atomic_t (24 bits???)

[Richard B. Johnson]

In ../linux/include/asm/atomic.h, for versions 2.4.18 and
above as far as I've checked, there are repeated warnings
"Note that the guaranteed useful range of an atomic_t is
only 24 bits."

I fail to see any reason why as atomic_t is typdefed to a
volatile int which, on ix86 seems to be 32 bits.

Does anybody know if this is just some old comments from a
previous atomic_t type of, perhaps, char[3]?  

Cheers,
Dick Johnson
Penguin : Linux version 2.4.18 on an i686 machine (797.90 BogoMips).
Why is the government concerned about the lunatic fringe? Think about it.