Newsflash: GCC not as smart as once hoped.
This patch removes some mults since GCC can't figure out how.
Pointed out by Roman Zippel.
Signed-off-by: John Stultz <[email protected]>
diff --git a/include/linux/clocksource.h b/include/linux/clocksource.h
index 585789f..5f4a7f7 100644
--- a/include/linux/clocksource.h
+++ b/include/linux/clocksource.h
@@ -236,7 +236,6 @@ static inline int error_aproximation(u64
*
* Where mult_delta is the adjustment value made to mult
*
- * XXX - Hopefully gcc is smart enough to avoid the multiplies.
*/
static inline s64 make_ntp_adj(struct clocksource *clock,
cycles_t cycles_delta, s64* error)
@@ -244,27 +243,27 @@ static inline s64 make_ntp_adj(struct cl
s64 ret = 0;
if (*error > ((s64)clock->interval_cycles+1)/2) {
/* calculate adjustment value */
- int adjustment = 1 << error_aproximation(*error,
+ int adjustment = error_aproximation(*error,
clock->interval_cycles);
/* adjust clock */
- clock->mult += adjustment;
- clock->interval_snsecs += clock->interval_cycles * adjustment;
+ clock->mult += 1 << adjustment;
+ clock->interval_snsecs += clock->interval_cycles << adjustment;
/* adjust the base and error for the adjustment */
- ret = -(cycles_delta * adjustment);
- *error -= clock->interval_cycles * adjustment;
+ ret = -(cycles_delta << adjustment);
+ *error -= clock->interval_cycles << adjustment;
/* XXX adj error for cycle_delta offset? */
} else if ((-(*error)) > ((s64)clock->interval_cycles+1)/2) {
/* calculate adjustment value */
- int adjustment = 1 << error_aproximation(-(*error),
+ int adjustment = error_aproximation(-(*error),
clock->interval_cycles);
/* adjust clock */
- clock->mult -= adjustment;
- clock->interval_snsecs -= clock->interval_cycles * adjustment;
+ clock->mult -= 1 << adjustment;
+ clock->interval_snsecs -= clock->interval_cycles << adjustment;
/* adjust the base and error for the adjustment */
- ret = cycles_delta * adjustment;
- *error += clock->interval_cycles * adjustment;
+ ret = cycles_delta << adjustment;
+ *error += clock->interval_cycles << adjustment;
/* XXX adj error for cycle_delta offset? */
}
return ret;
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Stuff]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
[Linux Resources]