Abstract: A computer having an instruction pipeline and profile circuitry. The profile circuitry detects and records, without compiler assistance for execution profiling, profile information describing a sequence of events occurring in the instruction pipeline. The sequence includes every event occurring during a profiled execution interval that matches time-independent selection criteria of events to be profiled. The recording continues until a predetermined stop condition is reached. The profile circuitry detects the occurrence of a predetermined condition, after a non-profiled interval of execution, and then commences the profiled execution interval.

Abstract: A computer. An instruction pipeline and memory access unit execute instructions in a logical address space of a memory of the computer. An address translation circuit translates address references generated by the program from the program's logical address space to the computer's physical address space. Profile circuitry is cooperatively interconnected with the instruction pipeline and configured to detect, without compiler assistance for execution profiling, occurrence of profilable events occurring in the instruction pipeline, and is cooperatively interconnected with the memory access unit to record profile information describing physical memory addresses referenced during an execution interval of the program.

Abstract: A method and computer for performance of the method. While executing a program on a computer, the computer uses registers of a general register file for storage of instruction results. Profile information describing the profileable events is recorded into the general register file as the profileable events occur, without first capturing the information into a main memory of the computer.

Abstract: A method and computer for executing the method. A source program is translated into an object program, in a manner in which the translated object program has a different execution behavior than the source program. The translated object program is executed under a monitor capable of detecting any deviation from fully-correct interpretation before any side-effect of the different execution behavior is irreversibly committed. When the monitor detects the deviation, or when an interrupt occurs during execution of the object program, a state of the program is established corresponding to a state that would have occurred during an execution of the source program, and from which execution can continue. Execution of the source program continues primarily in a hardware emulator designed to execute instructions of an instruction set non-native to the computer.

Abstract: A method and a multiprocessor computer for execution of the method. A first CPU has a general register file, an instruciton pipeline, and profile circuitry. The profile circuitry is operatively interconnected and under common hardware control with the instruction pipeline. The profile circuitry and instruction pipeline are cooperatively interconnected to detect the occurrence of profileable events occurring in the instruction pipeline. The profile circuitry is operable without software intervention to effect recording of profile information describing the profileable events into the general register file, without first capturing the information into a main memory of the computer. The recording is essentially concurrent with the occurrence of the profileable events.

Abstract: A system for avoiding exceptional conditions during execution of a program comprises an execution enviornment for executing the program and a fix-up code generation subsystem. The program comprises an instruction stream comprising a series of instructions, and the execution environment includes an exceptional condition detector for detecting at least one predetermined type of exceptional condition in connection with execution of each instruction in the instruction stream. The fix-up code generation subsystem is responsive to detection by the execution environment of an exceptional condition of the predetermined type in connection with execution of an instruction in the instruction stream for generating fix-up code which, when processed, would avoid the exceptional condition of that predetermined type, and substitutes the fix-up code in the instruction stream for the instruction in the instruction stream for which the at least one exceptional condition was detected.

Abstract: A system for avoiding exceptional conditions during execution of a program comprises an execution environment for executing the program and a fix-up code generation subsystem. The program comprises an instruction stream comprising a series of instructions, and the execution environment includes an exceptional condition detector for detecting at least one predetermined type of exceptional condition in connection with execution of each instruction in the instruction stream. The fix-up code generation subsystem is responsive to detection by the execution environment of an exceptional condition of the predetermined type in connection with execution of an instruction in the instruction stream for generating fix-up code which, when processed, would avoid the exceptional condition of that predetermined type, and substitutes the fix-up code in the instruction stream for the instruction in the instruction stream for which the at least one exceptional condition was detected.

Abstract: A digital computer system comprises a precise exception handling processor and a control subsystem. The precise exception handling processor performs processing operations under control of instructions. The precise exception handling processor is constructed in accordance with a precise exception handling model, in which, if an exception condition is detected in connection with an instruction, the exception condition is processed in connection with the instruction. The precise exception handling processor further includes a pending exception indicator having a pending exception indication state and a no pending exception indication state. The control subsystem provides a series of instructions to the precise exception handling processor to facilitate emulation of at least one emulated program instruction.

Abstract: A processor processes a segmented to linear virtual address conversion instruction to convert segmented virtual addresses in a segmented virtual address space to a linear virtual address in a linear virtual address space. The segmented virtual address space comprises a plurality of segments each identified by a segment identifier, each segment comprising at least one page identified by a page identifier. The linear virtual address space includes a plurality of pages each identified by a page identifier. In processing the segmented to linear virtual address conversion instruction, the processor uses a plurality of segmented to linear virtual address conversion descriptors, each associated with a page in the segmented virtual address space, each segmented to linear virtual address conversion descriptor identifying the page identifier of one of the pages in the linear virtual address space.