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/**
* Many similar implementations exist. See for example libwsbm
* or the linux kernel include/atomic.h
*
* No copyright claimed on this file.
*
*/
#ifndef U_ATOMIC_H
#define U_ATOMIC_H
/* Favor OS-provided implementations.
*
* Where no OS-provided implementation is available, fall back to
* locally coded assembly, compiler intrinsic or ultimately a
* mutex-based implementation.
*/
#if defined(__sun)
#define PIPE_ATOMIC_OS_SOLARIS
#elif defined(_MSC_VER)
#define PIPE_ATOMIC_MSVC_INTRINSIC
#elif (defined(_MSC_VER) && (defined(__i386__) || defined(_M_IX86))
#define PIPE_ATOMIC_ASM_MSVC_X86
#elif defined(__GNUC__) && ((__GNUC__ * 100 + __GNUC_MINOR__) >= 401)
#define PIPE_ATOMIC_GCC_INTRINSIC
#elif (defined(__GNUC__) && defined(__i386__))
#define PIPE_ATOMIC_ASM_GCC_X86
#elif (defined(__GNUC__) && defined(__x86_64__))
#define PIPE_ATOMIC_ASM_GCC_X86_64
#else
#error "Unsupported platform"
#endif
#if defined(PIPE_ATOMIC_ASM_GCC_X86_64)
#define PIPE_ATOMIC "GCC x86_64 assembly"
#ifdef __cplusplus
extern "C" {
#endif
#define p_atomic_set(_v, _i) (*(_v) = (_i))
#define p_atomic_read(_v) (*(_v))
static inline boolean
p_atomic_dec_zero(int32_t *v)
{
unsigned char c;
__asm__ __volatile__("lock; decl %0; sete %1":"+m"(*v), "=qm"(c)
::"memory");
return c != 0;
}
static inline void
p_atomic_inc(int32_t *v)
{
__asm__ __volatile__("lock; incl %0":"+m"(*v));
}
static inline void
p_atomic_dec(int32_t *v)
{
__asm__ __volatile__("lock; decl %0":"+m"(*v));
}
static inline int32_t
p_atomic_inc_return(int32_t *v)
{
return __sync_add_and_fetch(v, 1);
}
static inline int32_t
p_atomic_dec_return(int32_t *v)
{
return __sync_sub_and_fetch(v, 1);
}
static inline int32_t
p_atomic_cmpxchg(int32_t *v, int32_t old, int32_t _new)
{
return __sync_val_compare_and_swap(v, old, _new);
}
#ifdef __cplusplus
}
#endif
#endif /* PIPE_ATOMIC_ASM_GCC_X86_64 */
#if defined(PIPE_ATOMIC_ASM_GCC_X86)
#define PIPE_ATOMIC "GCC x86 assembly"
#ifdef __cplusplus
extern "C" {
#endif
#define p_atomic_set(_v, _i) (*(_v) = (_i))
#define p_atomic_read(_v) (*(_v))
static inline boolean
p_atomic_dec_zero(int32_t *v)
{
unsigned char c;
__asm__ __volatile__("lock; decl %0; sete %1":"+m"(*v), "=qm"(c)
::"memory");
return c != 0;
}
static inline void
p_atomic_inc(int32_t *v)
{
__asm__ __volatile__("lock; incl %0":"+m"(*v));
}
static inline void
p_atomic_dec(int32_t *v)
{
__asm__ __volatile__("lock; decl %0":"+m"(*v));
}
static inline int32_t
p_atomic_inc_return(int32_t *v)
{
return __sync_add_and_fetch(v, 1);
}
static inline int32_t
p_atomic_dec_return(int32_t *v)
{
return __sync_sub_and_fetch(v, 1);
}
static inline int32_t
p_atomic_cmpxchg(int32_t *v, int32_t old, int32_t _new)
{
return __sync_val_compare_and_swap(v, old, _new);
}
#ifdef __cplusplus
}
#endif
#endif
/* Implementation using GCC-provided synchronization intrinsics
*/
#if defined(PIPE_ATOMIC_GCC_INTRINSIC)
#define PIPE_ATOMIC "GCC Sync Intrinsics"
#ifdef __cplusplus
extern "C" {
#endif
#define p_atomic_set(_v, _i) (*(_v) = (_i))
#define p_atomic_read(_v) (*(_v))
static inline boolean
p_atomic_dec_zero(int32_t *v)
{
return (__sync_sub_and_fetch(v, 1) == 0);
}
static inline void
p_atomic_inc(int32_t *v)
{
(void) __sync_add_and_fetch(v, 1);
}
static inline void
p_atomic_dec(int32_t *v)
{
(void) __sync_sub_and_fetch(v, 1);
}
static inline int32_t
p_atomic_inc_return(int32_t *v)
{
return __sync_add_and_fetch(v, 1);
}
static inline int32_t
p_atomic_dec_return(int32_t *v)
{
return __sync_sub_and_fetch(v, 1);
}
static inline int32_t
p_atomic_cmpxchg(int32_t *v, int32_t old, int32_t _new)
{
return __sync_val_compare_and_swap(v, old, _new);
}
#ifdef __cplusplus
}
#endif
#endif
/* Unlocked version for single threaded environments, such as some
* windows kernel modules.
