International Business Machines Corporation

Ali Ijaz Sheikh

Reid T Copeland

Marcel Mitran

Theodore Joseph Bohizic

Carlos D Cavanna

Chad McIntyre

Toshihiko Koju

Kirk A Stewart

Ying Di Zhang

Vijay Sundaresan

Derek Bruce Inglis

Viktor Sandor Gyuris

Michael J Moniz

Srivatsan Vijayakumar

Diana P Sutandie

Maged M Michael

Harold Wade Cain, Iii

Kevin Alexander Stoodley

Motohiro Kawahito

Takuya Nakaike

Andrew Russell Low

Graeme Johnson

Andrew Johnson

Patrick R Doyle

Mike Stephen Fulton

Charles Brian Hall

Viktor Gyuris

Xin Tong

Chad Mc Intyre

Francis Bogsanyl

Charles Hall

Kirk Andrew Stewart

Mike Fulton

Patrick Doyle

Branch instructions are managed in an emulation environment that is executing a program. A plurality of slots in a Polymorphic Inline Cache is populated. A plurality of entries is populated in a branch target buffer residing within an emulated environment in which the program is executing. When an indirect branch instruction associated with the program is encountered, a target address associated with the instruction is identified from the indirect branch instruction. At least one address in each of the slots of the Polymorphic Inline Cache is compared to the target address associated with the indirect branch instruction. If none of the addresses in the slots of the Polymorphic Inline Cache matches the target address associated with the indirect branch instruction, the branch target buffer is searched to identify one of the entries in the branch target buffer that is associated with the target address of the indirect branch instruction.

Branch target buffer for emulation environments

Hybrid polymorphic inline cache and branch target buffer prediction units for indirect branch prediction for emulation environments

Embodiments of the present invention provide a method, computer program product, and system for debugging optimized code. The system includes a FAT binary, wherein the FAT binary comprises a non-optimized native code and an internal representation of a program's source code. An optimus program is configured to transform the internal representation of the program's source code into a fully optimized native code. The system also includes an enhanced loader, wherein the enhanced loader is configured to communicate with a debugger to determine a type of code to load.

Debugging optimized code using FAT binary

Debugging optimized code using fat binary

A method for optimizing binary code in a language having access to binary coded decimal variable. The method includes: generating a first compiler expression of the binary code; analyzing a use-definition and/or a definition-use for the first compiler expression; generating a second compiler expression by identifying logical binary coded decimal (BCD) variables in the first compiler expression; assigning temporary variables to the logical BCD variables, wherein the second compiler expression includes packed decimal operations and the assigned temporary variables; and converting a packed decimal operation in the second compiler expression and an assigned temporary variable to a decimal floating point (DFP) if sign information and precision information are not lost during conversion from BCD to DFP, wherein identifying logical BCD variables includes: in the use-definition and/or definition-use of operands, regarding an operand of definition and an operand of use as the same logical BCD variables.

Method for optimizing binary code in language having access to binary coded decimal variable, and computer and computer program

Hybrid polymoprhic inline cache and branch target buffer prediction units for indirect branch prediction for emulation environments

Branch instructions are managed in an emulation environment that is executing a program. A plurality of entries is populated in a branch target buffer that resides within an emulated environment in which the program is executing. Each of the entries comprises an instruction address and a target address of a branch instruction of the program. When an indirect branch instruction of the program is encountered a processor analyzes one of the entries in the branch target buffer to determine if the instruction address of the one entry is associated with a target address of the indirect branch instruction. If the instruction address of the one entry is associated with the target address of the indirect branch instruction a branch to the target address of the one entry is performed.

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.

Page mapped spatially aware emulation of computer instruction set

A code section of a computer program to be executed by a computing device includes memory barrier instructions. Where the code section satisfies a threshold, the code section is modified, by enclosing the code section within a transaction that employs hardware transactional memory of the computing device, and removing the memory barrier instructions from the code section. Execution of the code section as has been enclosed within the transaction can be monitored to yield monitoring results. Where the monitoring results satisfy an abort threshold corresponding to excessive aborting of the execution of the code section as has been enclosed within the transaction, the code section is split into code sub-sections, and each code sub-section enclosed within a separate transaction that employs the hardware transactional memory. Splitting the code section sections and enclosing each code sub-section within a separate transaction can decrease occurrence of the code section aborting during execution.

Code section optimization by removing memory barrier instruction and enclosing within a transaction that employs hardware transaction memory

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.

Just in time compiler in spatially aware emulation of a guest computer instruction set

A method, program, and apparatus for optimizing compiled code using a dynamic compiler. The method includes the steps of: generating intermediate code from a trace, which is an instruction sequence described in machine language; computing an offset between an address value, which is a base point of an indirect branch instruction, and a start address of a memory page, which includes a virtual address referred to by the information processing apparatus immediately after processing a first instruction; determining whether an indirect branch instruction that is subsequent to the first instruction causes processing to jump to another memory page, by using a value obtained from adding the offset to a displacement made by the indirect branch instruction; and optimizing the intermediate code by using the result of the determining step.

Compiling method, program, and information processing apparatus

Nested virtual machines cooperate with one another to improve system performance. In particular, an outer virtual machine performs tasks on behalf of an inner virtual machine to improve system performance. One such task includes translation of instructions for the inner virtual machine.

Performance improvements for nested virtual machines

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.

Self initialized host cell spatially aware emulation of a computer instruction set

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Toronto, Canada

Ali Ijaz Sheikh