Hewlett-packard Company

Steven C Boettner

William R Bryg

David V James

William S Worley, Jr

Terrence C Miller

Michael J Mahon

Michael E Gardner

Tso-Kai Liu

Explicit instructions are provided that enable software to directly control insertion of information into a translation lookaside buffer (TLB). A first pair of instructions enable information to be inserted into a data TLB and a second pair of instructions enable information to be inserted into an instruction TLB. In each of these pairs, the first instruction inserts the virtual address and the associated physical address. In response to the second instruction of each of these pairs, additional information about that physical page, such as protection information and flags, is inserted.

Explicit instructions for control of translation lookaside buffers

A virtual memory system is used to control access to I/O device address space in accordance with a preferred embodiment of the present invention. In a virtual memory system, access to pages within a processor's address space are assigned to each application program. Each I/O device is assigned two pages of address space. One page is considered to be privileged, and the other unprivileged. Each I/O device register is associated with an address in each of the two pages of its I/O device address space. Address space is global. What is meant by global is that physical memory locations map to the same virtual memory space regardless of what process is running on the processor. Access codes accompanied by a write disable bit are used to control process access to various addresses.

Direct input/output in a virtual memory system

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San Jose, CA, United States of America

Steven C Boettner