Abstract: Methods, systems and computer program products for dynamically selecting an OSC hazard avoidance mechanism are provided. Aspects include receiving a load instruction that is associated with an operand store compare (OSC) prediction. The OSC prediction is stored in an entry of an OSC history table (OHT) and includes a multiple dependencies indicator (MDI). Responsive to determining the MDI is in a first state, aspects include applying a first OSC hazard avoidance mechanism in relation to the load instruction. Responsive to determining that the load instruction is dependent on more than one store instruction, aspects include placing the MDI in a second state. The MDI being in the second state provides an indication to apply a second OSC hazard avoidance mechanism in relation to the load instruction.

Abstract: Provided are embodiments including a computer-implemented method, system and computer program product for determining precise operand-store-compare (OSC) predictions to avoid false dependencies. Some embodiments include detecting an instruction causing an OSC event, wherein the OSC event is at least one of a store-hit-load event or a load-hit-store event, marking an entry in a queue for the instruction based on the detected OSC event, wherein marking the entry comprises setting a bit and saving a tag in the entry in the queue. Some embodiments also include installing an address for the instruction and the tag in the history table responsive to completing the instruction.

Abstract: Methods, systems and computer program products for heuristically invalidating non-useful entries in an array are provided. Aspects include receiving an instruction that is associated with an operand store compare (OSC) prediction for at least one of a store function and a load function. The OSC prediction is stored in an entry of an OSC history table (OHT). Aspects also include executing the instruction. Responsive to determining, based on the execution of the instruction, that data forwarding did not occur, aspects include incrementing a useless OSC prediction counter. Responsive to determining that the useless OSC prediction counter is equal to a predetermined value, aspects also include invalidating the entry of the OHT associated with the instruction.

Abstract: Examples of techniques for store hit multiple load side register for operand store compare are described herein. An aspect includes, based on detecting a store hit multiple load condition in the processor, updating a register of the processor to hold information corresponding to a first store instruction that triggered the detected store hit multiple load condition. Another aspect includes, based on issuing a second store instruction in the processor, determining whether the second store instruction corresponds to the information in the register. Another aspect includes, based on determining that the second store instruction corresponds to the information in the register, tagging the second store instruction with an operand store compare mark.

Abstract: A computer system includes a branch detection module and a branch predictor module. The branch detection module determines that a first program branch is a possible call branch having a next sequential instruction address (NSIA), and determines that a first routine branch is a possible return capable branch having the first routine instruction address that is a detected as being offset. The branch predictor module determines that a second program branch is a possible call branch having a next sequential instruction address (NSIA), and determines that a second routine branch is a predicted return branch having a predicted target instruction address based on the NSIA of the second program branch and the predicted offset.

Abstract: Examples of techniques for controlling write requests to a memory structure having limited write ports are described herein. An aspect includes storing, in a first queue, write requests received from a first source having a first priority. Another aspect includes storing, in a second queue, write requests received from a second source having a second priority, wherein the second priority is lower than the first priority. Aspects also include identifying a selected queue from the first queue and the second queue based on a selection algorithm, which is a function of a state associated with the first queue and the second queue. Aspects further include forwarding a write request from the selected queue to a write port of the memory structure.

Abstract: A system includes a hierarchical metadata predictor and a processing circuit. The hierarchical metadata predictor includes a first-level metadata predictor and a second-level metadata predictor. The processing circuit is configured to perform a plurality of operations including storing new or updated metadata into the first-level metadata predictor and searching the first-level metadata predictor for a metadata prediction. Responsive to finding the metadata prediction in the first-level metadata predictor, the metadata prediction is output corresponding to an entry of the first-level metadata predictor that is a hit. One or more entries of the first-level metadata predictor that are non-hits are periodically written to the second-level metadata predictor. The first-level metadata predictor is updated based on locating the metadata prediction in the second-level metadata predictor.

Abstract: Aspects include storing a plurality of mappings of logical registers to physical registers in a first structure of a processor. An updated mapping of one or more of the logical registers to the physical registers based on a group of instructions is received. A plurality of allocated register mapping entries associated with the updated mapping of the first structure is split into a first register allocation group and a second register allocation group. A second structure of the processor is updated with the updated mapping of the first register allocation group. A third structure of the processor is updated with the updated mapping of the second register allocation group.

Abstract: A system includes a branch predictor and a processing circuit configured to perform a plurality of operations including storing a skip-over offset value in the branch predictor. The skip-over offset value defines a number of search addresses of the branch predictor to be skipped. The operations further include searching the branch predictor for a branch prediction. Responsive to finding the branch prediction, the searching of the branch predictor is re-indexed based on the skip-over offset value associated with the branch prediction.

