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Message-Id: <1417190476-18066-3-git-send-email-linux@rasmusvillemoes.dk> Date: Fri, 28 Nov 2014 17:01:05 +0100 From: Rasmus Villemoes <linux@...musvillemoes.dk> To: Andrew Morton <akpm@...ux-foundation.org>, Jan Kara <jack@...e.cz> Cc: linux-kernel@...r.kernel.org Subject: [PATCH 2/7] lib: bitmap: Eliminate branch in __bitmap_shift_right We can shift the bits from lower and upper into place before assembling dst[k]; moving the shift of upper into the branch where we already know that rem is non-zero allows us to remove a conditional. Signed-off-by: Rasmus Villemoes <linux@...musvillemoes.dk> --- lib/bitmap.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/lib/bitmap.c b/lib/bitmap.c index 2332115..9250c3f 100644 --- a/lib/bitmap.c +++ b/lib/bitmap.c @@ -127,13 +127,13 @@ void __bitmap_shift_right(unsigned long *dst, const unsigned long *src, upper = src[off + k + 1]; if (off + k + 1 == lim - 1 && left) upper &= mask; + upper <<= (BITS_PER_LONG - rem); } lower = src[off + k]; if (left && off + k == lim - 1) lower &= mask; - dst[k] = lower >> rem; - if (rem) - dst[k] |= upper << (BITS_PER_LONG - rem); + lower >>= rem; + dst[k] = lower | upper; if (left && k == lim - 1) dst[k] &= mask; } -- 2.0.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.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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