atomic accesses

[Segher Boessenkool]

>> The Linux kernel, and probably some user-space applications and 
>> libraries
>> as well, depend on GCC guaranteeing (a variant of) the following:
>> 	"any access to a naturally aligned scalar object in memory
>> 	that is not a bit-field will be performed by a single machine
>> 	instruction whenever possible"
>> and it seems the current compiler actually does work like this.
>
> Seems a pity to have the bit-field exception here, why is it there?

Bit-fields will generally require a read-modify-write instruction,
and I don't think we actually guarantee to generate one right now.


Segher