-typedef struct {
- atomic_size_t size;
- atomic_int buffer[];
-} Array;
+#include <stdatomic.h>
+#include <inttypes.h>
+#include "deque.h"
+#include <stdlib.h>
+#include <stdio.h>
-typedef struct {
- atomic_size_t top, bottom;
- Atomic(Array *) array;
-} Deque;
+Deque * create() {
+ Deque * q = (Deque *) calloc(1, sizeof(Deque));
+ Array * a = (Array *) calloc(1, sizeof(Array)+2*sizeof(atomic_int));
+ atomic_store_explicit(&q->array, a, memory_order_relaxed);
+ atomic_store_explicit(&q->top, 0, memory_order_relaxed);
+ atomic_store_explicit(&q->bottom, 0, memory_order_relaxed);
+ atomic_store_explicit(&a->size, 2, memory_order_relaxed);
+ return q;
+}
int take(Deque *q) {
- size_t b = load_explicit(&q->bottom, relaxed) - 1;
- Array *a = load_explicit(&q->array, relaxed);
- store_explicit(&q->bottom, b, relaxed);
- thread_fence(seq_cst);
- size_t t = load_explicit(&q->top, relaxed);
+ 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);
int x;
if (t <= b) {
/* Non-empty queue. */
- x = load_explicit(&a->buffer[b % a->size], relaxed);
+ x = atomic_load_explicit(&a->buffer[b % atomic_load_explicit(&a->size,memory_order_relaxed)], memory_order_relaxed);
if (t == b) {
/* Single last element in queue. */
- if (!compare_exchange_strong_explicit(&q->top, &t, t + 1, seq_cst, relaxed))
+ if (!atomic_compare_exchange_strong_explicit(&q->top, &t, t + 1, memory_order_seq_cst, memory_order_relaxed))
/* Failed race. */
x = EMPTY;
- store_explicit(&q->bottom, b + 1, relaxed);
+ atomic_store_explicit(&q->bottom, b + 1, memory_order_relaxed);
}
} else { /* Empty queue. */
x = EMPTY;
- store_explicit(&q->bottom, b + 1, relaxed);
+ atomic_store_explicit(&q->bottom, b + 1, memory_order_relaxed);
}
return x;
}
+void resize(Deque *q) {
+ Array *a = (Array *) atomic_load_explicit(&q->array, memory_order_relaxed);
+ size_t size=atomic_load_explicit(&a->size, memory_order_relaxed);
+ size_t new_size=size << 1;
+ Array *new_a = (Array *) calloc(1, new_size * sizeof(atomic_int) + sizeof(Array));
+ size_t top=atomic_load_explicit(&q->top, memory_order_relaxed);
+ size_t bottom=atomic_load_explicit(&q->bottom, memory_order_relaxed);
+ atomic_store_explicit(&new_a->size, new_size, memory_order_relaxed);
+ size_t i;
+ 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);
+ }
+ atomic_store_explicit(&q->array, new_a, memory_order_relaxed);
+ printf("resize\n");
+}
+
void push(Deque *q, int x) {
- size_t b = load_explicit(&q->bottom, relaxed);
- size_t t = load_explicit(&q->top, acquire);
- Array *a = load_explicit(&q->array, relaxed);
- if (b - t > a->size - 1) /* Full queue. */
+ size_t b = atomic_load_explicit(&q->bottom, memory_order_relaxed);
+ 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. */ {
resize(q);
- store_explicit(&a->buffer[b % a->size], x, relaxed);
- thread_fence(release);
- store_explicit(&q->bottom, b + 1, relaxed);
+ //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);
+ atomic_thread_fence(memory_order_release);
+ atomic_store_explicit(&q->bottom, b + 1, memory_order_relaxed);
}
int steal(Deque *q) {
- size_t t = load_explicit(&q->top, acquire);
- thread_fence(seq_cst);
- size_t b = load_explicit(&q->bottom, acquire);
+ 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);
int x = EMPTY;
if (t < b) {
/* Non-empty queue. */
- Array *a = load_explicit(&q->array, relaxed);
- x = load_explicit(&a->buffer[t % a->size], relaxed);
- if (!compare_exchange_strong_explicit(&q->top, &t, t + 1, seq_cst, relaxed))
+ Array *a = (Array *) atomic_load_explicit(&q->array, memory_order_relaxed);
+ 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))
/* Failed race. */
return ABORT;
}