source: CIVL/examples/openMP/omp.cvh@ 83c054c

// global variables and procedures shared by all threads.

/********************* functions provided by omp.h *************/
$input int OMP_NUM_THREADS;
int in_barrier[OMP_NUM_THREADS];
int num_in_barrier = 0;

int omp_get_num_threads() {
  return OMP_NUM_THREADS;
}

/********************* helper functions for translation *************/

/* Common functions for translating for loops */
// computes the start index for a given thread
int __for_start(int tid, int total) {
  return ((total/OMP_NUM_THREADS) * tid);
}

//computes the end index for a given thread
int __for_end(int tid, int total) {
  return ((total/OMP_NUM_THREADS) * (tid + 1));
}

//computes the extra index for a given thread
int __for_extra(int tid, int total) {
  int offset = total % OMP_NUM_THREADS;
  
  if(tid < offset) {
    return total - offset + tid;
  }
  return 0;
}

/********************* barrier implementation *************/

void __barrier_init() {
  for (int i=0; i<OMP_NUM_THREADS; i++) in_barrier[i] = 0;
}
   
// model the synchronization of threads in the same block
void __barrier(int tid) {
  $atomic {
  in_barrier[tid] = 1; // I am in the barrier
    num_in_barrier++; // increment number in barrier
    if (num_in_barrier == OMP_NUM_THREADS) { // I am last to enter
      for (int i=0; i<OMP_NUM_THREADS; i++) in_barrier[i] = 0; // release all
        num_in_barrier = 0; // now none are in barrier
      }
    }
    $when (in_barrier[tid] == 0); // wait till I am released
  }