CLI             Clear Interrupt-Enable Flag          Flags: O D I T S Z A P C
                                                            - - 0 - - - - - -
CLI                                                  IO

        Logic   IF ← 0

    External interrupts are ignored at the end of CLI until the
    interrupt flag (IF) is set to one. Non-maskable interrupts are
    recognized no matter what the state of IF. CLI and STI have no
    effect on software interrupts - those generated by an INT
    instruction or by the occurrence of a divide fault and similar
    conditions.

    Protected mode
    If the current privilege level (CPL) is at least as privileged as
    the input/output privilege level (IOPL -- bits 12 and 13 of the
    FLAGS register), CLI resets IF to zero. A general protection
    exception generated is if the program does not have the correct
    I/O privilege.


    Opcode      Format
    FA          CLI


    Length and timing
    Operands    Bytes   8088    186     286     386     486     Pentium
    -            1       2       2       3       3       5       7   NP