uses of break , cop , nop
Joe Boctor
Hi!
What are the commons uses of break, cop, nop instructions on many of the
current processors?
thnx for any input,
Joe
Alexei A. Frounze
news:2001021503...@odin.asgard...
>
> Hi!
>
> What are the commons uses of break, cop, nop instructions on many of the
> current processors?
what are break and cop?
seems x86 doesn't have a nop.
db 90h is xhchg ax, ax or something which doesn't do anything. :)
I think nop is not a big deal. more importand might be halt - e.g. just wait
for an IRQ which probably can save some energy if HLT somehow helps CPU to
change power consumption mode.
Good Luck
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Alexei A. Frounze
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Barry Kelly
>
> What are the commons uses of break, cop, nop instructions on many of the
> current processors?
No idea about break and cop, but nop is quite important for compiler
writers. It helps to align code, and to allow a peephole optimizer to run on
code. The peephole optimizer can replace long instruction sequences with
shorter ones, and fill the gaps with nops. This means the code is still
executable, and a later stage which runs through the code to compact and
remove the nops can be developed separately.