International Business Machines Corporation

Matthew Evans

David Haikney

Gavin Barraclough

Gisle Dankel

William Owen Lovett

During program code conversion, such as in a dynamic binary translator, automatic code generation provides target codeexecutable by a target processor. Multiple instruction portsdisperse a group of instructions to functional unitsof the processor Disclosed is a mechanism of preparing an instruction groupusing a plurality of poolshaving a hierarchical structure-. Each pool represents a different overlapping subset of the issue ports. Placing an instructioninto a particular poolalso reduces vacancies in any one or more subsidiary pools in the hierarchy. In a preferred embodiment, a counter valueis associated with each poolto track vacancies. A valid instruction groupis formed by picking the placed instructionsfrom the pools. The instruction groups are generated accurately and automatically. Decoding errors and stalls are minimized or completely avoided.

Preparing instruction groups for a processor having multiple issue ports

A translator apparatus is provided with both program code interpreting and translating functionality, where subject program code is interpreted rather than being translated in those situations where interpretation of the subject program code is determined to be more beneficial. The translator applies an interpreting algorithm to determine whether a basic block of subject program code should be interpreted or translated. A particular subject of instructions supported by the interpreter functionality is initially selected from an entire instruction set for the subject program code. A basic block will be interpreted 1) if all of the instructions within a basic block are determined to be within the subset of instructions supported by the interpreter functionality, and 2) if an execution count of the basic block is below a translation threshold. If either of these two conditions are not satisfied, then the basic block is translated by the translator

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Manchester, United Kingdom

Matthew Evans