US Patent 7444501 Methods and apparatus for recognizing a subroutine call

An apparatus for recognizing a subroutine call is disclosed. The apparatus includes a circuit comprising a first input for receiving contents of a register, a second input for receiving a non-sequential change in program flow, and a third input for receiving the next sequential address after the non-sequential change in program flow. The circuit is configured to compare the next sequential address and the contents of the register to determine whether the non-sequential change in program flow is a subroutine call.