Abstract: A system and method for monitoring usage of peripheral devices and placing a second peripheral device in a low power state when the usage indicates that a second peripheral device is not being used. For example, if a computer system detects that a user's current typing rate indicates the user probably has both hands on a keyboard, the computer system may generate a signal to the computer mouse to enter a low power state. The computer system may use prior usage for a user to determine when current usage indicates that the second peripheral device is not being used. After the second peripheral device is placed in a low power state, the computer system may generate a signal to the second peripheral device to return to a normal power state when the computer system determines that the user no longer has both hands occupied.

Abstract: A method and apparatus for configuration control and power management through special signaling is provided. In one embodiment, a computer system may include a processor and a plurality of devices that may act as a source device, a destination device, or both. A particular source device may be configured for communications with a destination device. The source device may further be configured to violate one or more known communications rules when communicating the with the destination device. The destination device may be configured to detect the violation. The violation of a known communications rule by the source device may indicate a pending change of state in the computer system, or that a change of state has occurred.

Abstract: A dedicated bus between a central processing unit and a peripheral unit, such as a graphics controller driving a video display, provides enhanced capability in an environment in which signal processing occurs within the central processing unit. The dedicated bus relieves other data buses, such as the PCI bus, of the need to communicate large amounts of data, such as decompressed video data. The resulting system supports high bandwidth transmissions of decompressed video data, enabling high resolution 24 bit full motion video and multiple data stream video.

Abstract: An electronic system and method are presented for the implementation of functional redundancy checking (FRC) by comparing “signatures” produced by two different electronic devices, for example central processing units (CPUs). The signatures include a relatively small number of signals which reflect an internal state of each CPU. The electronic system includes a first and second CPU. Each CPU is configured to execute instructions and produce output signals. The first and second CPUs are preferably identical and execute instructions simultaneously such that their internal states and produced output signals should be the same at any given time. Each CPU includes a signature generator for generating the signature. The electronic system also includes a compare unit coupled to receive the signatures. The compare unit compares the signatures and produces an error signal if the signatures are not identical. The electronic system may be a computer system, further including a system bus and chip set logic.

Abstract: A dedicated bus between a central processing unit and a peripheral unit, such as a graphics controller driving a video display, provides enhanced capability in an environment in which signal processing occurs within the central processing unit. The dedicated bus relieves other data buses, such as the PCI bus, of the need to communicate large amounts of data, such as decompressed video data. The resulting system supports high bandwidth transmissions of decompressed video data, enabling high resolution 24 bit full motion video and multiple data stream video.

Abstract: A dedicated bus between a central processing unit and a peripheral unit, such as a graphics controller driving a video display, provides enhanced capability in an environment in which signal processing occurs within the central processing unit. The dedicated bus relieves other data buses, such as the PCI bus, of the need to communicate large amounts of data, such as decompressed video data. The resulting system supports high bandwidth transmissions of decompressed video data, enabling high resolution 24 bit full motion video and multiple data stream video.

Abstract: A computer system optimized for real-time applications which provides increased performance over current computer architectures. The system includes a standard local system bus or expansion bus, such as the PCI bus, and may also include a dedicated real-time bus or multimedia bus. Various multimedia devices are coupled to one or more of the expansion bus and/or the multimedia bus. The computer system includes byte slicing and/or data packing logic coupled to one or more of the expansion bus and/or the multimedia bus which operates to allow different data streams to use different byte channels simultaneously. Thus the byte sliced bus allows different peripherals to share the bus simultaneously. The byte slicing logic thus may assign one data stream to a subset of the total byte lanes on the multimedia bus, and fill the unused byte lanes with another data stream. The data packing logic may optimally fill the bus with data having more or fewer bits than the bus.

