HelpPC 2.10 Quick Reference Utility Copyright 1991 David Jurgens

                               LOCK - Lock Bus

       Usage:  LOCK
               LOCK: (386+ prefix)
       Modifies flags: None

       This instruction is a prefix that causes the CPU assert bus lock
       signal during the execution of the next instruction.  Used to
       avoid two processors from updating the same data location.  The
       286 always asserts lock during an XCHG with memory operands.  This
       should only be used to lock the bus prior to XCHG, MOV, IN and
       OUT instructions.

                                Clocks                 Size
       Operands         808x  286   386   486          Bytes

       none              2     0     0     1             1

       - see Instruction Timing

Esc or Alt-X to exit lock Home/PgUp/PgDn/End ←↑↓→
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