DIAGNOSING CODE USING SINGLE STEP EXECUTION

摘要

A method and apparatus for diagnosing a processor processing a stream of instructions are disclosed. The method comprises the steps of: (i) controlling the processor to execute in a single step mode such that a single instruction from the instruction stream is executed, the processor determines if the single instruction is one of at least one predetermined type of instruction and stores a type indicator in a data storage location and a diagnostic exception is taken after the processor has processed the single instruction; (ii) performing diagnostic operations following the diagnostic exception including: accessing the type indicator stored in the data storage location; and (iiia) in response to the type indicator indicating the single instruction was not one of the predetemined type controlling the processor to continue executing instructions in the single step mode such that a next single instruction is executed on return form the exception; (iiib) in response to the type indicator indicating the single instruction was one of the at least one predetermined type controlling the processor to exit the single step mode and not execute the next instruction within the instruction stream as a single instruction followed by an exception.