+++ /dev/null
-/*
- * The implementation of the routines described here is covered by the GPL.
- * This header file is covered by the following license:
- */
-
-/*
- * Copyright (c) 2005 Hewlett-Packard Development Company, L.P.
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to deal
- * in the Software without restriction, including without limitation the rights
- * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
- * SOFTWARE.
- */
-
-/* Almost lock-free LIFO linked lists (linked stacks). */
-#ifndef AO_STACK_H
-#define AO_STACK_H
-
-#include "atomic_ops.h"
-
-#if !defined(AO_HAVE_compare_double_and_swap_double) \
- && !defined(AO_HAVE_compare_double_and_swap) \
- && defined(AO_HAVE_compare_and_swap)
-# define AO_USE_ALMOST_LOCK_FREE
-#else
- /* If we have no compare-and-swap operation defined, we assume */
- /* that we will actually be using CAS emulation. If we do that, */
- /* it's cheaper to use the version-based implementation. */
-# define AO_STACK_IS_LOCK_FREE
-#endif
-
-/*
- * These are not guaranteed to be completely lock-free.
- * List insertion may spin under extremely unlikely conditions.
- * It cannot deadlock due to recursive reentry unless AO_list_remove
- * is called while at least AO_BL_SIZE activations of
- * AO_list_remove are currently active in the same thread, i.e.
- * we must have at least AO_BL_SIZE recursive signal handler
- * invocations.
- *
- * All operations take an AO_list_aux argument. It is safe to
- * share a single AO_list_aux structure among all lists, but that
- * may increase contention. Any given list must always be accessed
- * with the same AO_list_aux structure.
- *
- * We make some machine-dependent assumptions:
- * - We have a compare-and-swap operation.
- * - At least _AO_N_BITS low order bits in pointers are
- * zero and normally unused.
- * - size_t and pointers have the same size.
- *
- * We do use a fully lock-free implementation if double-width
- * compare-and-swap operations are available.
- */
-
-#ifdef AO_USE_ALMOST_LOCK_FREE
-/* The number of low order pointer bits we can use for a small */
-/* version number. */
-# if defined(__LP64__) || defined(_LP64) || defined(_WIN64)
- /* WIN64 isn't really supported yet. */
-# define AO_N_BITS 3
-# else
-# define AO_N_BITS 2
-# endif
-
-# define AO_BIT_MASK ((1 << AO_N_BITS) - 1)
-/*
- * AO_stack_aux should be treated as opaque.
- * It is fully defined here, so it can be allocated, and to facilitate
- * debugging.
- */
-#ifndef AO_BL_SIZE
-# define AO_BL_SIZE 2
-#endif
-
-#if AO_BL_SIZE > (1 << AO_N_BITS)
-# error AO_BL_SIZE too big
-#endif
-
-typedef struct AO__stack_aux {
- volatile AO_t AO_stack_bl[AO_BL_SIZE];
-} AO_stack_aux;
-
-/* The stack implementation knows only about the location of */
-/* link fields in nodes, and nothing about the rest of the */
-/* stack elements. Link fields hold an AO_t, which is not */
-/* necessarily a real pointer. This converts the AO_t to a */
-/* real (AO_t *) which is either o, or points at the link */
-/* field in the next node. */
-#define AO_REAL_NEXT_PTR(x) (AO_t *)((x) & ~AO_BIT_MASK)
-
-/* The following two routines should not normally be used directly. */
-/* We make them visible here for the rare cases in which it makes sense */
-/* to share the an AO_stack_aux between stacks. */
-void
-AO_stack_push_explicit_aux_release(volatile AO_t *list, AO_t *x,
- AO_stack_aux *);
-
-AO_t *
-AO_stack_pop_explicit_aux_acquire(volatile AO_t *list, AO_stack_aux *);
-
-/* And now AO_stack_t for the real interface: */
-
-typedef struct AO__stack {
- volatile AO_t AO_ptr;
- AO_stack_aux AO_aux;
-} AO_stack_t;
-
-#define AO_STACK_INITIALIZER {0}
-
-AO_INLINE void AO_stack_init(AO_stack_t *list)
-{
-# if AO_BL_SIZE == 2
- list -> AO_aux.AO_stack_bl[0] = 0;
- list -> AO_aux.AO_stack_bl[1] = 0;
-# else
- int i;
- for (i = 0; i < AO_BL_SIZE; ++i)
- list -> AO_aux.AO_stack_bl[i] = 0;
-# endif
- list -> AO_ptr = 0;
-}
-
-/* Convert an AO_stack_t to a pointer to the link field in */
-/* the first element. */
-#define AO_REAL_HEAD_PTR(x) AO_REAL_NEXT_PTR((x).AO_ptr)
-
-#define AO_stack_push_release(l, e) \
- AO_stack_push_explicit_aux_release(&((l)->AO_ptr), e, &((l)->AO_aux))
-#define AO_HAVE_stack_push_release
-
-#define AO_stack_pop_acquire(l) \
- AO_stack_pop_explicit_aux_acquire(&((l)->AO_ptr), &((l)->AO_aux))
-#define AO_HAVE_stack_pop_acquire
-
-# else /* Use fully non-blocking data structure, wide CAS */
-
-#ifndef AO_HAVE_double_t
- /* Can happen if we're using CAS emulation, since we don't want to */
- /* force that here, in case other atomic_ops clients don't want it. */
-# include "atomic_ops/sysdeps/standard_ao_double_t.h"
-#endif
-
-typedef volatile AO_double_t AO_stack_t;
-/* AO_val1 is version, AO_val2 is pointer. */
-
-#define AO_STACK_INITIALIZER {0}
-
-AO_INLINE void AO_stack_init(AO_stack_t *list)
-{
- list -> AO_val1 = 0;
- list -> AO_val2 = 0;
-}
-
-#define AO_REAL_HEAD_PTR(x) (AO_t *)((x).AO_val2)
-#define AO_REAL_NEXT_PTR(x) (AO_t *)(x)
-
-void AO_stack_push_release(AO_stack_t *list, AO_t *new_element);
-#define AO_HAVE_stack_push_release
-AO_t * AO_stack_pop_acquire(AO_stack_t *list);
-#define AO_HAVE_stack_pop_acquire
-
-#endif /* Wide CAS case */
-
-#if defined(AO_HAVE_stack_push_release) && !defined(AO_HAVE_stack_push)
-# define AO_stack_push(l, e) AO_stack_push_release(l, e)
-# define AO_HAVE_stack_push
-#endif
-
-#if defined(AO_HAVE_stack_pop_acquire) && !defined(AO_HAVE_stack_pop)
-# define AO_stack_pop(l) AO_stack_pop_acquire(l)
-# define AO_HAVE_stack_pop
-#endif
-
-#endif /* !AO_STACK_H */
projects / cacao.git / blobdiff