Online HelpPC 2.10 Quick Reference Utility Copyright 1991 David Jurgens
CMPS - Compare String (Byte, Word or Doubleword)
Usage: CMPS dest,src
CMPSB
CMPSW
CMPSD (386+ only)
Modifies flags: AF CF OF PF SF ZF
Subtracts destination value from source without saving results.
Updates flags based on the subtraction and the index registers
(E)SI and (E)DI are incremented or decremented depending on the
state of the Direction Flag. CMPSB inc/decrements the index
registers by 1, CMPSW inc/decrements by 2, while CMPSD increments
or decrements by 4. The REP prefixes can be used to process
entire data items.
Clocks Size
Operands 808x 286 386 486 Bytes
dest,src 22 8 10 8 1 (W88=30)
- see Instruction Timing
[helppc.bosbyte.nl] cmps