8 Deque * q = (Deque *) calloc(1, sizeof(Deque));
9 Array * a = (Array *) calloc(1, sizeof(Array)+2*sizeof(atomic_int));
10 atomic_store_explicit(&q->array, a, memory_order_relaxed);
11 atomic_store_explicit(&q->top, 0, memory_order_relaxed);
12 atomic_store_explicit(&q->bottom, 0, memory_order_relaxed);
13 atomic_store_explicit(&a->size, 2, memory_order_relaxed);
18 size_t b = atomic_load_explicit(&q->bottom, memory_order_relaxed) - 1;
19 Array *a = (Array *) atomic_load_explicit(&q->array, memory_order_relaxed);
20 atomic_store_explicit(&q->bottom, b, memory_order_relaxed);
21 atomic_thread_fence(memory_order_seq_cst);
22 size_t t = atomic_load_explicit(&q->top, memory_order_relaxed);
25 /* Non-empty queue. */
26 x = atomic_load_explicit(&a->buffer[b % atomic_load_explicit(&a->size,memory_order_relaxed)], memory_order_relaxed);
28 /* Single last element in queue. */
29 if (!atomic_compare_exchange_strong_explicit(&q->top, &t, t + 1, memory_order_seq_cst, memory_order_relaxed))
32 atomic_store_explicit(&q->bottom, b + 1, memory_order_relaxed);
34 } else { /* Empty queue. */
36 atomic_store_explicit(&q->bottom, b + 1, memory_order_relaxed);
41 void resize(Deque *q) {
42 Array *a = (Array *) atomic_load_explicit(&q->array, memory_order_relaxed);
43 size_t size=atomic_load_explicit(&a->size, memory_order_relaxed);
44 size_t new_size=size << 1;
45 Array *new_a = (Array *) calloc(1, new_size * sizeof(atomic_int) + sizeof(Array));
46 size_t top=atomic_load_explicit(&q->top, memory_order_relaxed);
47 size_t bottom=atomic_load_explicit(&q->bottom, memory_order_relaxed);
48 atomic_store_explicit(&new_a->size, new_size, memory_order_relaxed);
50 for(i=top; i < bottom; i++) {
51 atomic_store_explicit(&new_a->buffer[i % new_size], atomic_load_explicit(&a->buffer[i % size], memory_order_relaxed), memory_order_relaxed);
53 atomic_store_explicit(&q->array, new_a, memory_order_relaxed);
57 void push(Deque *q, int x) {
58 size_t b = atomic_load_explicit(&q->bottom, memory_order_relaxed);
59 size_t t = atomic_load_explicit(&q->top, memory_order_acquire);
60 Array *a = (Array *) atomic_load_explicit(&q->array, memory_order_relaxed);
61 if (b - t > atomic_load_explicit(&a->size, memory_order_relaxed) - 1) /* Full queue. */ {
63 //Bug in paper...should have next line...
64 a = (Array *) atomic_load_explicit(&q->array, memory_order_relaxed);
66 atomic_store_explicit(&a->buffer[b % atomic_load_explicit(&a->size, memory_order_relaxed)], x, memory_order_relaxed);
67 atomic_thread_fence(memory_order_release);
68 atomic_store_explicit(&q->bottom, b + 1, memory_order_relaxed);
72 size_t t = atomic_load_explicit(&q->top, memory_order_acquire);
73 atomic_thread_fence(memory_order_seq_cst);
74 size_t b = atomic_load_explicit(&q->bottom, memory_order_acquire);
77 /* Non-empty queue. */
78 Array *a = (Array *) atomic_load_explicit(&q->array, memory_order_relaxed);
79 x = atomic_load_explicit(&a->buffer[t % atomic_load_explicit(&a->size, memory_order_relaxed)], memory_order_relaxed);
80 if (!atomic_compare_exchange_strong_explicit(&q->top, &t, t + 1, memory_order_seq_cst, memory_order_relaxed))