check for fpu usage?

["alexander w. fiedel" <alexander.w.fiedel@web.de>]

...another one of thoose beginners questions...

hi.
I want to check if my fpu is working - and if it is really
useful to use it (also timing tests for the protocoll...)
I wrote a short loop with calcs, activate the fpu, compute
and measure the results (with d/a card and oscilloscope).
the time results are always the same - with or without fpu
enabled.
about 14us...

has anyone an idea?! or is this again a typical beginners
fault in thinking...

I use rtlinux3, kernel 2.2.18 and PIII 1GHz.
thanks!

---

the loop (with cos, mul and sqrt), used in "task_one()":

for (i=0;i<=35;i++){
	output*=(cos(output)*3.23458);
	output*=(cos(2.578*output));
	output=sqrt(output);
}



---

measurement method:
1. use d/a ch1 for defined signal
2. compute calcs and send them to d/a ch.2
3. use d/a ch3 for same signal as in 1.
4. measure timeshift between 1. and 3.
 - should be fine.

---

init code:

int init_module (void){
	pthread_attr_t attr; 
	pthread_attr_init(&attr);  
	pthread_attr_setfp_np(&attr, 1); 
	pthread_create (&mythread, &attr, task_one,0);
	return 0;
}

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