Fujitsu Corporation

Advanced Micro Devices Corporation

James Vinh

Ganesh Venkataramanan

Pranjal Srivastava

Kyle Viau

Srikanth Arekapudi

Nital P Patwa

Michael Butler

Robert S Grondalski

Mike Butler

Ajay Naini

Bob Grondalski

A method for comparing content addressable memory (CAM) elements is disclosed. Binary values are stored in a pair of CAM elements. A comparison value is provided to a group of comparators, the comparison value based on the binary value stored in the pair of CAM elements. A match value is provided to the group of comparators, the match value corresponding to a binary value pair to be compared with the binary value stored in the pair of CAM elements. A positive match result value is output from a selected group of comparators via an output line in response to the comparison value matching the match value.

Selectable multi-way comparator

A method and processor are described for implementing programmable priority encoding to track relative age order of operations in a scheduler queue. The processor may comprise a scheduler queue configured to maintain an ancestry table including a plurality of consecutively numbered row entries and a plurality of consecutively numbered columns. Each row entry includes one bit in each of the columns. Pickers are configured to pick an operation that is ready for execution based on the age of the operation as designated by the ancestry table. The column number of each bit having a select logic value indicates an operation that is older than the operation associated with the number of the row entry that the bit resides in.

Method and apparatus for prioritizing processor scheduler queue operations

Content-Addressable Memory (CAM) arrays and related circuitry for integrated circuits and CAM array comparison methods are provided such that relatively low power is used in the operation of the CAM circuitry. A binary value pair is stored in a pair of CAM memory elements. A comparison signal is provided to comparator circuitry that uniquely represents the stored binary values. A match signal is input to the comparator circuitry that uniquely represents a binary value pair to be compared with the stored binary value pair. In one example, a transistor is operated to output a positive match result signal only on a condition that the comparison signal provided to the comparator circuitry and match signal input to the comparator circuitry represent the same binary value pair. In that example, no transistor of the comparator circuitry is operated when the comparison signal provided to the comparator circuitry and match signal input to the comparator circuitry represent different binary value pairs.

Low power content-addressable memory and method

A complementary metal oxide semiconductor (CMOS) circuit is described. The CMOS circuit includes a plurality of CMOS gates, a plurality of logic inputs and a logic output. Each CMOS gate is connected to a negative power supply terminal (Vss) and a positive power supply terminal (Vdd). The CMOS circuit further includes parasitic nets connected to the CMOS gates, and net pulldown circuits for eliminating a charge accumulation on the parasitic nets while avoiding potential short circuit conditions. The CMOS gates may be OR-AND-INVERT (OAI) gates or AND-OR-INVERT (AOI) gates.

CMOS circuit with dynamic parasitic net pulldown circuit

A method and apparatus for protecting dynamic logic circuits from the effects of noise at the inputs to the dynamic logic circuits is disclosed. Parallel current flow or evaluate paths which couple an output node through a common node to a low voltage or ground rail include extra transistors in the current flow or evaluate path to allow the inputs to be protected while maintaining the operation and integrity of the circuit.

Method and apparatus for reduction of noise sensitivity in dynamic logic circuits

A new self clocking family of dynamic logic gates which replace footless or subsequent stage dynamic logic gates in multi-stage domino logic circuits. In a preferred embodiment, a multi-stage logic circuit is designed having a first stage which utilizes a traditional dynamic logic gate and a second stage which includes a new self-clocking dynamic logic gate. The output from the first stage is coupled to the input of the second stage such that the second stage is not dependent upon any type of clock signal for precharging. Instead, the second stage includes a dual transistor arrangement on the inter-stage inputs (i.e. the outputs from one stage which are input to subsequent stages) in order to precharge the output node at the second stage such that no type of clock signal is needed during precharge. Accordingly, the output from the second stage is efficiently precharged without using a delayed clock signal or any customized delay circuitry while minimizing through current by design. This allows the multi-stage domino logic circuit to be designed with lower power consumption since through current is minimized by design. The second stage further includes a noise/leakage circuit at each of the inputs to the second stage. The noise/leakage circuit is designed to ensure a stable and accurate output from the new self-clocking dynamic logic circuit until the inputs to that stage are valid. The noise/leakage circuit also protects against any improper operation which may be caused by any noise on the input lines.

Method and apparatus for a family of self clocked dynamic circuits

A static latch includes two individual data paths. A first data path is used for passing the data on an output driver for driving a voltage level at the output from the latch toward a logic high or logic low voltage level depending upon the data. A second data path is used for storing the data in a feedback sturcutre so the latch can continue to drive the voltage level at the output node until the next data is loaded into the latch.

High speed static latch

An apparatus for high speed signal propagation across a net in an integrated circuit operates with a driver that is coupled to the net, for driving signals across the net. A first transition assist driver (TAD) is coupled to a first node in the net and is capable of pulling the voltage level of the first node in response to the voltage level of the first node reaching a threshold value. The threshold value can be adjusted in order to increase the switching speed or, alternatively, the noise immunity of the first TAD. A second TAD is coupled to a second node in the net and is capable of pulling the voltage level of the second node in response to the voltage level of the second node reaching the threshold value. The apparatus is used for increasing the propagation speed of signals that are transmitted in a microprocessor block or other stages in an integrated circuit. A method for high speed signal propagation in an integrated circuit by use of a signal propagation system includes the steps of: (a) sensing a voltage level of a first node in a net; and (b) pulling the voltage level of the first node in response to the voltage level of the first node reaching a threshold value. This method is applicable without any modification when the net can be driven by one of the multiple drivers attached to the net. In other words, the method allows bi-directional signal propagation.

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San Jose, CA, United States of America

James Vinh