Messages in this thread Patch in this message | | | Date | Sat, 10 Sep 2005 03:39:48 +0200 (CEST) | From | Roman Zippel <> | Subject | Re: [RFC][PATCH] NTP shiftR cleanup |
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Hi,
On Fri, 9 Sep 2005, john stultz wrote:
> +/* Required to safely shift negative values */ > +#define shiftR(x, s) ({ __typeof__(x) __x = x;\ > + __typeof__(s) __s = s; \ > + (__x < 0) ? (-((-__x) >> (__s))) : ((__x) >> (__s));}) > +
Some parenthesis are missing and some are redundant. Formatting it so it looks more like normal function makes it more readable:
#define shiftR(x, s) ({ \ __typeof__(x) __x = (x); \ __typeof__(s) __s = (s); \ __x < 0 ? -(-__x >> __s) : __x >> __s; \ })
> @@ -792,13 +769,8 @@ static void update_wall_time_one_tick(vo > * advance the tick more. > */ > time_phase += time_adj; > - if (time_phase <= -FINENSEC) { > - long ltemp = -time_phase >> (SHIFT_SCALE - 10); > - time_phase += ltemp << (SHIFT_SCALE - 10); > - delta_nsec -= ltemp; > - } > - else if (time_phase >= FINENSEC) { > - long ltemp = time_phase >> (SHIFT_SCALE - 10); > + if (abs(time_phase) >= FINENSEC) { > + long ltemp = shiftR(time_phase, (SHIFT_SCALE - 10)); > time_phase -= ltemp << (SHIFT_SCALE - 10); > delta_nsec += ltemp; > }
It would be interesting to check, whether gcc produces the same code here.
bye, Roman - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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