On Mon, Mar 16, 2015 at 11:37:44PM +0100, Quentin Casasnovas wrote:
...
> __user_insn("btl [var2], %0 \n\t",
> , /* no outputs, no need for dummy arg */
> SINGLE_ARG("r" (var1), [var2] "r" (var2)), /* two inputs */
> "cc");
So this becomes pretty unreadable IMO. And we shouldn't go nuts with
optimizing this and sacrifice readability a lot.
TBH, I'd much prefer:
if (static_cpu_has_safe(X86_FEATURE_XSAVEOPT)) {
check_insn(XSAVEOPT, ...);
return;
}
if (static_cpu_has_safe(X86_FEATURE_XSAVES)) {
check_insn(XSAVES);
return;
}
check_insn(XSAVE, ...)
which is pretty clear.
We can even go a step further and add a static_cpu_has_safe thing which
checks two features instead of one. The penalty we'd get is a single
inconditional JMP which in the face of XSAVE* is nothing.
--
Regards/Gruss,
Boris.
ECO tip #101: Trim your mails when you reply.
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