Well. There was nothing in there that showed me that afterstart == 0. Is
this a known fact, or an assumption?
Johnny
On 2021-03-24 21:47, Grr wrote:
Since afterstart = 0, there should be no loop to optimize out except ONE
value test
One hundred cycles for that would seem excessive for me
TWENTY THOUSAND CYCLES for a _zero_ loop?!?
Maybe in Java
El mié, 24 mar 2021 a las 14:30, Gregory Nutt (<spudan...@gmail.com>)
escribió:
Weird behavior:
Simply changing loop counter variable from uint16_t to volatile uint16_t
causes initial delay (with variable delay = 0) going from ~500 ns to
~120 us
The code is
uint16_t delay;
select_function();
for(delay = 0; delay < transfer->dev->afterstart; delay++);
Any ideas?
I imagine that the delay loop is no longer being optimized out. That is
what volatile is supposed to do (people often don't understand that, it
is a great interview question).
--
Johnny Billquist || "I'm on a bus
|| on a psychedelic trip
email: b...@softjar.se || Reading murder books
pdp is alive! || tryin' to stay hip" - B. Idol
