#define reg_def(pos, size) pos, (((0x1 << size) - 1) << pos)

#define reg_set(reg, field) _reg_set(reg, field)
#define _reg_set(reg, pos, mask) do { reg.word |= mask; } while (false)

#define reg_reset(reg, field) _reg_reset(reg, field)
#define _reg_reset(reg, pos, mask) do { reg.word &= ~mask; } while (false)

#define reg_write(reg, field, value) _reg_write(reg, field, value)
#define _reg_write(reg, pos, mask, value) \
do {                                      \
	reg.word |= value << pos;             \
} while (false)                           \