Abstract: An interrupt controller includes an interrupt request register for receiving interrupt requests from various peripherals or I/O devices via a set of request lines. A priority resolver is further provided for comparing the priority level of the interrupt lines, latching the lower priority requests in a stand-by mode, and directing servicing of the highest priority level. An in-service register is provided for storing the identification of any request line that is being serviced by the microprocessor. In one embodiment, a set of signal lines are coupled between the in-service register and external terminals of the integrated circuit on which the interrupt controller is fabricated. A power management unit may be coupled to the external pins of the integrated circuit and thereby receives real-time information regarding an interrupt request that is currently being serviced and regarding interrupt service routines that have completed.

Abstract: A system and method for providing information regarding system support capabilities to a processor. A computer system includes a processing unit, a main memory and a first plurality of peripherals coupled to a first bus. A bus bridge couples the first bus to a second bus and a second plurality of support peripherals are coupled to the second bus. The processing unit is capable of providing requests for system support information to the bus bridge and the first and second plurality support peripherals. The peripherals are configured to provide responses to the request. The processing unit stores the responses and uses the information received to enable and disable its functional units or the peripheral's functional units accordingly. In one embodiment, the requests and information are provided along a dedicated serial interface. In another, the requests and information are provided as specialized bus cycles along the CPU bus.

Abstract: A method and apparatus for software to access a microprocessor serial number. Provision of the serial number allows the manufacturer better control over its product and also permits software vendors to register their products. The serial number is encrypted using a pair of encryption keys to prevent unauthorized changes. At least one of the encryption keys is itself encoded to prevent unauthorized access, while permitting software to access the serial number.

Abstract: A method and apparatus for providing, maintaining and upgrading the software lock of a microprocessor. When a processor upgrade occurs, software that was serialized to the previously installed processor detects that it is running on an unauthorized processor. The software initiates a reauthorization process based on a reauthorization use profile. The temporary re-enabling of the software is allowed if the authorization service is not available.

Abstract: A variety of clock intensive functions, such as interval timers, real-time clocks, and resettable timers for triggering watchdog reset and power management mode transitions, are provided using a single counter and timer event control logic. Such an integrated timer provides multiple time-based event signals from a single sequence of states. The integrated timer circuit includes sequential logic with a plurality of bit outputs, first and second configuration registers, and timer event control logic. The sequential logic supplies a sequence of states at the bit outputs in response to a clock signal. Variations of the sequential logic include a free-running binary counter, ripple counter, or gray code counter. State detection logic is coupled to the bit outputs of the sequential logic and coupled to the first and second configuration registers to receive first and second event descriptors.

Abstract: A method and apparatus for encrypting and decrypting a microprocessor serial number. First and second encryption keys and a serial number are provided in microprocessor machine specific registers. The serial number is encrypted using the first key. The encrypted serial number is encrypted using the second key. The first encryption key may be encrypted along with the serial number using the second key. The double encrypted serial number is then stored in memory provided for that purpose.

Abstract: A non-volatile memory chip enable encoding method allows the storage of both boot code and user application software within a common memory array. The chip enable encoding method further allows a variable number of memory banks to be provided within the non-volatile memory array and allows the system to power-up and execute the boot code before the array configurations are selected by firmware. In one embodiment, a memory controller includes four chip enable output lines for selectively enabling a plurality of ROM banks. One of the ROM banks includes boot code that is executed by the system microprocessor during system boot. If the user requires a ROM array consisting of four ROM banks, a separate chip enable output line is connected to each ROM bank. If the user instead requires a ROM array consisting of, for example, eight ROM banks, an external decoder may be connected to the four chip enable output lines.

