IN              Input from Port                      Flags: Not altered

IN accumulator,port                                  IOpm

        Logic   accumulator ← [port]

    IN reads a byte, word, or a doubleword from a specified port and
    stores it in AL, AX, or EAX. The port number is specified as an
    immediate byte value (for ports 0 thru 255) or by the DX register
    (allowing access to all ports).

    Protected mode
    An exception occurs if the current task has insufficient privilege
    for the I/O. IN is not IOPL-sensitive in V86 mode.


    Opcode      Format
    E4 ib       IN  AL,imm8
    E5 ib       IN  AX,imm8
    E5 ib       IN  EAX,imm8
    EC          IN  AL,DX
    ED          IN  AX,DX
    ED          IN  EAX,DX


    Length and timing
    Operands    Bytes   8088    186     286     386     486     Pentium
    al, imm8     2      14      10       5      12      14       7   NP
    ax, imm8     2      14      10       5      12      14       7   NP
    eax, imm8    2       -       -       -      12      14       7   NP
    al, dx       1      12       8       5      13      14       7   NP
    ax, dx       1      12       8       5      13      14       7   NP
    eax, dx      1       -       -       -      13      14       7   NP

                             Protected mode
    acc, imm     2                           6/26/26  9/29/27  4/21/19 NP
    acc, dx      1                           7/27/27  8/28/27  4/21/19 NP

                   Cycles for: CPL <= IOPL / CPL > IOPL / V86