CBW              Convert Byte to Word                Flags: not altered
 
CBW
 
          Logic:    if (AL < 80h) then
                        AH  0
                    else
                        AH  FFh
 
    CBW extends the sign bit of the AL register into the AH register. This
    instruction extends a signed byte value into the equivalent signed
    word value.
 
  --------------------------------------------------------------------------
   Operands                  Clocks   Transfers  Bytes   Example
   no operands                 2          -        1     CBW
  --------------------------------------------------------------------------
 
       Note:          This instruction will set AH to 0FFh if the sign bit
                      (bit 7) of AL is set; if bit 7 of AL is not set, AH
                      will be set to 0. The instruction is useful for
                      generating a word from a byte prior to performing
                      byte division.

Seealso:


 CWD 
 DIV 
 IDIV