Abstract: A computer system optimized for real-time applications which provides increased performance over current computer architectures. The system includes a standard local system bus or expansion bus, such as the PCI bus, and may also include a dedicated real-time bus or multimedia bus. Various multimedia devices are coupled to one or more of the expansion bus and/or the multimedia bus. The computer system includes byte slicing logic coupled to one or more of the expansion bus and/or the multimedia bus which operates to allow different data streams to use different byte channels simultaneously. Thus the byte sliced multimedia bus allows different peripherals to share the bus simultaneously. The byte slicing logic thus may assign one data stream to a subset of the total byte lanes on the multimedia bus, and fill the unused byte lanes with another data stream. The computer system of the present invention thus provides much greater performance for real-time applications than prior systems.

Abstract: A microprocessor including a context file configured to store multiple contexts is provided. The microprocessor may execute multiple threads, each thread having its own context within the microprocessor. In one embodiment, the present microprocessor is capable of executing at least two threads concurrently: a task and an interrupt service routine. Interrupt service routines may be executed without disturbing a task's context and without performing a context save operation. Instead, the interrupt service routine accesses a context which is independent of the context of the task. In another embodiment, the context file includes multiple interrupt service routine contexts. Multiple ISR context storages allow for nested interrupts to be performed concurrently. In yet another embodiment, the microprocessor is configured to execute multiple tasks and multiple interrupt service routines concurrently.

Abstract: An improved programmable interrupt controller for use in a computer system including one or more interrupt service providers (ISPs), usually central processing units (CPUs). At least one CPU and a main memory system are coupled to a host bus. A bus bridge device couples the host bus to the expansion bus. At least one I/O device is coupled to the expansion bus and generates an interrupt request signal. The bus bridge and other bus devices may also generate interrupt request signals. A programmable interrupt controller receives the interrupt requests and provides processor interrupt signals as well as information regarding resource requirements necessary for servicing the interrupts to the one or more CPUs. The programmable interrupt controller also receives interrupt acknowledge signals from the one or more CPUs.

Abstract: A data bus for connecting information processing devices is configurable into a plurality of subbusses in order to fully utilize the data bus capacity. The size and data transfer direction of each subbus, as well as the data transfer speed of each subbus, is independent of the other subbusses. Also, the data bus can be reconfigured to meet changing system requirements. A data bus controller is thus provided to accomplish this data bus reconfiguration. The reconfiguration may be accomplished in accordance with one of a plurality of information flow templates which may be stored in a memory. A method of configuring a data bus is also provided wherein information transfer needs of a system are identified and the data bus is configured according to the identified information transfer means. The reconfiguration in accordance with the information transfer needs may be accomplished in accordance with one or more information flow templates which may be stored in a memory.

Abstract: A microprocessor is provided which is configured to detect the presence of segment override prefixes in instruction code sequences being executed in flat memory mode, and to use the prefix value or the value stored in the associated segment register to control the selection of a bank of registers to use for the instruction operands. Each bank of registers includes the full complement of AMD 80x86 Series registers. Additional registers are available to a program other than the AMD 80x86 Series architecture specifies, but the instruction encoding is unchanged. Having more registers available to a program allows for more operands to be stored in the registers. Since registers are accessible in a shorter period of time than memory, operand access time is decreased.

Abstract: A microprocessor is provided including a branch prediction unit configured to select one of multiple sets of condition flags for use by a branch instruction according to the segment register override prefix byte which may be included with the instruction. Branch instructions may be scheduled distant from the instruction which sets the condition flags tested by the branch instruction. Numerous instructions may be placed between the two instructions, such that the condition flags may be available at the time the instruction is fetched. The branch instruction may be executed without stalling until the condition flags are available. In another embodiment, the branch prediction unit is configured to predict the direction a branch instruction may take according to a branch prediction scheme. Additionally, upon detection of a segment override prefix byte, the branch prediction unit uses an alternative branch prediction scheme.

