Re: [avr-chat] portable no-op with AVR GCC, AVR LIbc?

[Anthony Andriano]

I usually do this if I need a single cycle delay:

asm("nop");

Be careful if you need to do it multipe times as it will be optimized and the results may be unexpected (assuming you are using optimization).

There is also:

__builtin_avr_delay_cycles(unsigned long __n);

The compiler will delay exactly as many cycles as you provide with the argument by inserting useless, and more importantly harmless, code. I usually see something like a string of subtracts, adds, etc.

On Sun, Jan 29, 2012 at 6:23 PM, Britton Kerin <address@hidden> wrote:

I notice the AVR Libc include/compat/ina90.h has this:

 #define _NOP() do { __asm__ __volatile__ ("nop"); } while (0)

but I didn't find anything else "nop"ish.  I generally don't include ina90.h.
Is there some good concise GCC/AVRLibc way to write nop that I missed?

Thanks,
Britton

_______________________________________________
AVR-chat mailing list
address@hidden
https://lists.nongnu.org/mailman/listinfo/avr-chat