[En-Nut-Discussion] Writting a new UART device -- I solved the problem , very weird

[Avex]

> 
> >if(idx > limit) idx = 0;
> 
> >within interrupt routines degrades system performance.
> 
> If you simply increment the index and then mask off the two high bits with
> an 'and', you will get a 64 byte rollover. Add the index to the base address
> & voila...  works a treat, fast & easy to implement in asm in the interrupt
> driver.
Hi Don,

I didn't mask any ....bit , I rewrote uartspi & uartavr to a new file as my new 
device driver. It's no reason ,why we could mask any ... bit whenever 
developing a driver of NutOS. I cann't figure out.

Avex
 


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