Abstract: One embodiment of the present invention provides a system that uses value speculation to break constraining dependencies in loops. The system operates by first identifying a loop within a computer program, and then identifying a dependency on a long-latency operation within the loop that is likely to constrain execution of the loop. Next, the system breaks the dependency by modifying the loop to predict a value that will break the dependency, and then using the predicted value to speculatively execute subsequent loop instructions.

Abstract: An automatic and retargetable computer design system is using a combination of simulation and performance prediction to investigate a plurality of target computer systems. A high-level specification and a predetermined application are used by the computer design system to provide inputs into a computer evaluator. The computer evaluator has reference computer system dependent and independent systems for producing a reference representation and dynamic behavior information, respectively, of the application. The reference representation and information are mated to produce further information to drive a simulator. The simulator provides performance information of a reference computer system. The performance information is provided to another computer evaluator, which has a target computer system dependent system for producing a target representation of the application for the plurality of target computer systems.

Abstract: One embodiment of the present invention provides a system that dynamically allocates physical registers in a windowed processor architecture. The system includes a physical register file and a register map that maps architectural registers defined within an executing program to physical registers within the physical register file. The system also includes a window allocation mechanism that allocates a new name space for a register window without allocating physical registers for the register window, thereby allowing the physical registers to be dynamically allocated as needed instead of being allocated at window initialization time.

Abstract: One embodiment of the present invention provides a system that redirects control flow of original code to transformed code. The system includes a computer processor with an instruction fetch unit that determines a next instruction to be executed by the processor. The system also includes a control redirection buffer, which indicates whether to conditionally redirect execution from a first instruction address to a second instruction address so that the transformed code at the second instruction address can be executed in place of the original code at the first instruction address.

Abstract: A system is provided which simplifies and speeds up the process of designing a computer system by evaluating the components of the memory hierarchy for any member of a broad family of processors in an application-specific manner. The system uses traces produced by a reference processor in the design space for a particular cache design and characterizes the differences in behavior between the reference processor and an arbitrarily chosen processor. The differences are characterized as a series of dilation parameters which relate to how much the traces would expand because of the substitution of a target processor. In addition, the system characterizes the reference trace using a set of trace parameters that are part of a cache behavior model. The dilation and trace parameters are used to determine the factors for estimating the performance statistics of target processors with specific memory hierarchies.