ESC              Escape                              Flags: not altered

ESC coprocessor's-opcode,source

    ESC is used to pass control from the microprocessor to a coprocessor,
    such as an 8087 or 80287. In response to ESC, the microprocessor
    accesses a memory operand--the instruction for the coprocessor--and
    places it on the bus. The coprocessor watches for ESC commands and
    executes the instruction placed on the bus, using the effective
    address of source.

  --------------------------------------------------------------------------
   Operands                  Clocks   Transfers  Bytes   Example
                           byte(word)
   immediate, memory       8(12) + EA     1       2-4    ESC 6,ADR[SI]
   immediate, register         2          -        2     ESC COPROC-CODE,AH
  --------------------------------------------------------------------------

       Notes:         In order to synchronize with the math coprocessor,
                      the programmer must explicitly code the WAIT
                      instruction preceding all ESC instructions.  The
                      80286 and 80386 have automatic instruction
                      synchronization, hence WAITs are not needed.