From: Florian La Roche <florian.laroche@googlemail.com>
To: linux-kernel@vger.kernel.org
Cc: Crt Mori <cmo@melexis.com>, Joe Perches <joe@perches.com>,
Davidlohr Bueso <dave@stgolabs.net>,
Will Deacon <will.deacon@arm.com>,
Peter Zijlstra <peterz@infradead.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Florian La Roche <Florian.LaRoche@googlemail.com>
Subject: int_sqrt() adjustments
Date: Thu, 24 Jan 2019 19:21:04 +0100 [thread overview]
Message-ID: <20190124182104.18022-1-Florian.LaRoche@googlemail.com> (raw)
__fls() is returning an unsigned long, but fls() and fls64() are
both returning a (signed) int.
As we need a signed int as right operand of "<<" (as Linus pointed out),
change __fls() to fls() for 32bit and also adjust masking the lowest bit
to be a signed int.
Now the 32bit and the 64bit version are again similar.
best regards,
Florian La Roche
Signed-off-by: Florian La Roche <Florian.LaRoche@googlemail.com>
---
lib/int_sqrt.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/lib/int_sqrt.c b/lib/int_sqrt.c
index 30e0f9770f88..66eb93105812 100644
--- a/lib/int_sqrt.c
+++ b/lib/int_sqrt.c
@@ -23,7 +23,7 @@ unsigned long int_sqrt(unsigned long x)
if (x <= 1)
return x;
- m = 1UL << (__fls(x) & ~1UL);
+ m = 1UL << ((fls(x) - 1) & ~1L);
while (m != 0) {
b = y + m;
y >>= 1;
@@ -52,7 +52,7 @@ u32 int_sqrt64(u64 x)
if (x <= ULONG_MAX)
return int_sqrt((unsigned long) x);
- m = 1ULL << ((fls64(x) - 1) & ~1ULL);
+ m = 1ULL << ((fls64(x) - 1) & ~1LL);
while (m != 0) {
b = y + m;
y >>= 1;
--
2.17.1
next reply other threads:[~2019-01-24 18:21 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-24 18:21 Florian La Roche [this message]
2019-01-24 18:58 int_sqrt() adjustments Florian La Roche
2019-01-24 20:02 ` Linus Torvalds
2019-01-26 16:18 ` Florian La Roche
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