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);
20 @Interface_define: Take
24 size_t b = atomic_load_explicit(&q->bottom, memory_order_relaxed) - 1;
25 Array *a = (Array *) atomic_load_explicit(&q->array, memory_order_relaxed);
26 atomic_store_explicit(&q->bottom, b, memory_order_relaxed);
27 /**** detected correctness ****/
28 atomic_thread_fence(memory_order_seq_cst);
29 size_t t = atomic_load_explicit(&q->top, memory_order_relaxed);
32 @Commit_point_define_check: t > b
38 /* Non-empty queue. */
39 int size = atomic_load_explicit(&a->size,memory_order_relaxed);
40 x = atomic_load_explicit(&a->buffer[b % size], memory_order_relaxed);
43 @Commit_point_define_check: t != b
48 /* Single last element in queue. */
49 //FIXME: weaken the following seq_cst causes no spec problem
50 bool succ = atomic_compare_exchange_strong_explicit(&q->top, &t, t +
51 1, memory_order_seq_cst, memory_order_relaxed);
54 @Commit_point_define_check: true
62 atomic_store_explicit(&q->bottom, b + 1, memory_order_relaxed);
64 } else { /* Empty queue. */
66 atomic_store_explicit(&q->bottom, b + 1, memory_order_relaxed);
71 void resize(Deque *q) {
72 Array *a = (Array *) atomic_load_explicit(&q->array, memory_order_relaxed);
73 size_t size=atomic_load_explicit(&a->size, memory_order_relaxed);
74 size_t new_size=size << 1;
75 Array *new_a = (Array *) calloc(1, new_size * sizeof(atomic_int) + sizeof(Array));
76 size_t top=atomic_load_explicit(&q->top, memory_order_relaxed);
77 size_t bottom=atomic_load_explicit(&q->bottom, memory_order_relaxed);
78 atomic_store_explicit(&new_a->size, new_size, memory_order_relaxed);
80 for(i=top; i < bottom; i++) {
81 atomic_store_explicit(&new_a->buffer[i % new_size], atomic_load_explicit(&a->buffer[i % size], memory_order_relaxed), memory_order_relaxed);
83 /**** detected UL ****/
84 atomic_store_explicit(&q->array, new_a, memory_order_release);
90 @Interface_define: Push
93 void push(Deque *q, int x) {
94 size_t b = atomic_load_explicit(&q->bottom, memory_order_relaxed);
95 /**** detected correctness ****/
96 size_t t = atomic_load_explicit(&q->top, memory_order_acquire);
97 Array *a = (Array *) atomic_load_explicit(&q->array, memory_order_relaxed);
98 if (b - t > atomic_load_explicit(&a->size, memory_order_relaxed) - 1) /* Full queue. */ {
100 //Bug in paper...should have next line...
101 a = (Array *) atomic_load_explicit(&q->array, memory_order_relaxed);
104 @Commit_point_define_check: true
105 @Label: Push_Read_Array
109 int size = atomic_load_explicit(&a->size, memory_order_relaxed);
111 atomic_store_explicit(&a->buffer[b % size], x, memory_order_relaxed);
114 @Commit_point_define_check: true
115 @Label: Push_Update_Buffer
118 /**** correctness error ****/
119 atomic_thread_fence(memory_order_release);
121 atomic_store_explicit(&q->bottom, b + 1, memory_order_relaxed);
124 @Commit_point_define_check: true
125 @Label: Push_Update_Bottom
132 @Interface_define: Steal
135 int steal(Deque *q) {
136 //FIXME: weaken the following acquire causes no spec problem
137 size_t t = atomic_load_explicit(&q->top, memory_order_acquire);
138 //FIXME: remove the fence causes no error and fewer executions..
139 atomic_thread_fence(memory_order_seq_cst);
140 /**** detected UL ****/
141 size_t b = atomic_load_explicit(&q->bottom, memory_order_acquire);
144 @Commit_point_define_check: t >= b
150 /* Non-empty queue. */
151 /**** detected UL ****/
152 Array *a = (Array *) atomic_load_explicit(&q->array, memory_order_acquire);
153 int size = atomic_load_explicit(&a->size, memory_order_relaxed);
154 x = atomic_load_explicit(&a->buffer[t % size], memory_order_relaxed);
157 @Potential_commit_point_define: true
158 @Label: Potential_Steal
161 /**** detected correctness failure ****/
162 bool succ = atomic_compare_exchange_strong_explicit(&q->top, &t, t + 1,
163 memory_order_seq_cst, memory_order_relaxed);
166 @Commit_point_define_check: !succ
173 @Commit_point_define: succ
174 @Potential_commit_point_label: Potential_Steal