Abstract: A plasma absorption wave limiter is disclosed. The plasma absorption wave limiter comprises a limiting layer and a trigger layer. The limiting layer is transmissive in a pass band of a sensor and capable of generating a reflective and absorptive free electron plasma that will propagate and dissipate therein. The trigger layer is located aft of and in contact with the limiting layer and is capable of residually absorbing incident radiation and initiating the thermal plasma wave in the limiting layer responsive to a threat.

Abstract: A system and method for selectively injecting parity errors into instructions of a data processing system when the instructions are copied from a read buffer to a first level cache. The parity errors are selectively injected according to programmable indicators, each programmable indicator being associated with one or more instructions stored in the read buffer. The error-injection system also includes programmable operating modes whereby error injection will occur during, for example, every copy back from the read buffer to the first level cache, or alternatively, during only a selected copy back sequence. The system allows for comprehensive testing of error detection and recovery logic in an instruction processor, and further allows for comprehensive testing of the logic associated with performing a data re-fetch from a second level cache or storage device.

Abstract: A data processor is disclosed that executes a number of microcode instruction words. Each of the microcode instruction words has a bit field reserved to indicate which, if any, event counters are to be incremented. This enables the number of executions of a particular microcode instruction word to be counted. By simply changing the microcode bits in the bit fields of the microcode instruction words, the event counter can be programmed to count any number or pattern of microcode instruction word executions. In one embodiment, there is a one-to-one correspondence between each bit in the bit field and each event counter. In another system, the bits in the bit field are decoded to provide an address that selects selected event counters.

Abstract: Method for performing critical path timing analysis on a circuit design having different timing constraints for multiple parallel paths. Method includes clearing the state of the circuit design, setting control lines in the circuit design to a selected set of control signals, and identifying blocking nets of the circuit design to be flagged for timing analysis by simulating the circuit design with the selected set of control signals as input signals. Identified blocking points are added to a list which identifies paths in the circuit design to be analyzed. All possible sets of control signals are processed. Timing analysis is then performed on the circuit design using the list as input data. A critical step is the identification of the blocking points. Blocking points are identified for each net input to a gate in the circuit design having an unknown value, and a known value on an output net from the gate for the selected set of control signals.

Abstract: Method and apparatus for performing microcode paging during instruction execution in an instruction processor. In a preferred embodiment an instruction processor is provided that includes both a microcode ROM and a microcode RAM. The microcode ROM stores the current release of the microcode for the computer system, and the microcode RAM stores microcode patch instructions. During instruction execution, the present invention selects between the output of the microcode ROM and the microcode RAM, depending on whether the instruction requires a patch microcode instruction. If the desired microcode patch instruction is not stored in the microcode RAM, the instruction processor is temporarily interrupted and the desired microcode patch instruction or a group of microcode patch instructions are written, or paged, into the microcode RAM.

Abstract: A method and apparatus for efficiently identifying and resolving conflicts between conflicting cell substitution recommendations. Unlike the prior art, the present invention provides a resolving means within a data processing system to identify and resolve conflicting cell substitution recommendations. The resolving means may categorize the cell substitutions in accordance with a number of predetermined cell substitution types, wherein each of the cell substitution type may be assign a predetermined priority value. Thereafter, the resolving means may identify conflicting cell substitution recommendations, and resolve the conflicts in accordance with the predetermined priority scheme.

Abstract: A method and apparatus for efficiently optimizing a circuit design by substituting identified cells within the circuit design with logically equivalent cells having different drive strengths. The present invention eliminates the need to update the design database and to place and route the circuit design during each design iteration. Rather, an improved extraction tool is provided which incorporates a cell substitution list, and updates the RC file therefrom. The updated RC file is used by the timing analysis tool to determine if the updated design will meet the design specification. After the design meets the design specification, a final place and route may be performed.

Abstract: A method and apparatus for efficiently performing timing analysis on a circuit design. The present invention essentially provides a hybrid between a path enumeration algorithm and a critical path algorithm. As such, the present invention increases the number and degree of timing violations reported by a Critical Path Analysis (CPA) algorithm, while maintaining a performance advantage over a Path Enumeration (PE) algorithm. This is accomplished by providing a number of "pseudo" clocks to selected latches within the circuit design database, thereby tricking the CPA algorithm into reporting more timing violations than would otherwise be reported.

Abstract: A self-timing clock generator for use with a precharged Static Random Access Memory (SRAM). The invention asynchronously switches the memory clock pulse to a precharge signal upon recognition of completion of a memory access cycle. Recognition of completion of the memory access cycle is performed in one of two ways. The first method monitors for the existence of a preprogrammed memory-completion bit which becomes active at the same time that read or write data becomes valid at the data outputs. The second method monitors for the existence of a memory-completion bit generated through the use of an odd parity generator. An alternate clocking method is provided to bypass the asynchronous self-timing clock generator, and to allow for synchronous clocking of the precharged SRAM. An external clocking method is also provided to directly clock the precharged SRAM.