diff options
Diffstat (limited to 'nsprpub/pr/include/pratom.h')
| -rw-r--r-- | nsprpub/pr/include/pratom.h | 198 |
1 files changed, 198 insertions, 0 deletions
diff --git a/nsprpub/pr/include/pratom.h b/nsprpub/pr/include/pratom.h new file mode 100644 index 0000000000..11a8aaedc9 --- /dev/null +++ b/nsprpub/pr/include/pratom.h @@ -0,0 +1,198 @@ +/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ +/* This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ + +/* GLOBAL FUNCTIONS: +** DESCRIPTION: +** PR Atomic operations +*/ + +#ifndef pratom_h___ +#define pratom_h___ + +#include "prtypes.h" +#include "prlock.h" + +PR_BEGIN_EXTERN_C + +/* +** FUNCTION: PR_AtomicIncrement +** DESCRIPTION: +** Atomically increment a 32 bit value. +** INPUTS: +** val: a pointer to the value to increment +** RETURN: +** the returned value is the result of the increment +*/ +NSPR_API(PRInt32) PR_AtomicIncrement(PRInt32 *val); + +/* +** FUNCTION: PR_AtomicDecrement +** DESCRIPTION: +** Atomically decrement a 32 bit value. +** INPUTS: +** val: a pointer to the value to decrement +** RETURN: +** the returned value is the result of the decrement +*/ +NSPR_API(PRInt32) PR_AtomicDecrement(PRInt32 *val); + +/* +** FUNCTION: PR_AtomicSet +** DESCRIPTION: +** Atomically set a 32 bit value. +** INPUTS: +** val: A pointer to a 32 bit value to be set +** newval: The newvalue to assign to val +** RETURN: +** Returns the prior value +*/ +NSPR_API(PRInt32) PR_AtomicSet(PRInt32 *val, PRInt32 newval); + +/* +** FUNCTION: PR_AtomicAdd +** DESCRIPTION: +** Atomically add a 32 bit value. +** INPUTS: +** ptr: a pointer to the value to increment +** val: value to be added +** RETURN: +** the returned value is the result of the addition +*/ +NSPR_API(PRInt32) PR_AtomicAdd(PRInt32 *ptr, PRInt32 val); + +/* +** MACRO: PR_ATOMIC_INCREMENT +** MACRO: PR_ATOMIC_DECREMENT +** MACRO: PR_ATOMIC_SET +** MACRO: PR_ATOMIC_ADD +** DESCRIPTION: +** Macro versions of the atomic operations. They may be implemented +** as compiler intrinsics. +** +** IMPORTANT NOTE TO NSPR MAINTAINERS: +** Implement these macros with compiler intrinsics only on platforms +** where the PR_AtomicXXX functions are truly atomic (i.e., where the +** configuration macro _PR_HAVE_ATOMIC_OPS is defined). Otherwise, +** the macros and functions won't be compatible and can't be used +** interchangeably. +*/ +#if defined(_WIN32) && !defined(_WIN32_WCE) && \ + (!defined(_MSC_VER) || (_MSC_VER >= 1310)) + +#include <intrin.h> + +#ifdef _MSC_VER +#pragma intrinsic(_InterlockedIncrement) +#pragma intrinsic(_InterlockedDecrement) +#pragma intrinsic(_InterlockedExchange) +#pragma intrinsic(_InterlockedExchangeAdd) +#endif + +#define PR_ATOMIC_INCREMENT(val) _InterlockedIncrement((long volatile *)(val)) +#define PR_ATOMIC_DECREMENT(val) _InterlockedDecrement((long volatile *)(val)) +#define PR_ATOMIC_SET(val, newval) \ + _InterlockedExchange((long volatile *)(val), (long)(newval)) +#define PR_ATOMIC_ADD(ptr, val) \ + (_InterlockedExchangeAdd((long volatile *)(ptr), (long)(val)) + (val)) + +#elif ((__GNUC__ > 4) || (__GNUC__ == 4 && __GNUC_MINOR__ >= 1)) && \ + ((defined(__APPLE__) && \ + (defined(__ppc__) || defined(__i386__) || defined(__x86_64__))) || \ + (defined(__linux__) && \ + ((defined(__i386__) && \ + defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_4)) || \ + defined(__ia64__) || defined(__x86_64__) || \ + defined(__powerpc__) || \ + (defined(__arm__) && \ + defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_4)) || \ + defined(__aarch64__) || defined(__alpha) || \ + (defined(__mips__) && \ + defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_4))))) + +/* + * Because the GCC manual warns that some processors may support + * reduced functionality of __sync_lock_test_and_set, we test for the + * processors that we believe support a full atomic exchange operation. + */ + +#define PR_ATOMIC_INCREMENT(val) __sync_add_and_fetch(val, 1) +#define PR_ATOMIC_DECREMENT(val) __sync_sub_and_fetch(val, 1) +#define PR_ATOMIC_SET(val, newval) __sync_lock_test_and_set(val, newval) +#define PR_ATOMIC_ADD(ptr, val) __sync_add_and_fetch(ptr, val) + +#else + +#define PR_ATOMIC_INCREMENT(val) PR_AtomicIncrement(val) +#define PR_ATOMIC_DECREMENT(val) PR_AtomicDecrement(val) +#define PR_ATOMIC_SET(val, newval) PR_AtomicSet(val, newval) +#define PR_ATOMIC_ADD(ptr, val) PR_AtomicAdd(ptr, val) + +#endif + +/* +** LIFO linked-list (stack) +*/ +typedef struct PRStackElemStr PRStackElem; + +struct PRStackElemStr { + PRStackElem *prstk_elem_next; /* next pointer MUST be at offset 0; + assembly language code relies on this */ +}; + +typedef struct PRStackStr PRStack; + +/* +** FUNCTION: PR_CreateStack +** DESCRIPTION: +** Create a stack, a LIFO linked list +** INPUTS: +** stack_name: a pointer to string containing the name of the stack +** RETURN: +** A pointer to the created stack, if successful, else NULL. +*/ +NSPR_API(PRStack *) PR_CreateStack(const char *stack_name); + +/* +** FUNCTION: PR_StackPush +** DESCRIPTION: +** Push an element on the top of the stack +** INPUTS: +** stack: pointer to the stack +** stack_elem: pointer to the stack element +** RETURN: +** None +*/ +NSPR_API(void) PR_StackPush(PRStack *stack, PRStackElem *stack_elem); + +/* +** FUNCTION: PR_StackPop +** DESCRIPTION: +** Remove the element on the top of the stack +** INPUTS: +** stack: pointer to the stack +** RETURN: +** A pointer to the stack element removed from the top of the stack, +** if non-empty, +** else NULL +*/ +NSPR_API(PRStackElem *) PR_StackPop(PRStack *stack); + +/* +** FUNCTION: PR_DestroyStack +** DESCRIPTION: +** Destroy the stack +** INPUTS: +** stack: pointer to the stack +** RETURN: +** PR_SUCCESS - if successfully deleted +** PR_FAILURE - if the stack is not empty +** PR_GetError will return +** PR_INVALID_STATE_ERROR - stack is not empty +*/ +NSPR_API(PRStatus) PR_DestroyStack(PRStack *stack); + +PR_END_EXTERN_C + +#endif /* pratom_h___ */ |