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SDL_atomic.h
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1 /*
2  Simple DirectMedia Layer
3  Copyright (C) 1997-2014 Sam Lantinga <slouken@libsdl.org>
4 
5  This software is provided 'as-is', without any express or implied
6  warranty. In no event will the authors be held liable for any damages
7  arising from the use of this software.
8 
9  Permission is granted to anyone to use this software for any purpose,
10  including commercial applications, and to alter it and redistribute it
11  freely, subject to the following restrictions:
12 
13  1. The origin of this software must not be misrepresented; you must not
14  claim that you wrote the original software. If you use this software
15  in a product, an acknowledgment in the product documentation would be
16  appreciated but is not required.
17  2. Altered source versions must be plainly marked as such, and must not be
18  misrepresented as being the original software.
19  3. This notice may not be removed or altered from any source distribution.
20 */
21 
59 #ifndef _SDL_atomic_h_
60 #define _SDL_atomic_h_
61 
62 #include "SDL_stdinc.h"
63 #include "SDL_platform.h"
64 
65 #include "begin_code.h"
66 
67 /* Set up for C function definitions, even when using C++ */
68 #ifdef __cplusplus
69 extern "C" {
70 #endif
71 
87 /* @{ */
88 
89 typedef int SDL_SpinLock;
90 
98 extern DECLSPEC SDL_bool SDLCALL SDL_AtomicTryLock(SDL_SpinLock *lock);
99 
105 extern DECLSPEC void SDLCALL SDL_AtomicLock(SDL_SpinLock *lock);
106 
112 extern DECLSPEC void SDLCALL SDL_AtomicUnlock(SDL_SpinLock *lock);
113 
114 /* @} *//* SDL AtomicLock */
115 
116 
121 #if defined(_MSC_VER) && (_MSC_VER > 1200)
122 void _ReadWriteBarrier(void);
123 #pragma intrinsic(_ReadWriteBarrier)
124 #define SDL_CompilerBarrier() _ReadWriteBarrier()
125 #elif defined(__GNUC__)
126 #define SDL_CompilerBarrier() __asm__ __volatile__ ("" : : : "memory")
127 #else
128 #define SDL_CompilerBarrier() \
129 { SDL_SpinLock _tmp = 0; SDL_AtomicLock(&_tmp); SDL_AtomicUnlock(&_tmp); }
130 #endif
131 
151 #if defined(__GNUC__) && (defined(__powerpc__) || defined(__ppc__))
152 #define SDL_MemoryBarrierRelease() __asm__ __volatile__ ("lwsync" : : : "memory")
153 #define SDL_MemoryBarrierAcquire() __asm__ __volatile__ ("lwsync" : : : "memory")
154 #elif defined(__GNUC__) && defined(__arm__)
155 #if defined(__ARM_ARCH_7__) || defined(__ARM_ARCH_7A__) || defined(__ARM_ARCH_7EM__) || defined(__ARM_ARCH_7R__) || defined(__ARM_ARCH_7M__) || defined(__ARM_ARCH_7S__)
156 #define SDL_MemoryBarrierRelease() __asm__ __volatile__ ("dmb ish" : : : "memory")
157 #define SDL_MemoryBarrierAcquire() __asm__ __volatile__ ("dmb ish" : : : "memory")
158 #elif defined(__ARM_ARCH_6__) || defined(__ARM_ARCH_6J__) || defined(__ARM_ARCH_6K__) || defined(__ARM_ARCH_6T2__) || defined(__ARM_ARCH_6Z__) || defined(__ARM_ARCH_6ZK__)
159 #ifdef __thumb__
160 /* The mcr instruction isn't available in thumb mode, use real functions */
161 extern DECLSPEC void SDLCALL SDL_MemoryBarrierRelease();
