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