycle times (and throughput) of a memory subsystem to more closely match demands of some processor and computation system architectures. In some cases, phased access can be described as pipelined tag and information array access, though strictly speaking, indexing into the information array need not depend on results of the tag array access. Our techniques seek to allow early (indeed speculative) retrieval from the tag array without delays that would otherwise be associated with calculation of an effective address eventually employed for a corresponding retrieval from the information array.

Abstract: A method for pipelining a memory in an integrated circuit includes providing a first clock phase and providing a second clock phase, wherein the first clock phase and the second clock phase are at least partially non-overlapping. The method further includes providing a first memory array and providing a second memory array, wherein the second memory array shares a wordline with the first memory array. The method further includes using said wordline to select at least one row of the first memory array during the first clock phase. The method further includes using said wordline to select at least one row of the second memory array during the second clock phase.

Abstract: The present invention provides a latch circuit that is operable to generate a pulse from first and second clock signals to allow gates in a datapath to propagate data with minimal latency. The first clock signal is a version of the system clock and the second control signal is a time-shifted, inverted version of the system clock signal. Each of the individual latches in a datapath comprises data propagation logic. In one embodiment of the invention, the data propagation logic uses the first and second clock signals to generate an “implicit” pulse. In another embodiment of the invention, the data propagation logic uses the first and second clock signals to generate an “explicit” pulse. The implicit and explicit pulses are used to control the transmission gate of the latch to provide propagation of data through the latch with minimal latency.