*/
#if defined(PIPE_ATOMIC_OS_UNLOCKED)
#define PIPE_ATOMIC "Unlocked"
#define p_atomic_set(_v, _i) (*(_v) = (_i))
#define p_atomic_read(_v) (*(_v))
#define p_atomic_dec_zero(_v) ((boolean) --(*(_v)))
#define p_atomic_inc(_v) ((void) (*(_v))++)
#define p_atomic_dec(_v) ((void) (*(_v))--)
#define p_atomic_inc_return(_v) ((*(_v))++)
#define p_atomic_dec_return(_v) ((*(_v))--)
#define p_atomic_cmpxchg(_v, old, _new) (*(_v) == old ? *(_v) = (_new) : *(_v))
#endif
/* Locally coded assembly for MSVC on x86:
*/
#if defined(PIPE_ATOMIC_ASM_MSVC_X86)
#define PIPE_ATOMIC "MSVC x86 assembly"
#ifdef __cplusplus
extern "C" {
#endif
#define p_atomic_set(_v, _i) (*(_v) = (_i))
#define p_atomic_read(_v) (*(_v))
static inline boolean
p_atomic_dec_zero(int32_t *v)
{
unsigned char c;
__asm {
mov eax, [v]
lock dec dword ptr [eax]
sete byte ptr [c]
}
return c != 0;
}
static inline void
p_atomic_inc(int32_t *v)
{
__asm {
mov eax, [v]
lock inc dword ptr [eax]
}
}
static inline void
p_atomic_dec(int32_t *v)
{
__asm {
mov eax, [v]
lock dec dword ptr [eax]
}
}
static inline int32_t
p_atomic_cmpxchg(int32_t *v, int32_t old, int32_t _new)
{
int32_t orig;
__asm {
mov ecx, [v]
mov eax, [old]
mov edx, [_new]
lock cmpxchg [ecx], edx
mov [orig], eax
}
return orig;
}
#ifdef __cplusplus
}
#endif
#endif
#if defined(PIPE_ATOMIC_MSVC_INTRINSIC)
#define PIPE_ATOMIC "MSVC Intrinsics"
#include <intrin.h>
#pragma intrinsic(_InterlockedIncrement)
#pragma intrinsic(_InterlockedDecrement)
#pragma intrinsic(_InterlockedCompareExchange)
#ifdef __cplusplus
extern "C" {
#endif
#define p_atomic_set(_v, _i) (*(_v) = (_i))
#define p_atomic_read(_v) (*(_v))
static inline boolean
p_atomic_dec_zero(int32_t *v)
{
return _InterlockedDecrement((long *)v) == 0;
}
static inline void
p_atomic_inc(int32_t *v)
{
_InterlockedIncrement((long *)v);
}
static inline int32_t
p_atomic_inc_return(int32_t *v)
{
return _InterlockedIncrement((long *)v);
}
static inline void
p_atomic_dec(int32_t *v)
{
_InterlockedDecrement((long *)v);
}
static inline int32_t
p_atomic_dec_return(int32_t *v)
{
return _InterlockedDecrement((long *)v);
}
static inline int32_t
p_atomic_cmpxchg(int32_t *v, int32_t old, int32_t _new)
{
return _InterlockedCompareExchange((long *)v, _new, old);
}
#ifdef __cplusplus
}
#endif
#endif
#if defined(PIPE_ATOMIC_OS_SOLARIS)
#define PIPE_ATOMIC "Solaris OS atomic functions"
#include <atomic.h>
#ifdef __cplusplus
extern "C" {
#endif
#define p_atomic_set(_v, _i) (*(_v) = (_i))
#define p_atomic_read(_v) (*(_v))
static inline boolean
p_atomic_dec_zero(int32_t *v)
{
uint32_t n = atomic_dec_32_nv((uint32_t *) v);
return n != 0;
}
#define p_atomic_inc(_v) atomic_inc_32((uint32_t *) _v)
#define p_atomic_dec(_v) atomic_dec_32((uint32_t *) _v)
#define p_atomic_inc_return(_v) atomic_inc_32_nv((uint32_t *) _v)
#define p_atomic_dec_return(_v) atomic_dec_32_nv((uint32_t *) _v)
#define p_atomic_cmpxchg(_v, _old, _new) \
atomic_cas_32( (uint32_t *) _v, (uint32_t) _old, (uint32_t) _new)
#ifdef __cplusplus
}
#endif
#endif
#ifndef PIPE_ATOMIC
#error "No pipe_atomic implementation selected"
#endif
#endif /* U_ATOMIC_H */
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