Abstract: A source-synchronization interface circuit includes: a sender synchronous-to-asynchronous protocol converter that receives sender data and a sender clock and that has regenerative gain to resolve metastability during phase synchronization of the sender clock and a receiver clock; an asynchronous FIFO buffer with multiple stages that conveys phase information and data from the sender synchronous-to-asynchronous protocol converter to a receiver synchronous-to-asynchronous protocol converter; and a receiver synchronous-to-asynchronous protocol converter that receives the receiver clock and that has regenerative gain to resolve metastability during the phase synchronization.

Abstract: A source-synchronization interface circuit includes: a sender synchronous-to-asynchronous protocol converter that receives sender data and a sender clock and that has regenerative gain to resolve metastability during phase synchronization of the sender clock and a receiver clock; an asynchronous FIFO buffer with multiple stages that conveys phase information and data from the sender synchronous-to-asynchronous protocol converter to a receiver synchronous-to-asynchronous protocol converter; and a receiver synchronous-to-asynchronous protocol converter that receives the receiver clock and that has regenerative gain to resolve metastability during the phase synchronization.

Abstract: A clock deskew circuit for transferring data from a first clock domain to a second clock domain. This circuit includes a data path, which has: a transmitter latch controlled by a transmitter clock in a first clock domain; a receiver latch controlled by a receiver clock in a second clock domain; and an intermediate latch coupled between the transmitter latch and the receiver latch. The transmitter clock and the receiver clock have an unknown phase offset. The circuit additionally includes a control circuit coupled between the transmitter clock and the receiver clock, and generates a control clock for the immediate latch based on the transmitter clock and the receiver clock. The control circuit selects between a first operation mode and a second operation mode for the data path circuit based at least on the phase relationship of the control clock with respect to the transmitter clock and the receiver clock.

Abstract: The disclosed embodiments provide a system that filters pre-fetch requests to reduce pre-fetching overhead. During operation, the system executes an instruction that involves a memory reference that is directed to a cache line in a cache. Upon determining that the memory reference will miss in the cache, the system determines whether the instruction frequently leads to cache misses. If so, the system issues a pre-fetch request for one or more additional cache lines. Otherwise, no pre-fetch request is sent. Filtering pre-fetch requests based on instructions' likelihood to miss reduces pre-fetching overhead while preserving the performance benefits of pre-fetching.

Abstract: The disclosed embodiments provide a system that uses speculative cache requests to reduce cache miss delays for a cache in a multi-level memory hierarchy. During operation, the system receives a memory reference which is directed to a cache line in the cache. Next, while determining whether the cache line is available in the cache, the system determines whether the memory reference is likely to miss in the cache, and if so, simultaneously sends a speculative request for the cache line to a lower level of the multi-level memory hierarchy.

Abstract: The disclosed embodiments provide a synchronization circuit that supports multiple parallel reads and writes. This synchronization circuit includes multiple coupled data storage locations that synchronize data and control signals between two time domains and control logic that facilitates simultaneously accessing a variable number of such data storage locations in the same clock cycle. During operation, the synchronization circuit receives a request to simultaneously access (e.g., read and/or write) two or more synchronized data storage locations. In response to the request, the control logic in the synchronization circuit determines whether the present state of the synchronization circuit can accommodate the request, and if so, simultaneously accesses two or more synchronized data storage locations.

Abstract: Embodiments of a synchronization circuit are described. This synchronization circuit includes multiple selectively coupled synchronization stages which are configurable to synchronize data and control signals between a first time domain and a second time domain, where the synchronization can be performed based on asynchronous or synchronous events associated with either the first time domain or the second time domain. Additionally, the synchronization circuit includes control logic, coupled to the synchronization stages, which is configured to adapt a number of synchronization stages used to synchronize the data and the control signals based on an estimate of a probability of metastability persisting to an output of the synchronization circuit during the synchronization.

Abstract: The disclosed embodiments provide a system that filters pre-fetch requests to reduce pre-fetching overhead. During operation, the system executes an instruction that involves a memory reference that is directed to a cache line in a cache. Upon determining that the memory reference will miss in the cache, the system determines whether the instruction frequently leads to cache misses. If so, the system issues a pre-fetch request for one or more additional cache lines. Otherwise, no pre-fetch request is sent. Filtering pre-fetch requests based on instructions' likelihood to miss reduces pre-fetching overhead while preserving the performance benefits of pre-fetching.

