diff options
| author | Trent Piepho <xyzzy@speakeasy.org> | 2007-07-11 20:28:44 -0300 |
|---|---|---|
| committer | Mauro Carvalho Chehab <mchehab@infradead.org> | 2007-07-18 14:24:42 -0300 |
| commit | d67be61ebe5efaf9c4c11bf168781d678854c966 (patch) | |
| tree | 42da70f931f36b01e3cc8e516eb260212b8a650e | |
| parent | ba2cf98249795f03792d1409a3b6aaa589ea0745 (diff) | |
V4L/DVB (5832): ir-common: optimize bit extract function
New code is simpler, shorter, compiles to about half the size, and is 2
to 4 times faster depending on how many bits in the mask are set.
Signed-off-by: Trent Piepho <xyzzy@speakeasy.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>
| -rw-r--r-- | drivers/media/common/ir-functions.c | 23 |
1 files changed, 11 insertions, 12 deletions
diff --git a/drivers/media/common/ir-functions.c b/drivers/media/common/ir-functions.c index fcb194135627..fe447a06e24e 100644 --- a/drivers/media/common/ir-functions.c +++ b/drivers/media/common/ir-functions.c @@ -107,21 +107,20 @@ void ir_input_keydown(struct input_dev *dev, struct ir_input_state *ir, } /* -------------------------------------------------------------------------- */ - +/* extract mask bits out of data and pack them into the result */ u32 ir_extract_bits(u32 data, u32 mask) { - int mbit, vbit; - u32 value; + u32 vbit = 1, value = 0; + + do { + if (mask&1) { + if (data&1) + value |= vbit; + vbit<<=1; + } + data>>=1; + } while (mask>>=1); - value = 0; - vbit = 0; - for (mbit = 0; mbit < 32; mbit++) { - if (!(mask & ((u32)1 << mbit))) - continue; - if (data & ((u32)1 << mbit)) - value |= (1 << vbit); - vbit++; - } return value; } |