Re: [ANNOUNCE] CMOV emulation for 2.4.19-rc1
Denis Vlasenko (vda@port.imtp.ilyichevsk.odessa.ua)
Mon, 1 Jul 2002 16:16:44 -0200
On 1 July 2002 11:03, willy tarreau wrote:
> Hello Denis,
>
> > This code is performance critical.
> > With this in mind,
>
> Yes and no. In fact, I first wanted to code some
> parts in assembler because GCC is sub-optimal
> on bit-fields calculations. But then, I realized that
> I could save, say 10 cycles, while the trap costs
> about 400 cycles.
Can you code up a "dummy" emulator (which just ignores
any invalid opcode by doing eip+=3) and compare trap times
of your emulator and dummy one for, say, CMOVC AL,AL?
(with carry flag cleared)
--
vda
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