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Commit d67be61e authored by Trent Piepho's avatar Trent Piepho Committed by Mauro Carvalho Chehab
Browse files

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: default avatarTrent Piepho <xyzzy@speakeasy.org>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@infradead.org>
parent ba2cf982

drivers/media/common/ir-functions.c

+11 −12
Original line number Diff line number Diff line
@@ -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;



	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++;

	do {

	    if (mask&1) {

		if (data&1)

			value |= vbit;

		vbit<<=1;

	    }

	    data>>=1;

	} while (mask>>=1);



	return value;

}