Abstract: A plurality of Guest cells of Guest instructions are provided with corresponding Host cells for emulating Guest instructions, each Guest instruction having a Guest cell corresponding to a Host cell. Each of the Host cells are initialized with an initialization routine for discovering a corresponding semantic routine for emulating the Guest instruction. When an instruction is to be emulated for the first time, the initialization routine patches itself with the discovered semantic routine such that subsequent emulation of the Guest instruction can be directly performed.

Abstract: A disjoint instruction for accessing operands in memory while executing in a processor of a plurality of processes interrogates a state indicator settable by other processors to determine if the disjoint instruction accessed the operands without an intervening store operation from another processor to the operand. A condition code is set based on the state indicator.

Abstract: Dynamic creation of a spatially aware emulation environment comprising Host cells of Host pages corresponding to Guest cells of Guest pages of Guest instructions. Each Host cell comprises a semantic routine for emulating a corresponding Guest instruction located at the corresponding Guest cell of the guest page.

Abstract: Native code corresponding to an invalidated trace is re-used in a system emulator. A first trace is identified. A dropped second trace is identified. The dropped second trace is associated with a first native code for emulating the second trace. If the identified first trace corresponds to the dropped second trace, the first native code is associated to the first trace, and the first native code is executed. If the identified first trace does not correspond to the dropped second trace, a second native code for emulating the first trace is created, the second native code is associated with the first trace, and the second native code is executed.

Abstract: A instructions of a Guest program to be emulated by a Host computer occupy one or more Guest cells of Guest memory, each Guest cell having a corresponding Host cell in Host memory. The emulator selects a Host cell for emulating a Guest instruction. When the Host cell corresponds to a Guest cell other than a cell aligned with the beginning of the Guest instruction, a wild branch handling routine is executed.

Abstract: A disjoint instruction for accessing operands in memory while executing in a processor of a plurality of processes interrogates a state indicator settable by other processors to determine if the disjoint instruction accessed the operands without an intervening store operation from another processor to the operand. A condition code is set based on the state indicator.

Abstract: A selected group of Guest machine instructions in an emulation environment are translated to a semantic routine of Host machine instructions, wherein Guest cells corresponding to an opcode portion of a Guest instruction are mapped to corresponding Host cells, wherein the semantic routine of Host machine instructions are patched into a Host cell corresponding to the first Guest cell of the group of Guest machine instructions, wherein other Host cells of the corresponding Host cells are patched with semantic routines for emulating single instructions associated with the corresponding Guest cell.

Abstract: A instructions of a Guest program to be emulated by a Host computer occupy one or more Guest cells of Guest memory, each Guest cell having a corresponding Host cell in Host memory. The emulator selects a Host cell for emulating a Guest instruction. When the Host cell corresponds to a Guest cell other than a cell aligned with the beginning of the Guest instruction, a wild branch handling routine is executed.

Abstract: Dynamic creation of a spatially aware emulation environment comprising Host cells of Host pages corresponding to Guest cells of Guest pages of Guest instructions. Each Host cell comprises a semantic routine for emulating a corresponding Guest instruction located at the corresponding Guest cell of the guest page.

Abstract: A plurality of Guest cells of Guest instructions are provided with corresponding Host cells for emulating Guest instructions, each Guest instruction having a Guest cell corresponding to a Host cell. Each of the Host cells are initialized with an initialization routine for discovering a corresponding semantic routine for emulating the Guest instruction.

Abstract: The illustrative embodiments described herein provide a computer-implemented method, apparatus, and computer program product for managing variable assignments in a program. The process identifies a set of variable assignments that is live on a portion of paths to form a set of identified variable assignments. Each of the set of identified variable assignments assign a value to at least one variable of a set of variables. The process determines a set of program points at which the set of identified variable assignments is live on all paths. The process also moves the set of identified variable assignments to the set of program points in response to determining that the set of identified variable assignments is movable to the set of program points.

Abstract: Emulation of source machine instructions is provided in which target machine CPU condition codes are employed to produce emulated condition code settings without the use, encoding or generation of branching instructions.