7 Deque * q = (Deque *) calloc(1, sizeof(Deque));
8 Array * a = (Array *) calloc(1, sizeof(Array)+2*sizeof(atomic_int));
9 atomic_store_explicit(&q->array, a, memory_order_relaxed);
10 atomic_store_explicit(&q->top, 0, memory_order_relaxed);
11 atomic_store_explicit(&q->bottom, 0, memory_order_relaxed);
12 atomic_store_explicit(&a->size, 2, memory_order_relaxed);
17 size_t b = atomic_load_explicit(&q->bottom, memory_order_relaxed) - 1;
18 Array *a = (Array *) atomic_load_explicit(&q->array, memory_order_relaxed);
19 atomic_store_explicit(&q->bottom, b, memory_order_relaxed);
20 atomic_thread_fence(memory_order_seq_cst);
21 size_t t = atomic_load_explicit(&q->top, memory_order_relaxed);
24 /* Non-empty queue. */
25 x = atomic_load_explicit(&a->buffer[b % atomic_load_explicit(&a->size,memory_order_relaxed)], memory_order_relaxed);
27 /* Single last element in queue. */
28 if (!atomic_compare_exchange_strong_explicit(&q->top, &t, t + 1, memory_order_seq_cst, memory_order_relaxed))
31 atomic_store_explicit(&q->bottom, b + 1, memory_order_relaxed);
33 } else { /* Empty queue. */
35 atomic_store_explicit(&q->bottom, b + 1, memory_order_relaxed);
40 void resize(Deque *q) {
41 Array *a = (Array *) atomic_load_explicit(&q->array, memory_order_relaxed);
42 size_t size=atomic_load_explicit(&a->size, memory_order_relaxed);
43 size_t new_size=size << 1;
44 Array *new_a = (Array *) calloc(1, new_size * sizeof(atomic_int) + sizeof(Array));
45 size_t top=atomic_load_explicit(&q->top, memory_order_relaxed);
46 size_t bottom=atomic_load_explicit(&q->bottom, memory_order_relaxed);
47 atomic_store_explicit(&new_a->size, new_size, memory_order_relaxed);
49 for(i=top; i < bottom; i++) {
50 atomic_store_explicit(&new_a->buffer[i % new_size], atomic_load_explicit(&a->buffer[i % size], memory_order_relaxed), memory_order_relaxed);
52 atomic_store_explicit(&q->array, new_a, memory_order_relaxed);
55 void push(Deque *q, int x) {
56 size_t b = atomic_load_explicit(&q->bottom, memory_order_relaxed);
57 size_t t = atomic_load_explicit(&q->top, memory_order_acquire);
58 Array *a = (Array *) atomic_load_explicit(&q->array, memory_order_relaxed);
59 if (b - t > atomic_load_explicit(&a->size, memory_order_relaxed) - 1) /* Full queue. */ {
61 //Bug in paper...should have next line...
62 a = (Array *) atomic_load_explicit(&q->array, memory_order_relaxed);
64 atomic_store_explicit(&a->buffer[b % atomic_load_explicit(&a->size, memory_order_relaxed)], x, memory_order_relaxed);
65 atomic_thread_fence(memory_order_release);
66 atomic_store_explicit(&q->bottom, b + 1, memory_order_relaxed);
70 size_t t = atomic_load_explicit(&q->top, memory_order_acquire);
71 atomic_thread_fence(memory_order_seq_cst);
72 size_t b = atomic_load_explicit(&q->bottom, memory_order_acquire);
75 /* Non-empty queue. */
76 Array *a = (Array *) atomic_load_explicit(&q->array, memory_order_relaxed);
77 x = atomic_load_explicit(&a->buffer[t % atomic_load_explicit(&a->size, memory_order_relaxed)], memory_order_relaxed);
78 if (!atomic_compare_exchange_strong_explicit(&q->top, &t, t + 1, memory_order_seq_cst, memory_order_relaxed))