> The proposed code is faster in all cases.  Additionally, it's logically
> simpler, straightforward, and doesn't use hard-coded knowledge of where
> the interrupt bits live in the csr.
>
> While I was at it, I removed the unnecessary do from inside the CALLINTR
> macro - I useta know why folks did that, but I've forgotten and its not
> necessary here in any case.

do {} while is a mandory.  ifound variable is for the case in which CSR
bit is changed inside any interrupt handlers.

Tohru Nishimura