Instruction pointer

    The Extended Instruction Pointer (EIP) is a 32-bit register. EIP
    contains the offset address of the next sequential instruction to
    be executed. This offset is relative to the start (or base
    address) of the current code segment. The EIP is not directly
    visible to programmers but is controlled explicitly by control-
    transfer instructions, interrupts, and exceptions.

    The low-order 16 bits of EIP are named IP and can be used by the
    processor as a unit when executing 8086/80186/80286 code.