return q;
}
+
+/**
+ @Begin
+ @Interface_define: Take
+ @End
+*/
int take(Deque *q) {
size_t b = atomic_load_explicit(&q->bottom, memory_order_relaxed) - 1;
Array *a = (Array *) atomic_load_explicit(&q->array, memory_order_relaxed);
atomic_store_explicit(&q->bottom, b, memory_order_relaxed);
atomic_thread_fence(memory_order_seq_cst);
size_t t = atomic_load_explicit(&q->top, memory_order_relaxed);
+ /**
+ @Begin
+ @Commit_point_define_check: t > b
+ @Label: Take_Point_1
+ @End
+ */
int x;
if (t <= b) {
/* Non-empty queue. */
- x = atomic_load_explicit(&a->buffer[b % atomic_load_explicit(&a->size,memory_order_relaxed)], memory_order_relaxed);
+ int size = atomic_load_explicit(&a->size,memory_order_relaxed);
+ x = atomic_load_explicit(&a->buffer[b % size], memory_order_relaxed);
+ /**
+ @Begin
+ @Commit_point_define_check: t != b
+ @Label: Take_Point2
+ @End
+ */
if (t == b) {
/* Single last element in queue. */
- if (!atomic_compare_exchange_strong_explicit(&q->top, &t, t + 1, memory_order_seq_cst, memory_order_relaxed))
+ //FIXME: weaken the following seq_cst causes no spec problem
+ bool succ = atomic_compare_exchange_strong_explicit(&q->top, &t, t +
+ 1, memory_order_seq_cst, memory_order_relaxed);
+ /**
+ @Begin
+ @Commit_point_define_check: true
+ @Label: Take_Point3
+ @End
+ */
+ if (!succ) {
/* Failed race. */
x = EMPTY;
+ }
atomic_store_explicit(&q->bottom, b + 1, memory_order_relaxed);
}
} else { /* Empty queue. */
for(i=top; i < bottom; i++) {
atomic_store_explicit(&new_a->buffer[i % new_size], atomic_load_explicit(&a->buffer[i % size], memory_order_relaxed), memory_order_relaxed);
}
+ /**** FIXME: detected failure ****/
atomic_store_explicit(&q->array, new_a, memory_order_release);
printf("resize\n");
}
+/**
+ @Begin
+ @Interface_define: Push
+ @End
+*/
void push(Deque *q, int x) {
size_t b = atomic_load_explicit(&q->bottom, memory_order_relaxed);
+ /**** FIXME: detected correctness ****/
size_t t = atomic_load_explicit(&q->top, memory_order_acquire);
Array *a = (Array *) atomic_load_explicit(&q->array, memory_order_relaxed);
if (b - t > atomic_load_explicit(&a->size, memory_order_relaxed) - 1) /* Full queue. */ {
//Bug in paper...should have next line...
a = (Array *) atomic_load_explicit(&q->array, memory_order_relaxed);
}
- atomic_store_explicit(&a->buffer[b % atomic_load_explicit(&a->size, memory_order_relaxed)], x, memory_order_relaxed);
+ int size = atomic_load_explicit(&a->size, memory_order_relaxed);
+ atomic_store_explicit(&a->buffer[b % size], x, memory_order_relaxed);
+ /**
+ @Begin
+ @Commit_point_define_check: true
+ @Label: Push_Point
+ @End
+ */
atomic_thread_fence(memory_order_release);
+
atomic_store_explicit(&q->bottom, b + 1, memory_order_relaxed);
+
}
+/**
+ @Begin
+ @Interface_define: Steal
+ @End
+*/
int steal(Deque *q) {
+ //FIXME: weaken the following acquire causes no spec problem
size_t t = atomic_load_explicit(&q->top, memory_order_acquire);
atomic_thread_fence(memory_order_seq_cst);
size_t b = atomic_load_explicit(&q->bottom, memory_order_acquire);
+ /**
+ @Begin
+ @Commit_point_define_check: t >= b
+ @Label: Steal_Point1
+ @End
+ */
int x = EMPTY;
if (t < b) {
/* Non-empty queue. */
Array *a = (Array *) atomic_load_explicit(&q->array, memory_order_acquire);
- x = atomic_load_explicit(&a->buffer[t % atomic_load_explicit(&a->size, memory_order_relaxed)], memory_order_relaxed);
- if (!atomic_compare_exchange_strong_explicit(&q->top, &t, t + 1, memory_order_seq_cst, memory_order_relaxed))
+ int size = atomic_load_explicit(&a->size, memory_order_relaxed);
+ x = atomic_load_explicit(&a->buffer[t % size], memory_order_relaxed);
+ /**
+ @Begin
+ @Potential_commit_point_define: true
+ @Label: Potential_Steal
+ @End
+ */
+
+ bool succ = atomic_compare_exchange_strong_explicit(&q->top, &t, t + 1,
+ memory_order_seq_cst, memory_order_relaxed);
+ /**
+ @Begin
+ @Commit_point_define_check: !succ
+ @Label: Steal_Point2
+ @End
+ */
+
+ /**
+ @Begin
+ @Commit_point_define: succ
+ @Potential_commit_point_label: Potential_Steal
+ @Label: Steal_Point3
+ @End
+ */
+ if (!succ) {
/* Failed race. */
return ABORT;
+ }
}
return x;
}