From: Andy Shevchenko <andy.shevchenko@gmail.com>
To: Jiri Kosina <jkosina@suse.cz>, linux-input@vger.kernel.org
Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
Subject: [PATCH] HID: core: don't use negative operands when shift
Date: Wed, 7 Jan 2015 01:17:15 +0200 [thread overview]
Message-ID: <1420586235-27660-1-git-send-email-andy.shevchenko@gmail.com> (raw)
The recent C standard in 6.5.7 paragraph 4 defines that operands for
bitwise shift operators should be non-negative, otherwise it's an
undefined behaviour.
Signed-off-by: Andy Shevchenko <andy.shevchenko@gmail.com>
---
drivers/hid/hid-core.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c
index f2a4879..99307f0 100644
--- a/drivers/hid/hid-core.c
+++ b/drivers/hid/hid-core.c
@@ -1027,7 +1027,7 @@ static s32 snto32(__u32 value, unsigned n)
case 16: return ((__s16)value);
case 32: return ((__s32)value);
}
- return value & (1 << (n - 1)) ? value | (-1 << n) : value;
+ return value & (1 << (n - 1)) ? value | (~0U << n) : value;
}
s32 hid_snto32(__u32 value, unsigned n)
--
1.8.3.101.g727a46b
reply other threads:[~2015-01-06 23:25 UTC|newest]
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