International Business Machines Corporation

Ronald S Harter

Gary Douglas Huber

Seungyoon P Song

Jeffrey S Lucash

Arturo Martin-de-Nicolas

Robert J Major

The present invention provides a method and system for using hardware to assist software in emulating the guest instructions. The method and system comprises an emulation assist unit (EAU) which efficiently maps a guest instruction to a unique tag, an index, and an address of the corresponding semantic routine. The index determines where in a cache a plurality of tags are stored. A separate cache within the EAU stores each tag in association with the address the first time the corresponding guest instruction is emulated. Thus, the emulation assist unit also dynamically responds to the set of guest instructions being emulated. The first time a guest instruction is emulated, the EAU determines the address and stores the address in the cache in association with the tag. When the guest instruction is emulated again, the EAU uses the tag to access the stored addresses of the corresponding semantic routine.

Method and system for efficiently mapping guest instruction in an

A CPU initializes pluggable adapters with built-in identity and conditional ROS and complies a Hardware First Level Interrupt Handler (HFLIH) table of identity against status register address and a Software First Level Interrupt Handler (HFLIH) table of identity against on-board system function. It stores the tables with a control module in enabled memory on the keyboard adapter. Conditional ROS is enabled on a given adapter receiving a broadcast of its own identity. Adapter interrupts are ORed. HFLIH is stepped through by the control module to access adapter status sequentially, servicing each adapter in turn from its ROS, using its broadcast identity. The enabled adapter appears as a single entity to the central processor and occupies a single window in the address space which is common to all of the adapters but used by only one at a time. System functions are accessed via HFLIH.

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Austin, TX, United States of America

Ronald S Harter