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SBB             Subtract with Borrow                 Flags: O D I T S Z A P C
                                                            * - - - * * * * *
SBB destination,source

        Logic   destination . destination - source - CF

    SBB subtracts the source operand from the destination operand,
    subtracts 1 from that result if the carry flag is set, and stores
    the result in destination.

    When an immediate byte value is subtracted from a (double)word
    operand, the immediate value is first sign-extended to the size of
    the destination operand.


    Opcode      Format
    18 /r       SBB  r/m8,r8
    19 /r       SBB  r/m16,r16
    19 /r       SBB  r/m32,r32
    1A /r       SBB  r8,r/m8
    1B /r       SBB  r16,r/m16
    1B /r       SBB  r32,r/m32
    1C ib       SBB  AL,imm8
    1D iw       SBB  AX,imm16
    1D id       SBB  EAX,imm32
    80 /3 ib    SBB  r/m8,imm8
    81 /3 iw    SBB  r/m16,imm16
    81 /3 id    SBB  r/m32,imm32
    83 /3 ib    SBB  r/m16,imm8
    83 /3 ib    SBB  r/m32,imm8


    Length and timing
    Operands    Bytes   8088    186     286     386     486     Pentium
    reg, reg     2       3       3       2       2       1       1   PU
    mem, reg  2+d(0,2)  24+EA   10       7       7       3       3   PU
    reg, mem  2+d(0,2)  13+EA   10       7       6       2       2   PU
    reg, imm  2+i(1,2)   4       4       3       2       1       1   PU
    mem, imm  2+d(0,2)  23+EA   16       7       7       3       3   PU*
               +i(1,2)
    acc, imm  1+i(1,2)   4       4       3       2       1       1   PU

       * = not pairable if there is a displacement and immediate