Abstract: A computer system, method, and controller bus agent for control access to a computer bus. The computer system includes a parallel architecture in which plural bus agents are directly coupled to the computer bus. Each bus agent includes plural bus requester ports each coupled to a different bus requester. As such, the computer system employs a relatively flat, parallel architecture that handles bus requests from the bus requesters in parallel. The controller bus agent includes an internal arbiter and an external arbiter. The internal arbiter arbitrates between bus requests received from the plural bus requesters coupled to the controller bus agent. The external arbiter arbitrates between the bus requests received from other bus agents and from the internal arbiter.

Abstract: A superscalar microprocessor predecodes instruction data to identify the boundaries of instructions and the type of instruction. To expedite the dispatch of instructions, when a cache line is scanned, the first scanned instruction is predicted to be a microcode instruction and is dispatched to the MROM unit. A microcode scan circuit uses the microcode pointer and the functional bits of the predecode data to multiplex instruction specific bytes of the first microcode instruction to the MROM unit. If the predicted first microcode instruction is not the actual first microcode instruction, then in a subsequent clock cycle, the actual microcode instruction is dispatched the MROM unit and the incorrectly predicted microcode instruction is canceled.

Abstract: A memory package for storing data and capable of being added to or replaced while being provided with a battery backup in computer systems which can be mounted with a plurality of said memory packages. A memory package also has a function to reduce power consumption of the battery backup to a minimum, when the memory package with battery backup is inserted into the computer system without the main power being applied. Consequently, even if additional memory packages are inserted in computer systems installable with memory packages having battery backups, only a weak current need be supplied from the backup power supply so that the battery will not run down after a short time. The memory packages can therefore be added and replaced while still storing data internally and the memory capacity can be changed.

Abstract: A processor includes at least an execution unit that executes an instruction by performing an operation indicated by the instruction utilizing one or more operands and condition code logic that determines less than, greater than, and equal to condition code bits associated with the instruction concurrently with execution of the instruction by the execution unit. In one embodiment, the condition code logic includes a single computation stage that receives as inputs individual bit values of bit positions within first and second operands and logically combines the individual bit values. The single computation stage outputs, for each bit position, propagate, generate, and kill signals that collectively indicate values for the less than, greater than, and equal to condition code bits. One or more merging stages coupled to the computation stage then merge the propagate, generate, and kill signals into output signals that set the condition code bits.

Abstract: A floating point unit capable of executing multiple instructions in a single clock cycle using a central window and a register map is disclosed. The floating point unit comprises: a plurality of translation units, a future file, a central window, a plurality of functional units, a result queue, and a plurality of physical registers. The floating point unit receives speculative instructions, decodes them, and then stores them in the central window. Speculative top of stack values are generated for each instruction during decoding. Top of stack relative operands are computed to physical registers using a register map. Register stack exchange operations are performed during decoding. Instructions are then stored in the central window, which selects the oldest stored instructions to be issued to each functional pipeline and issues them. Conversion units convert the instruction's operands to an internal format, and normalization units detect and normalize any denormal operands.

Abstract: Modular, portable data collection terminals are disclosed for use in mixed wireless and hard-wired RF communication networks, wherein various radio transmitter modules and associated antennas may be selectively added to a base terminal unit to solve networking problems associated with specific types of business environments. Modularity exists in both the hardware (splitting data collection and processing control circuitry from radio transitive control circuitry) and software (splitting transceiver-specific, lower level communication protocol from generic, higher level communication protocol). The control circuitry, including associated microprocessors devices, interact to selectively activate communication circuits to perform necessary communication or data processing functions and enter and remain in a power-saving dormant state during other times. To support such dormant or "sleeping" states, a series of communication protocols provide for channel access to the communication network.

Abstract: A system for restraining over-eager boosting of load instructions past store instructions in an out-of-order processor. The system comprises a memory disambiguation buffer for storing load and store instruction addresses and associated data and an instruction scheduling window in operative association with the memory disambiguation buffer. The instruction scheduling window and the memory disambiguation buffer determine load/store dependencies and effectuate replay of the store and load instructions wherein a dependent load instruction has been executed prior to a store instruction. An instruction cache is provided in operative association with the memory disambiguation buffer, together to associate the dependent load instructions with a store instruction such that the store instruction is subsequently executed prior to the dependent load instructions.

Abstract: A computer-implemented apparatus and method for countering attempts of polymorphic viruses to evade detection by emulation-based scanners. Such attempts try to exploit differences between the real and virtual execution of instructions. The invention includes a fault manager (158) integrated into the CPU emulator (154) of a virus scanner software product. Before each instruction is emulated by the CPU emulator (154), the fault manager (158) examines the opcode of the instruction to determine (310) whether a "fault" is triggered. If a fault is triggered, the fault manager (158) saves (314) a state record on a fault stack (162), then interrupts (316) to a corresponding fault handler routine (160). The criteria for triggering a fault and the corresponding fault handler routine (160) may be obtained from an updatable data file (164).

Abstract: A redundant controller employs connection-based messaging to ensure reliability and determinacy in communications. The need to close connections and reopen connections with a backup module when control switches from a primary controller to a secondary controller is eliminated by keeping the secondary controller updated as to the connections that have been opened and having the secondary controller assume the connection identification numbers of the primary controller upon switch-over.

Abstract: An electronic data processing circuit is disclosed having at least an instruction memory, an instruction decoder; and a slot structure. The slot structure is characterized by a plurality of slots. Each slot has at least: (1) an address register (2) a data register, (4) a function register, and (3) a monitoring circuit. Each slot asynchronously performs operations defined by the information content of their respective address register, data register and function register when complete information is present.

Abstract: Circuitry is provided that allows a register without an asynchronous loading capability to be asynchronously loaded. Logic gates are provided before and after the register. The logic gates are driven by an output signal from a storage circuit such as a latch. When the output signal has one value the logic gates act as non-inverting buffers. When the output signal has another value the logic gates act as inverters. The circuitry allows the normal synchronous operations of the register to be maintained. A hazard coverage circuit can be provided to prevent glitches from appearing at the output during asynchronous operations. The logic gates may be formed from exclusive OR gates implemented in programmable logic on a programmable logic device.