Apparatus and method for tracing microprocessor instructions

摘要

A microprocessor implements an instruction tracing mechanism that saves the state of the microprocessor without special hardware. Prior to the execution of a traced instruction, a trace microcode routine is implemented that saves the state of the microprocessor to external memory. The state information saved by the trace microcode routine varies depending upon the amount of data needed by the end user. After the state of the processor has been saved, the trace instruction is executed. State information that changed during the execution of the trace instruction is saved to memory prior to a subsequent instruction. The trace instruction mechanism advantageously requires minimal special hardware and expedites the saving of the processor state information.