Introduce SETBITFIELD(msb, lsb, value) macro to ease dealing with continuous bitfields, just as BIT(x) does for single bits.
SETBITFIELD_ULL(msb, lsb, value) macro is also added. Signed-off-by: Sebastian Frias <s...@laposte.net> --- Code protected with "#ifdef __KERNEL__" just as the BIT(x) macros. I would have preferred another name, like BITS(x) but it is already used. Suggestions for other names welcome. --- include/linux/bitops.h | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/include/linux/bitops.h b/include/linux/bitops.h index a83c822..4659237 100644 --- a/include/linux/bitops.h +++ b/include/linux/bitops.h @@ -24,6 +24,20 @@ #define GENMASK_ULL(h, l) \ (((~0ULL) << (l)) & (~0ULL >> (BITS_PER_LONG_LONG - 1 - (h)))) +#ifdef __KERNEL__ +/* + * Equivalent of BIT(x) but for contiguous bitfields + * SETBITFIELD(1, 0,0xff) = 0x00000003 + * SETBITFIELD(3, 0,0xff) = 0x0000000f + * SETBITFIELD(15,8,0xff) = 0x0000ff00 + * SETBITFIELD(6, 6, 1) = 0x00000040 == BIT(6) + */ +#define SETBITFIELD(msb, lsb, val) \ + (((val) << (lsb)) & (GENMASK((msb), (lsb)))) +#define SETBITFIELD_ULL(msb, lsb, val) \ + (((val) << (lsb)) & (GENMASK_ULL((msb), (lsb)))) +#endif + extern unsigned int __sw_hweight8(unsigned int w); extern unsigned int __sw_hweight16(unsigned int w); extern unsigned int __sw_hweight32(unsigned int w); -- 1.8.3.1