...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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