BT              Bit Test                             Flags: O D I T S Z A P C
                                                            - - - - - - - - *
BT destination,source                                CPU: 386+

        Logic   CF ← bit from destination at position source

    The source specifies a bit index in the destination operand.
    BT copies that bit to the carry flag.


    Opcode      Format
    0F A3       BT  r/m16,r16
    0F A3       BT  r/m32,r32
    0F BA /4 ib BT  r/m16,imm8
    0F BA /4 ib BT  r/m32,imm8


    Length and timing
    Operands    Bytes   8088    186     286     386     486     Pentium
    reg, reg      3                              3       3       4   NP
    mem, reg    3+d(0,1,2,4)                    12       8       9   NP
    reg, imm8     3+i(1)                         3       3       4   NP
    mem, imm8   3+d(0,1,2,4)+i(1)                6       3       4   NP