Method and apparatus for re-creating the trace of an emulated instruction set when executed on hardware native to a different instruction set field

An execution trace buffer (ETB) for use in debugging a system comprising:

• a plurality of registers capable of holding information regarding executed instructions as the instructions are processed, wherein instructions are executed by an execution engine and are retired while the execution engine executes other instructions, and wherein the information stored in the registers varies depending upon a pre-selected mode of operation, and comprises macroinstruction address information when operating in a macroinstruction mode and micro-ip address information when operating in a microinstruction mode;
• a pointer identifying a register into which an instruction is written;
• and
• a bus connected to the ETB capable of reading the information on the ETB,
• wherein the ETB is adapted to operate in a mixed-architecture processor that processes both microinstructions and macroinstructions, and wherein the ETB holds information related to microinstructions and macro instructions.

A computer system capable of assisting a user to debug the system comprising:

• a retire stage of an execution engine that holds information regarding executed instructions, wherein the execution engine processes both macroinstructions and microinstructions;
• and
• an execution trace buffer (ETB) connected to the execution engine, which ETB receives information regarding executed instructions, wherein the information varies depending upon a pre-selected mode of operation, wherein the ETB operates in a macroinstruction mode and in a microinstruction mode, wherein the information comprises macroinstruction address information when operating in the macroinstruction mode and micro-ip address information when operating in the microinstruction mode, and
• wherein the ETB receives the information while the execution engine processes another instruction.