Abstract: A microprocessor includes two or more processing cores each configured to determine, at each of succeeding instances in time, an amount of energy consumed by the microprocessor during a period preceding the instance in time. The period is predetermined. Each core also operates at a frequency above a predetermined frequency in response to determining the amount of energy consumed is less than a predetermined amount of energy. All of the cores may operate above the predetermined frequency simultaneously until one of the cores determines the microprocessor has consumed more than the predetermined amount of energy during the period preceding the instance in time. The predetermined frequency may be: a frequency at which all the cores can operate over the predetermined period without the microprocessor consuming more than the predetermined amount of energy, or alternatively the maximum frequency at which system software may request the cores to operate.

Abstract: A microprocessor includes an input that receives an indication of the amount of instantaneous power being supplied to the microprocessor by an external power source. The microprocessor includes a plurality of processing cores that each receive the indication from the input and responsively determine an amount of energy consumed by the microprocessor during a preceding period. The period is a predetermined length of time. Each processing core operates at a frequency above a predetermined frequency in response to determining that the amount of energy consumed by the microprocessor during the preceding period is less than a predetermined amount of energy. The predetermined frequency may be: a frequency at which all the cores can operate over the predetermined length of time without the microprocessor consuming more than the predetermined amount of energy, or alternatively the maximum frequency at which system software may request the two or more processing cores to operate.

Abstract: A microprocessor includes two or more processing cores each configured to compute a first value in response to detecting a power event. The first value represents an amount of energy the core consumed during a time interval leading up to the event. The length of the time interval is predetermined. Each core reads from the memory one or more second values that represent an amount of energy the other cores consume during approximately the time interval. The second values were previously computed and written to the memory by the other cores. Each core adjusts its operating frequency based on the first and second values. The predetermined frequency may be: a frequency at which all the cores can operate over the predetermined length of time without the microprocessor consuming more than the predetermined amount of energy, or alternatively the maximum frequency at which system software may request the cores to operate.

Abstract: A multi-core/multi-package bus termination apparatus includes a configuration array and a plurality of drivers. The configuration array generates location/protocol signals that each direct one of the plurality of drivers on the bus to employ location-based bus termination or protocol-based bus termination. The plurality of drivers is coupled to the plurality of location/protocol signals, a plurality of location signals, a bus ownership signal, and a multi-package signal. Each of the plurality of drivers controls how one of a plurality of nodes is driven responsive to a first state of one of the plurality of location/protocol signals.

Abstract: A microprocessor includes a bus interface unit that interfaces the microprocessor to a bus that includes a signal that, when asserted, instructs all bus agents to refrain from initiating bus transactions. Microcode causes the bus interface unit to assert the signal in response to detecting an event and resets the microprocessor, but does not reset a portion of the bus interface unit that asserts the signal on the bus. After the reset, the microcode causes the bus interface unit to deassert the signal on the bus. Additionally, the microcode sets a flag and saves the microprocessor state to memory before resetting itself, but does not reset the interrupt controller. After the reset, the microcode reloads the state of the microprocessor from the memory. However, if the microcode determines that the flag is set, it forgoes reloading the state of the interrupt controller.

Abstract: A method for debugging a multi-core microprocessor includes causing the microprocessor to perform an actual execution of instructions and obtaining from the microprocessor heartbeat information that specifies an actual execution sequence of the instructions by the plurality of cores relative to one another, commanding a corresponding plurality of instances of a software functional model of the cores to execute the instructions according to the actual execution sequence specified by the heartbeat information to generate simulated results of the execution of the instructions, and comparing the simulated results with actual results of the execution of the instructions to determine whether they match. Each core outputs an instruction execution indicator indicating the number of instructions executed by the core each core clock. A heartbeat generator generates a heartbeat indicator for each core on an external bus that indicates the number of instructions executed by each core during each external bus clock cycle.

Abstract: A microprocessor according to one embodiment includes a supply node providing a core voltage, a functional block, a charge node, select logic, and substrate bias logic. The functional block has multiple power modes and includes one or more semiconductor devices and a substrate bias rail routed within the functional block and coupled to a substrate connection of at least one semiconductor device. The select logic couples the substrate bias rail to the charge node when the functional block is in a low power mode and clamps the substrate bias rail to the supply node when the functional block is in a full power mode. The substrate bias logic charges the charge node to a bias voltage at an offset voltage relative to the core voltage when the functional block is in the low power mode. Semiconductor devices may be provided to clamp or otherwise couple the bias rail.

