Online 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
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