Abstract: An interrupt controller includes an interrupt request register for receiving interrupt requests from various peripherals or I/O devices via a set of request lines. A priority resolver is further provided for comparing the priority level of the interrupt lines, latching the lower priority requests in a stand-by mode, and directing servicing of the highest priority level. An in-service register is provided for storing the identification of any request line that is being serviced by the microprocessor. In one embodiment, a set of signal lines are coupled between the in-service register and external terminals of the integrated circuit on which the interrupt controller is fabricated. A power management unit may be coupled to the external pins of the integrated circuit and thereby receives real-time information regarding an interrupt request that is currently being serviced and regarding interrupt service routines that have completed.

Abstract: A memory paging and compression system for a computer having a memory and an execution unit includes an address mapping hierarchy, a compressed page mapping hierarchy, a translation lookaside buffer, and a compression/decompression component. The address mapping hierarchy includes page tables having page table entries which map from a first portion of virtual addresses to respective pages in physical memory. The compressed page mapping hierarchy includes compressed page tables having compressed page table entries mapping from the first portion of virtual addresses to respective compressed pages in physical memory. The translation lookaside buffer caches recently used ones of the mappings from the first portion of virtual addresses to respective pages in physical memory.

Abstract: An integrated processor is provided that includes a CPU core coupled to a variety of on-chip peripheral devices such as a DMA controller, an interrupt controller, and a timer. The integrated processor further includes a power management message unit coupled to the DMA controller, interrupt controller, and timer for monitoring the internal interrupt and bus request signals of the integrated processor. The power management message unit may also monitor other selected activities of the integrated processor depending upon the system requirements. Based on the detected activities, if any, the power management message unit encodes a message on a power management message bus to thereby provide information regarding the internal events of the integrated processor to an outside power management unit. The power management message bus is channeled from the integrated processor at a set of package pins that are isolated from the standard external peripheral bus of the integrated processor.

Abstract: A non-volatile memory controller is provided which is connectable directly to the local bus of a computer system and which allows access to one or more 32-bit banks of ROM and to an 8-bit bank of non-volatile memory. The 8-bit bank of non-volatile memory may be used, for example, to store BIOS code, and may be implemented using a ROM or flash memory device. The non-volatile memory controller includes a data router, a sequencer, and a set of output latches for routing the 8-bit BIOS code (stored within the 8-bit bank) to selected byte lanes of the local bus and for converting the 8-bit data to 32-bit local bus data. The non-volatile memory controller further supports high performance, 32-bit accesses to the user software stored within the 32-bit banks. If the system designer or user instead must maximize the memory capacity of the computer system, the 8-bit bank of memory may be replaced with a larger 32-bit bank of memory.

Abstract: A computer system is provided that includes an interrupt driven system management mode during which system management code is accessed. In one embodiment, a lock-out register is provided to prevent accesses to the system management code while the computer system is operating in its normal mode. In one embodiment, an interrupt control unit is coupled to the ICE interrupt line of the microprocessor core, and controls a memory control unit in accordance with assertions of an external "debug" interrupt signal and an external SMM (system management mode) interrupt signal. If the debug interrupt signal is asserted while the microprocessor core is operating in its normal mode, the interrupt control unit responsively asserts the ICE interrupt signal to the microprocessor core, thereby, causing the microprocessor core to execute ICE code.

Abstract: A system and method for controlling a peripheral bus clock signal through a slave device are provided that accommodate a power conservation scheme in which a peripheral bus clock signal may be stopped, for example, by a power management unit or other central resource. Prior to stopping the peripheral bus clock signal, an indicator signal is generated at a clock request line by a clock control circuit. If the slave device continues to require the peripheral bus clock signal, the slave device responsively generates a clock request signal. The clock control circuit receives the clock request signal and accordingly prevents the peripheral bus clock signal from stopping. The system may further allow an alternate bus master to assert the clock request signal to re-start the peripheral bus clock signal after it has stopped. The alternate bus master can thereby generate a synchronous bus request signal to attain mastership of the peripheral bus.