Abstract: A microprocessor is configured to communicate with other agents on a system bus and includes a cache memory and a bus interface unit coupled to the cache memory and to the system bus. The bus interface unit receives from another agent coupled to the system bus a transaction to read data from a memory address, determines whether the cache memory is holding the data at the memory address in an exclusive state (or a shared state in certain configurations), and asserts a hit-modified signal on the system bus and provides the data on the system bus to the other agent when the cache memory is holding the data at the memory address in an exclusive state. Thus, the delay of an access to the system memory by the other agent is avoided.

Abstract: A microprocessor including a substrate bias rail providing a bias voltage during a first operating mode, a supply node providing a core voltage, a clamp device coupled between the bias rail and the supply node, and control logic. The control logic turns on the clamp device to clamp the bias rail to the supply node during a second operating mode and turns off the clamp device during the first operating mode. The clamp devices may be implemented with P-channel and N-channel devices. Level shift and buffer circuits may be provided to control the clamp devices based on substrate bias voltage levels. The microprocessor may include a substrate with first and second areas each including separate substrate bias rails. The control logic separately turns on and off clamp devices to selectively clamp the substrate bias rails in the first and second areas based on various power modes.

Abstract: An apparatus for locking out a source synchronous strobe receiver, including a delay-locked loop (DLL) and receivers. The DLL receives a reference clock, and generates a select vector and an encoded select vector. The select vector is employed to select a delayed version of the reference clock that lags the reference clock by a prescribed number of cycles. The select vector is reduced by an amount and is gray encoded to indicate the lockout time. The receivers are each coupled to the delay-locked loop. Each of the receivers receives the encoded select vector and a corresponding strobe, and locks out reception of the corresponding strobe for the lockout time following transition of the corresponding strobe. The encoded select vector is employed by a gray code mux therein to determine the lockout time by selecting a delayed version of the corresponding strobe.

Abstract: A microprocessor includes a first plurality of fuses, a predetermined number of which are selectively blown. Control values are provided from the fuses to circuits of the microprocessor to control operation thereof. A second plurality of fuses are blown with the predetermined number of the first plurality of fuses that are blown and a Boolean complement of the predetermined number. In response to being reset, the microprocessor: reads the predetermined number and the Boolean complement of the predetermined number from the second plurality of fuses, Boolean complements the predetermined number read from the second plurality of fuses to generate a result, compares the result with the Boolean complement of the predetermined number read from the second plurality of fuses, and prevent itself from fetching and executing user program instructions if the result does not equal the Boolean complement of the predetermined number read from the second plurality of fuses.

Abstract: A microprocessor includes a first plurality of fuses, a predetermined number of which are selectively blown. Control values are provided from the first plurality of fuses to circuits of the microprocessor to control operation of the microprocessor. The microprocessor also includes a second plurality of fuses, blown with the predetermined number of the first plurality of fuses that are blown. In response to being reset, the microprocessor is configured to: read the first plurality of fuses and count a number of them that are blown; read the predetermined number from the second plurality of fuses; compare the counted number with the predetermined number read from the second plurality of fuses; and prevent itself from fetching and executing user program instructions if the number counted from reading the first plurality of fuses does not equal the predetermined number read from the second plurality of fuses.

Abstract: A microprocessor including a temperature sensor that monitors a temperature of core logic of the microprocessor during operation thereof, and operating point information from which may be determined N operating points at which the microprocessor core may reliably operate at a first temperature. Each of the N operating points has a different combination of operating frequency and voltage. The N operating points comprise a highest operating point, a lowest operating point, and a plurality of operating points intermediate the highest and lowest operating points. The microprocessor also includes a control circuit that transitions operation of the core logic among the N operating points to attempt to keep the operating temperature of the core logic provided by the temperature sensor within a temperature range whose upper bound is the first temperature.

