.286c            Enable Real Mode 80286 Instructions           MASM Directive

  .286c

    Enables assembly of 80286 real mode instructions, as well as 8086 and
    80186 instructions (80186 instructions are identical to 80286 real
    mode instructions).

       Notes:     This directive should be used for programs that execute
                  only on an 80286 (or 80386) in real mode.

                  Place all Instruction set directives at the beginning of
                  the source file to insure that all instructions in the
                  file are assembled using the same microprocessor
                  instruction set.

                  See .286p for a directive which will generate code for
                  the protected mode of the 80286.