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SubjectRe: [PATCH] NTP shift_right cleanup (v. A3)
On 21 Sep 2005 at 15:24, Nick Piggin wrote:

> john stultz wrote:
>
> >
> >+/* Required to safely shift negative values */
> >+#define shift_right(x, s) ({ \
> >+ __typeof__(x) __x = (x); \
> >+ __typeof__(s) __s = (s); \
> >+ __x < 0 ? -(-__x >> __s) : __x >> __s; \
> >+})
> >+
> >
>
> I'd hate to be the one to make you do another version of this ;)
>
> However, how about having something more descriptive than shift_right?
> signed_shift_right / shift_right_signed, maybe?

Hi,

I'm against "signed shift right", because the reason for the macro is exaclty that
CPUs do a "signed" shift right. John does a "signum(arg) * right_shift(abs(arg),
number_of_positions)". So maybe it's the signed_unsigned_shift_right(), susr() to
be cryptic ;-)

I'm only surprised that there are many places where such a routine is needed, and
still it's missing in sime bitops.h #include.

Regards,
Ulrich

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