BKEY_EXPONENT_BITS  239 drivers/md/bcache/bset.c #define BKEY_MANTISSA_BITS	(32 - BKEY_MID_BITS - BKEY_EXPONENT_BITS)
BKEY_EXPONENT_BITS  243 drivers/md/bcache/bset.c 	unsigned int	exponent:BKEY_EXPONENT_BITS;