1 b2cfc4e2 2003-09-30 devnull #include <unistd.h>
2 b2cfc4e2 2003-09-30 devnull #include <sched.h>
3 b2cfc4e2 2003-09-30 devnull #include <lib9.h>
5 b2cfc4e2 2003-09-30 devnull int _ntas;
6 b2cfc4e2 2003-09-30 devnull static int
7 b2cfc4e2 2003-09-30 devnull _xtas(void *v)
12 b2cfc4e2 2003-09-30 devnull x = _tas(v);
13 a995e477 2003-10-01 devnull return x;
17 b2cfc4e2 2003-09-30 devnull canlock(Lock *l)
19 b2cfc4e2 2003-09-30 devnull return !_xtas(&l->val);
23 b2cfc4e2 2003-09-30 devnull unlock(Lock *l)
25 b2cfc4e2 2003-09-30 devnull l->val = 0;
29 b2cfc4e2 2003-09-30 devnull lock(Lock *lk)
33 b2cfc4e2 2003-09-30 devnull /* once fast */
34 b2cfc4e2 2003-09-30 devnull if(!_xtas(&lk->val))
36 b2cfc4e2 2003-09-30 devnull /* a thousand times pretty fast */
37 b2cfc4e2 2003-09-30 devnull for(i=0; i<1000; i++){
38 b2cfc4e2 2003-09-30 devnull if(!_xtas(&lk->val))
40 b2cfc4e2 2003-09-30 devnull sched_yield();
42 b2cfc4e2 2003-09-30 devnull /* now nice and slow */
43 b2cfc4e2 2003-09-30 devnull for(i=0; i<1000; i++){
44 b2cfc4e2 2003-09-30 devnull if(!_xtas(&lk->val))
46 b2cfc4e2 2003-09-30 devnull usleep(100*1000);
48 b2cfc4e2 2003-09-30 devnull /* take your time */
49 b2cfc4e2 2003-09-30 devnull while(_xtas(&lk->val))
50 b2cfc4e2 2003-09-30 devnull usleep(1000*1000);