Abstract: The disclosed embodiments provide a synchronization circuit that supports multiple parallel reads and writes. This synchronization circuit includes multiple coupled data storage locations that synchronize data and control signals between two time domains and control logic that facilitates simultaneously accessing a variable number of such data storage locations in the same clock cycle. During operation, the synchronization circuit receives a request to simultaneously access (e.g., read and/or write) two or more synchronized data storage locations. In response to the request, the control logic in the synchronization circuit determines whether the present state of the synchronization circuit can accommodate the request, and if so, simultaneously accesses two or more synchronized data storage locations.

Abstract: The disclosed embodiments provide a system that uses speculative cache requests to reduce cache miss delays for a cache in a multi-level memory hierarchy. During operation, the system receives a memory reference which is directed to a cache line in the cache. Next, while determining whether the cache line is available in the cache, the system determines whether the memory reference is likely to miss in the cache, and if so, simultaneously sends a speculative request for the cache line to a lower level of the multi-level memory hierarchy.

Abstract: Embodiments of a synchronization circuit are described. This synchronization circuit includes multiple selectively coupled synchronization stages which are configurable to synchronize data and control signals between a first time domain and a second time domain, where the synchronization can be performed based on asynchronous or synchronous events associated with either the first time domain or the second time domain. Additionally, the synchronization circuit includes control logic, coupled to the synchronization stages, which is configured to adapt a number of synchronization stages used to synchronize the data and the control signals based on an estimate of a probability of metastability persisting to an output of the synchronization circuit during the synchronization.

Abstract: A method of determining effective bandwidth includes selecting a first packet size and sending a first packet having the first packet size from a first node to a second node. A confirmation that the first packet was received in the second node is received. A transfer time of the first packet is recorded. A second packet size is selected and a second packet having the second packet size is sent from the first node to the second node. A confirmation that the second packet was received in the second node is received and a transfer time of the second packet is recorded. An effective bandwidth between the first node and the second node is calculated and the effective bandwidth can be output.

Abstract: One embodiment of the present invention provides a system which drives on-chip wires using capacitive coupling. During operation, the system drives a signal onto a driven wire. This signal feeds from the driven wire through a coupling capacitor onto a coupled wire, which is an on-chip wire that routes the signal to its destination. Feeding the signal through the coupling capacitor reduces the voltage swing of the corresponding coupled signal on the coupled wire, thereby lessening the power required to drive the coupled signal on the coupled wire.

Abstract: A method for determining a number of colors in a digital image includes receiving a digital image and determining a total number of pixels in the digital image. A proportion of the total number of pixels is selected as having an infrequent color and a respective color for each one of a first portion of the pixels is determined. The respective colors are analyzed to determine whether the respective colors include greater than or equal to the selected proportion infrequent color. If the respective colors include greater than or equal to the selected proportion of infrequent colors then a first subsequent process is selected. If the respective colors include less than the selected proportion of pixels having the infrequent color then a second subsequent process is selected. A system for determining a number of colors in a digital image is also described.

Abstract: A system for compressing an image. The system determines a set of commonly occurring color values in the image and associates a designator with each commonly occurring color value. For each pixel in the image, the system identifies a color value for the pixel. If the pixel has a commonly occurring color value, the system substitutes the associated designator for the commonly occurring color value. Otherwise, if the pixel does not have a commonly occurring color value, the system adds the color value to a rare color list, and substitutes a special designator for the color value to indicate that the color value for the pixel is contained in the rare color list.

Abstract: One embodiment of the present invention provides a system which drives on-chip wires using capacitive coupling. During operation, the system drives a signal onto a driven wire. This signal feeds from the driven wire through a coupling capacitor onto a coupled wire, which is an on-chip wire that routes the signal to its destination. Feeding the signal through the coupling capacitor reduces the voltage swing of the corresponding coupled signal on the coupled wire, thereby lessening the power required to drive the coupled signal on the coupled wire.

Abstract: One embodiment of the present invention provides a system for compressing an image. During operation, the system determines a set of commonly occurring color values in the image and associates a designator with each commonly occurring color value. Next, for each pixel in the image, the system identifies a color value for the pixel. If the pixel has a commonly occurring color value, the system substitutes the associated designator for the commonly occurring color value. Otherwise, if the pixel does not have a commonly occurring color value, the system adds the color value to a rare color list, and substitutes a special designator for the color value to indicate that the color value for the pixel is contained in the rare color list.