#include "pthread_impl.h"

static volatile int vmlock[2];

void __vm_wait() {
  int tmp;
  while ((tmp = vmlock[0]))
    __wait(vmlock, vmlock + 1, tmp, 1);
}

void __vm_lock() {
  a_inc(vmlock);
}

void __vm_unlock() {
  if (a_fetch_add(vmlock, -1) == 1 && vmlock[1])
    __wake(vmlock, -1, 1);
}