Abstract: A multi-core bus termination apparatus includes a protocol analyzer and a plurality of drivers. The protocol analyzer is disposed within a processor core and configured to receive one or more protocol signals, and is configured to indicate whether or not the processor core owns the bus. The plurality of drivers is coupled to the protocol analyzer. Each of the plurality of drivers has one of a corresponding plurality of nodes, and each is configured to control how the one of the corresponding plurality of nodes is driven responsive whether or not the processor core owns the bus. Each of the plurality of drivers has protocol-based multi-core logic. The protocol-based multi-core logic is configured to enable pull-up logic if the processor core owns the bus, and is configured to disable the pull-up logic if the processor core does not own the bus.

Abstract: A multi-core/multi-package bus termination apparatus includes a configuration array and a plurality of drivers. The configuration array generates location/protocol signals that each direct one of the plurality of drivers on the bus to employ location-based bus termination or protocol-based bus termination. The plurality of drivers is coupled to the plurality of location/protocol signals, a plurality of location signals, a bus ownership signal, and a multi-package signal. Each of the plurality of drivers controls how one of a plurality of nodes is driven responsive to a first state of one of the plurality of location/protocol signals.

Abstract: A multi-core bus termination apparatus includes a location array and a plurality of drivers. The location array generates a plurality of location signals that indicate locations on the bus of a corresponding plurality of nodes that are coupled to the bus, where the locations comprise either an internal location or a bus end location. Each of the plurality of drivers has one of the corresponding plurality of nodes, and controls how the one of the corresponding plurality of nodes is driven responsive to a state of a corresponding one of the plurality of location signals. Each of the plurality of drivers has configurable multi-core logic. The configurable multi-core logic enables pull-up logic and first pull-down logic if the state indicates the bus end location. The configurable multi-core logic disables the pull-up logic and to enable the first pull-down logic and second pull-down logic if the state indicates the internal location.

Abstract: A multi-core bus termination apparatus includes a protocol analyzer and a plurality of drivers. The protocol analyzer is disposed within a processor core and configured to receive one or more protocol signals, and is configured to indicate whether or not the processor core owns the bus. The plurality of drivers is coupled to the protocol analyzer. Each of the plurality of drivers has one of a corresponding plurality of nodes, and each is configured to control how the one of the corresponding plurality of nodes is driven responsive whether or not the processor core owns the bus. Each of the plurality of drivers has protocol-based multi-core logic. The protocol-based multi-core logic is configured to enable pull-up logic if the processor core owns the bus, and is configured to disable the pull-up logic if the processor core does not own the bus.

Abstract: A microprocessor control circuit continuously monitors core logic operating temperature and detects it has risen above a first temperature and responsively iteratively controls a system voltage source to output a next lower one of its N output voltage levels and controls clock generation circuitry of the microprocessor to output a lower one of its M core clock signal frequencies as necessitated by a transition to the next lower output voltage level until the temperature drops below the first temperature. The control circuit detects that the temperature has dropped below a second temperature and responsively iteratively controls the voltage source to output a next higher output voltage level and controls the clock generation circuitry to output a higher core clock signal frequency as permitted by the next higher output voltage level until the operating temperature rises above the second temperature. The M frequencies comprise a highest, lowest, and plurality of intermediate frequencies.

Abstract: A microprocessor that performs adaptive power throttling includes a calculation unit that calculates an average power consumed by the microprocessor over a most recent predetermined sample time and determines whether the average power is less than a predetermined maximum power value. A power management unit controls the microprocessor to conditionally operate at a predetermined frequency if the average power is less than the predetermined maximum power value. The predetermined frequency is a frequency at which the microprocessor may consume more than the predetermined maximum power value. The predetermined maximum power value and sample time are specified to achieve power and/or thermal design goals of a system in which the microprocessor operates. The predetermined maximum power and/or sample time values are programmable by system software.

Abstract: A temperature sensor in a microprocessor monitors its operating temperature Operating point data includes a first temperature being the maximum temperature at which the microprocessor will reliably operate at a first frequency and first voltage, the first frequency being the maximum frequency at which the microprocessor will reliably operate at the first temperature and the first voltage. Operating point data also includes a second temperature at which the microprocessor will reliably operate at a second frequency and a second voltage, the second frequency being greater than the first frequency and the second temperature less than the first temperature. A control circuit causes the microprocessor to operate at the second voltage and frequency rather than the first voltage and frequency in response to detecting that while operating at the first voltage and the first frequency the operating temperature dropped below the second temperature.