[PATCH] drivers/sbus/char: Micro-optimization in display7seg.c

From: Rasmus Villemoes
Date: Thu Jun 19 2014 - 08:34:28 EST


Flipping a bit doesn't need four lines of code; and gcc seems to
actually generate two branches.

Signed-off-by: Rasmus Villemoes <linux@xxxxxxxxxxxxxxxxxx>
---
drivers/sbus/char/display7seg.c | 5 +----
1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/drivers/sbus/char/display7seg.c b/drivers/sbus/char/display7seg.c
index 7c71e7b..3221dff 100644
--- a/drivers/sbus/char/display7seg.c
+++ b/drivers/sbus/char/display7seg.c
@@ -143,10 +143,7 @@ static long d7s_ioctl(struct file *file, unsigned int cmd, unsigned long arg)

case D7SIOCTM:
/* toggle device mode-- flip display orientation */
- if (regs & D7S_FLIP)
- regs &= ~D7S_FLIP;
- else
- regs |= D7S_FLIP;
+ regs ^= D7S_FLIP;
writeb(regs, p->regs);
break;
}
--
1.9.2

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/