All these operations, which are necessary for a subroutine call, are completed in four cycles with the ENTER instruction. Locating the Frame Base pointer as part of the instruction allows the compiler to use the efficient Frame Base Relative (FBR) addressing mode to access variable information. At the end of the subroutine, the 2-byte EXITD instruction removes the temporary stack frame and restores the original Stack Pointer and Frame Base values. It also performs the return-from-subroutine function.

