fusl/src/thread/__wait.c

#include "pthread_impl.h"

void __wait(volatile int* addr, volatile int* waiters, int val, int priv) {
  int spins = 100;
  if (priv)
    priv = FUTEX_PRIVATE;
  while (spins-- && (!waiters || !*waiters)) {
    if (*addr == val)
      a_spin();
    else
      return;
  }
  if (waiters)
    a_inc(waiters);
  while (*addr == val) {
    __syscall(SYS_futex, addr, FUTEX_WAIT | priv, val, 0) != -ENOSYS ||
        __syscall(SYS_futex, addr, FUTEX_WAIT, val, 0);
  }
  if (waiters)
    a_dec(waiters);
}