A method, system, apparatus, and computer program product is presented for
processing instructions. A processor is able to receive multiple types of
interruptions while executing instructions, such as aborts, faults,
interrupts, and traps. A set of processor fields are used to indicate
whether or not one or more trap modes are active, such as a single-step
trap mode or a taken-branch trap mode. The activity of a trap mode is
conditioned, i.e., restricted, modified, or qualified, with a trap mode
conditioning field that indicates whether or not the trap mode should
remain active during interruption processing. The use of a trap mode
conditioning field allows an interruption handler to run at full speed
without being interrupted by the trap mode, yet the trap mode is
preserved so that other processing, such as instruction tracing, may
continue after interruption processing.