RSM             Resume from System Management Mode  Flags: O D I T S Z A P C
                                                           * * * * * * * * *
RSM                                                 CPU: Pentium+  r

        Logic ReturnFromSSM
                ProcessorState ← Restore(SSMDump)

    Returns program control from system management mode (SMM) to the
    application program or operating system procedure that was
    interrupted when the processor received an SSM interrupt. The
    processor's state is restored from the dump created upon entering
    SMM. If the processor detects invalid state information during state
    restoration, it enters the shutdown state. The following invalid
    information can cause a shutdown:

    - Any reserved bit of CR4 is set to 1.
    - Any illegal combination of bits in CR0, such as
      (PG=1 and PE=0) or (NW=1 and CD=0).
    - (Intel Pentium and Intel486 only.) The value stored in the state
      dump base field is not a 32-KByte aligned address.

    The contents of the model-specific registers are not affected by a
    return from SMM.

    See Chapter 9 in the Pentium Pro Family Developer's Manual, Volume 3
    for more information about SMM and the behavior of the RSM
    instruction.


    Protected Mode Exceptions
    #UD If an attempt is made to execute this instruction when the
    processor is not in SMM.

    Real Address Mode Exceptions
    #UD If an attempt is made to execute this instruction when the
    processor is not in SMM.

    Virtual 8086 Mode Exceptions
    #UD If an attempt is made to execute this instruction when the
    processor is not in SMM.


    Opcode      Format
    0F AA       RSM


    Length and timing
    Operands    Bytes   8088    186     286     386     486     Pentium
    -           2       -       -       -       -       -       -