Abstract: A computer system includes a bus arbiter for controlling the ownership of a bus to which a variety of both real time and non-real time resources are coupled. The bus arbiter includes a request detection unit for detecting bus request signals of a plurality of bus masters, and a grant generator for generating corresponding grant signals to indicate a grant of ownership of the bus. A set of programmable registers are provided to receive configuration information for controlling the relative priority given to each of the bus masters when bus request contention occurs. One or more of the bus masters is configured to generate a grading signal following a particular bus transaction to indicate whether the latency in obtaining the bus during the previous bus request phase was generous, was acceptable, or was longer than desired (i.e., the latency requirement for the device was either violated or reached a critical or near-critical point).

Abstract: A computer system includes a bus arbiter for controlling the ownership of a bus to which a variety of both real time and non-real time resources are coupled. The bus arbiter includes a request detection unit for detecting bus request signals of a plurality of bus masters, and a grant generator for generating corresponding grant signals to indicate a grant of ownership of the bus. A set of programmable registers are provided to receive configuration information for controlling the relative priority given to each of the bus masters when bus request contention occurs. One or more of the bus masters includes an arbitration feedback control circuit and feedback register for generating and storing a value to indicate whether the latency in obtaining the bus during a previous bus request phase was generous, was acceptable, or was longer than desired (i.e., the latency requirement for the device was either violated or the latency in obtaining the bus reached a near-critical point).

Abstract: A microprocessor is provided which is configured to detect the presence of segment override prefixes in instruction code sequences being executed in flat memory mode, and to use the prefix value or the value stored in the associated segment register to selectively enable condition flag modification for instructions. An instruction which modifies the condition flags and a branch instruction intended to branch based on the condition flags set by the instruction may be separated by numerous instructions which do not modify the condition flags. When the branch instruction is decoded, the condition flags it depends on may already be available. In another embodiment of the present microprocessor, the segment register override bytes are used to select between multiple sets of condition flags. Multiple conditions may be retained by the microprocessor for later examination. Conditions which a program utilizes multiple times in a program may be maintained while other conditions may be generated and utilized.

Abstract: An improved bus arbitration system comprising an information bus, first and second bus masters connected to the bus and a bus arbiter for controlling ownership of the bus. The first bus master is adapted to perform speculative pre-fetching and has a first REQ signal for requesting ownership of the bus and an SP signal for indicating when a bus ownership request is for a speculative pre-fetch. The second bus master has a second REQ signal for requesting ownership of the bus. The bus arbiter is configured such that when the first bus master asserts its REQ signal and its SP signal and the second bus master asserts its REQ signal, the bus arbiter assigns higher priority to the second bus master in response to the SP signal.

Abstract: A method and apparatus for transferring original data which includes images, between two stations located a distance apart, without actual transmission of the image portion of the data. A library of images are provided at each of the stations. The image to be transferred is processed into a description of the image which allows the reproduction of the image at the receiving end of the transmission using the images contained in the image library in the receiving station.

Abstract: A method of allocating bandwidth among a plurality of devices communicatively connected through a data bus provides for determining a data need of at least one of the plurality of devices, allocating portions of the data bus to the devices in response to the data need, and transmitting data between the devices on the allocated portions of the data bus. The portions of the data bus can be subbusses, each comprising at least one bit line. The data need can be based on a measure of fullness of a buffer corresponding to the at least one device. The data need can be provided as feedback from the buffer to a data bus controller which allocates the portions of the data bus. The method can use rules for assigning the subbusses which are stored in a memory. A processor can change the rules to accommodate changing conditions in the data bus.

Abstract: A microprocessor is provided which expands the functionality and/or performance of the implemented architecture in transparent and/or non-transparent ways. The microprocessor is configured to detect the presence of segment override prefixes in instruction code sequences being executed in flat memory mode and to use the prefix value to control internal and/or external functions. Additionally, the microprocessor may be configured to signal a change or modification of the normal execution of the instruction(s) which follow. Many embodiments are shown which use the segment override prefixes to expand the performance or capability of the microprocessor. Backward compatibility with older implementations of the x86 architecture may be maintained when implementing transparent embodiments.