International Business Machines Corporation

Jason Michael Hopp

Richard Gerard Hofmann

Dennis Charles Wilkerson

Benjamin Herrenschmidt

Kenichi Tsuchiya

Peter Dean LaFauci

Rhonda Gurganious Mitchell

Maciej Piotr Tyrlik

A computer implemented method searches a unified translation lookaside buffer. Responsive to a request to access the unified translation lookaside buffer, a first order code within a first entry of a search priority configuration register is identified. A unified translation lookaside buffer is then searched according to the first order code for a hashed page entry. If the hashed page entry is not found when searching a unified translation lookaside buffer according to the first order code, a second order code is identified within a second entry of the search priority configuration register. The unified translation lookaside buffer is then searched according to the second order code for the hashed page entry.

Software assisted translation lookaside buffer search mechanism

A method and system for forwarding interrupt requests from a source device to a destination device. A controller bridge receives data, from a source device, for a destination device and stores the incoming data in a data queue. An interrupt request is received from the source device for the destination device and forwarded to the destination device in response to completing a transfer of the data from the source device to the destination device. If data received from the source device for the destination device are pending in the data queue, the interrupt request is rejected and the source may resubmit the interrupt request at a later time. If additional data are received from the source device for the destination device, the data may be rejected in response to an interrupt pending in the interrupt queue from the source device for the destination device.

System and method for delaying an interrupt request until corresponding data is provided to a destination device

A multi-master computer system having overlapped read and write signal with scalable address pipelining programmable increases the depth of address pipelining independently on two overlapped read and write data busses up to &ldquo;N&rdquo; deep requests. The system includes a local bus having an address bus, a read bus, and a write bus. Master devices are coupled to separate address, read data and write data buses. Slave devices are attached to the data busses through shared, but decoupled address, read and write data buses. An arbiter is coupled to the data bus and allows masters to compete for bus ownership. The arbiter includes read and write pipeline logic for processing and priortizing master and slave read and write data transfers across the data bus. Programming apparatus alters the read and write pipeline logic for address pipelining

Multi-master computer system with overlapped read and write operations and scalable address pipelining

Disclosed is a method and apparatus for optimizing communication between buses operating at different frequencies. A high speed bus provides communication between high speed devices as well as provides communication to a lower speed bus which provides communications between low speed devices and between low speed devices and high speed devices. During transaction reset a bridge device that controls communication between the high and low speed buses determines the ratio of the respective bus clocks. The bridge device sets a logic state machine based on this data and selects from the higher frequency clock selected cycles on which transfers to the lower speed bus take place. The unused cycles of the high speed clock may then be used on the high speed bus for additional transfers. The clock ratios may be determined on each transaction reset and new data on clock ratios stored in the bridge device for subsequent operation.

Growing community of inventors

Apex, NC, United States of America

Jason Michael Hopp