BT                Bit Test (386)                     Flags: O D I T S Z A P C
                                                                            *
BT destination, source

           Logic:      CF . bit from destination at position source

     The Bit Test instructions manipulate individual bits. The source
     specifies a bit position in the destination operand. BT copies that
     bit to the carry flag.

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   Operands                   Clocks   Transfers  Bytes  Example
   BT register, immediate8    3  (386)     -        3    BT AX,3
   BT memory, immediate8      6  (386)     -        3    BT MEMLOC,3
   BT register, register      3  (386)     -        3    BT AX,BX
   BT memory, register        12 (386)     -        3    BT MEMLOC,AX
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        Note:          Both memory and register operands can be either
                       16 bits or 32 bits (80386).