162 extern DECLSPEC void SDLCALL SDL_MemoryBarrierAcquire();
163 #else
164 #define SDL_MemoryBarrierRelease() __asm__ __volatile__ ("mcr p15, 0, %0, c7, c10, 5" : : "r"(0) : "memory")
165 #define SDL_MemoryBarrierAcquire() __asm__ __volatile__ ("mcr p15, 0, %0, c7, c10, 5" : : "r"(0) : "memory")
166 #endif /* __thumb__ */
167 #else
168 #define SDL_MemoryBarrierRelease() __asm__ __volatile__ ("" : : : "memory")
169 #define SDL_MemoryBarrierAcquire() __asm__ __volatile__ ("" : : : "memory")
170 #endif /* __GNUC__ && __arm__ */
171 #else
172 /* This is correct for the x86 and x64 CPUs, and we'll expand this over time. */
173 #define SDL_MemoryBarrierRelease() SDL_CompilerBarrier()
174 #define SDL_MemoryBarrierAcquire() SDL_CompilerBarrier()
175 #endif
176 
181 typedef struct { int value; } SDL_atomic_t;
182 
190 extern DECLSPEC SDL_bool SDLCALL SDL_AtomicCAS(SDL_atomic_t *a, int oldval, int newval);
191 
197 extern DECLSPEC int SDLCALL SDL_AtomicSet(SDL_atomic_t *a, int v);
198 
202 extern DECLSPEC int SDLCALL SDL_AtomicGet(SDL_atomic_t *a);
203 
211 extern DECLSPEC int SDLCALL SDL_AtomicAdd(SDL_atomic_t *a, int v);
212 
216 #ifndef SDL_AtomicIncRef
217 #define SDL_AtomicIncRef(a) SDL_AtomicAdd(a, 1)
218 #endif
219 
226 #ifndef SDL_AtomicDecRef
227 #define SDL_AtomicDecRef(a) (SDL_AtomicAdd(a, -1) == 1)
228 #endif
229 
237 extern DECLSPEC SDL_bool SDLCALL SDL_AtomicCASPtr(void **a, void *oldval, void *newval);
238 
244 extern DECLSPEC void* SDLCALL SDL_AtomicSetPtr(void **a, void* v);
245 
249 extern DECLSPEC void* SDLCALL SDL_AtomicGetPtr(void **a);
250 
251 /* Ends C function definitions when using C++ */
252 #ifdef __cplusplus
253 }
254 #endif
255 
256 #include "close_code.h"
257 
258 #endif /* _SDL_atomic_h_ */
259 
260 /* vi: set ts=4 sw=4 expandtab: */
DECLSPEC void *SDLCALL SDL_AtomicGetPtr(void **a)
Get the value of a pointer atomically.
DECLSPEC int SDLCALL SDL_AtomicSet(SDL_atomic_t *a, int v)
Set an atomic variable to a value.
DECLSPEC int SDLCALL SDL_AtomicGet(SDL_atomic_t *a)
Get the value of an atomic variable.
DECLSPEC void *SDLCALL SDL_AtomicSetPtr(void **a, void *v)
Set a pointer to a value atomically.
DECLSPEC SDL_bool SDLCALL SDL_AtomicCASPtr(void **a, void *oldval, void *newval)
Set a pointer to a new value if it is currently an old value.
DECLSPEC SDL_bool SDLCALL SDL_AtomicTryLock(SDL_SpinLock *lock)
Try to lock a spin lock by setting it to a non-zero value.
#define SDL_MemoryBarrierRelease()
Definition: SDL_atomic.h:173
DECLSPEC void SDLCALL SDL_AtomicLock(SDL_SpinLock *lock)
Lock a spin lock by setting it to a non-zero value.
DECLSPEC SDL_bool SDLCALL SDL_AtomicCAS(SDL_atomic_t *a, int oldval, int newval)
Set an atomic variable to a new value if it is currently an old value.
DECLSPEC int SDLCALL SDL_AtomicAdd(SDL_atomic_t *a, int v)
Add to an atomic variable.
A type representing an atomic integer value. It is a struct so people don't accidentally use numeric ...
Definition: SDL_atomic.h:181
DECLSPEC void SDLCALL SDL_AtomicUnlock(SDL_SpinLock *lock)
Unlock a spin lock by setting it to 0. Always returns immediately.