SCASD             Scan String Doubleword (386)       Flags: O D I T S Z A P C
                                                            *       * * * * *
SCASD

       Logic:              CMP EAX, DWORD PTR ES:DI
                           if DF = 0 then
                               DI . DI + 4
                           else
                               DI . DI - 4

     This instruction compares the value in EAX to the doubleword at
     location ES:DI. The flags are set accordingly. If the direction flag
     is set, DI is decremented by 4. If it is not set, EDI is incremented
     by 4.

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   Operands                   Clocks   Transfers  Bytes  Example
   SCASD                      7 (386)      -        1    SCASD
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        Note:          This instruction is usually used with a REP
                       prefix. Load CX with the number of times to repeat
                       the instruction. You can only use SCASD on the 80386.