Abstract: A direct memory access controller is provided that performs DMA transfers by executing both a memory access cycle and an I/O access cycle. During the memory access cycle, the address location of system memory to be accessed is driven on the addressing lines of a local bus. During the I/O access cycle, an address value within a DMA configuration address range is driven on the address lines of the local bus. The DMA configuration address range is the range of address values to which the configuration registers of the DMA controller are mapped for receiving initialization data. Accordingly, other peripheral devices that may be connected to the local bus will not respond to the I/O access cycle. An address disable signal is further not required to disable the address decoders of other I/O peripheral devices not involved in the DMA transfer.

Abstract: A direct memory access controller implements a two-cycle approach for performing a desired DMA transfer by executing both a memory access cycle and an I/O access cycle. During the memory access cycle, the address location of system memory to be accessed is driven on the addressing lines of a local bus. During the I/O access cycle, an address value within a DMA configuration address range is driven on the address lines of the local bus. The lower two order bits of the address value are encoded to provide byte lane information to a peripheral device during the I.backslash.O access cycle. The peripheral device responsively receives or provides data at the specified byte lane. As a result, peripheral devices that may be connected to the local bus will not respond to the I/O access cycle, while encoded byte lane information is provided to the desired peripheral device without requiring dedicated byte select lines.

Abstract: An integrated processor that employs a bus interface unit to accommodate high performance data transfers via an external peripheral interconnect bus with multiplexed address/data lines. The peripheral interconnect bus, which may be a PCI standard bus, accommodates data transfers between an internal bus of the integrated processor and PCI peripheral devices. The integrated processor further includes a sub-bus control unit that generates a set of side-band control signals that allow the external derivation of a lower performance secondary bus, such as an ISA bus, without requiring a complete set of external pins for the secondary bus on the integrated processor. The derivation of the secondary bus is accomplished with an external data buffer and an external address latch which are controlled by the side-band control signals. Separate address and data lines from the integrated processor for the secondary bus are not required.

Abstract: An integrated processor is provided that includes a CPU core coupled to a variety of on-chip peripheral devices such as a DMA controller, an interrupt controller, and a timer. The integrated processor further includes a power management message unit coupled to the DMA controller, interrupt controller, and timer for monitoring the internal interrupt and bus request signals of the integrated processor. The power management message unit may also monitor other selected activities of the integrated processor such as activities of a floating-point coprocessing subunit. Based on the detected activities, if any, the power management message unit encodes a message on a power management message bus to thereby provide information regarding the internal events of the integrated processor to an external power management unit. Power management decisions are made by an external power management unit.

Abstract: The invention relates to a clock controller circuit for performing a power saving feature in high performance microprocessors. The invention utilizes two logic gates and a flip flop for disabling a clock signal to an execution unit or ALU when data is not available for the execution unit or ALU. The invention provides a sleep mode or clock idle mode for an execution unit when data is not available for the execution unit because memory units, I/O devices, or internal caches are unable to provide data or instructions to the execution unit. The clock controller circuit disables the clock signals by gating the clock signal to a logic high. The clock controller circuit stops the clock signals in response to a no data available signal from a bus unit and a data required signal from the execution unit.

Abstract: An integrated digital processing apparatus for use in a computing device. The apparatus comprises a central processor for effecting processing functions according to a program, a plurality of bus-accommodating devices for accommodating direct operative connection of peripheral devices via a plurality of buses, a single internal bus for accommodating communications internal of the apparatus among the central processing unit and the plurality of bus-accommodating devices, and an internal bus control for controlling utilization of the internal bus. The apparatus is, preferably, configured as an integrated digital circuit on a single substrate.

Abstract: An address manager, for use in a memory management system, translates a multiple-bit memory address received from a central processing unit and provides a translated memory address to a memory control unit. The address manager includes an address translation unit including a translation look-up table which translates the memory address to a translated address in accordance with translation parameters stored in the look-up table, and a translation unit control register which provides the address translation unit look-up table with the translation parameters. The address translation unit also includes an alert signal generator which provides the memory control unit with an alert signal when an address is being translated. The central processing unit, the address translation unit, the translation unit control register and the memory control unit are all integrated within a single integrated circuit.