Abstract: A motor control system powered by an input power source. The system includes a reactive power reducing input power system in electrical communication with a motor and a constant frequency input power source. The reactive power reducing input power system includes an AC-DC converter and a regulator system, wherein the regulator system is in electrical communication with a DC-AC inverter that is in electrical communication with the motor. The system may include an isolation system to electrically isolate the DC-AC inverter from the motor when the DC-AC inverter is not transmitting power to the motor. The system may accept multiple alternating current voltage sources including both single phase and three phase sources.

Abstract: A motor control system powered by an input power source. The system includes a reactive power reducing input power system in electrical communication with a motor and a constant frequency input power source. The reactive power reducing input power system includes an AC-DC converter and a regulator system, wherein the regulator system is in electrical communication with a DC-AC inverter that is in electrical communication with the motor. The system may include an isolation system to electrically isolate the DC-AC inverter from the motor when the DC-AC inverter is not transmitting power to the motor. The system may accept multiple alternating current voltage sources including both single phase and three phase sources.

Abstract: A suspension work platform hoist system powered by an input power source for raising a work platform on a rope. The system includes a hoist having a motor that drives a traction mechanism designed to cooperate with the rope, and a reactive power reducing input power system in electrical communication with the motor and the constant frequency input power source. The reactive power reducing input power system includes an AC-DC converter and a regulator system, wherein the regulator system is in electrical communication with a DC-AC inverter that is in electrical communication with the motor. The system may include an isolation system to electrically isolate the DC-AC inverter from the motor when the DC-AC inverter is not transmitting power to the motor. The system may accept multiple alternating current voltage sources including both single phase and three phase sources.

Abstract: A suspension work platform hoist system having a variable acceleration motor control system and a tilt control system. The tilt control system includes at least one tilt sensor to sense a tilt angle of the work platform and generate a tilt signal. A tilt controller receives the tilt signal and generates a speed control signal, which is used by the variable acceleration motor control system to control the operation of the hoist motors to maintain a tilt angle setpoint as the work platform is raised and lowered. The tilt control system may include a settling mode having a settling tilt angle setpoint, wherein the settling mode prevents the work platform from being raised or lowered until the tilt angle of the work platform reaches the settling tilt angle setpoint.

Abstract: A suspension work platform hoist system having a variable acceleration motor control system and a tilt control system. The tilt control system includes at least one tilt sensor to sense a tilt angle of the work platform and generate a tilt signal. A tilt controller receives the tilt signal and generates a speed control signal, which is used by the variable acceleration motor control system to control the operation of the hoist motors to maintain a tilt angle setpoint as the work platform is raised and lowered. The tilt control system may include a settling mode having a settling tilt angle setpoint, wherein the settling mode prevents the work platform from being raised or lowered until the tilt angle of the work platform reaches the settling tilt angle setpoint.

Abstract: A suspension work platform hoist system having reduced reactive power to produce a hoist system power factor of at least 0.95 when operating at a steady state full-load condition as the motor raises the work platform. The hoist system power factor takes into account all the power consuming devices of the suspension work platform hoist system as well as a suspended conductor system that connects the constant frequency input power source to the hoist, which is often in excess of several hundred feet. The hoist system power factor may be achieved by incorporating a reactive power reducing input power system into the suspension work platform hoist system. The reactive power reducing input power system decreases the magnitude of the reactive power of the motor producing a high hoist system power. The reactive power reducing input power system may include an AC-DC converter and a regulator system in electrical communication with a DC-AC inverter that is in electrical communication with the motor.

Abstract: A suspension work platform hoist system for raising and lowering a work platform is provided. The system incorporates at least one hoist attached to the work platform and in electrical communication with a motor control system. The motor control system is attached to the work platform and is in electrical communication with a constant frequency input power source and the hoist motor. The motor control system controls the acceleration of the work platform as it is raised and lowered by controlling the hoist motor. The system may further include a tilt control system to allow the work platform to reach and maintain a tilt angle setpoint as the work platform is raised and lowered, and/or a system to reduce the reactive power associated with its operation.

Abstract: A method, apparatus and computer-readable medium for managing portlets and like applications is presented. In one embodiment, the method includes using Unified Modeling Language (UML) code to describe a flow of a User Interface (UI) application, wherein the flow describes transitions of discrete states in the UI application. The UI application may be a Web application, such as a portlet or a servlet. In another embodiment, the method further includes the steps of using UML code to describe a view of discrete states of the UI application, and applying UML stereotypes to create individual views of the discrete states of the UI application.