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SDL_atomic.h
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1 /*
2  Simple DirectMedia Layer
3  Copyright (C) 1997-2016 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__) && !defined(__EMSCRIPTEN__)) || (defined(__SUNPRO_C) && (__SUNPRO_C >= 0x5120))
126 /* This is correct for all CPUs when using GCC or Solaris Studio 12.1+. */
127 #define SDL_CompilerBarrier() __asm__ __volatile__ ("" : : : "memory")
128 #else
129 #define SDL_CompilerBarrier() \
130 { SDL_SpinLock _tmp = 0; SDL_AtomicLock(&_tmp); SDL_AtomicUnlock(&_tmp); }
131 #endif
132 
152 #if defined(__GNUC__) && (defined(__powerpc__) || defined(__ppc__))
153 #define SDL_MemoryBarrierRelease() __asm__ __volatile__ ("lwsync" : : : "memory")
154 #define SDL_MemoryBarrierAcquire() __asm__ __volatile__ ("lwsync" : : : "memory")
155 #elif defined(__GNUC__) && defined(__arm__)
156 #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__)
157 #define SDL_MemoryBarrierRelease() __asm__ __volatile__ ("dmb ish" : : : "memory")
158 #define SDL_MemoryBarrierAcquire() __asm__ __volatile__ ("dmb ish" : : : "memory")
159 #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__)
160 #ifdef __thumb__
161 /* The mcr instruction isn't available in thumb mode, use real functions */
162 extern DECLSPEC void SDLCALL SDL_MemoryBarrierRelease();
163 extern DECLSPEC void SDLCALL SDL_MemoryBarrierAcquire();
164 #else
165 #define SDL_MemoryBarrierRelease() __asm__ __volatile__ ("mcr p15, 0, %0, c7, c10, 5" : : "r"(0) : "memory")
166 #define SDL_MemoryBarrierAcquire() __asm__ __volatile__ ("mcr p15, 0, %0, c7, c10, 5" : : "r"(0) : "memory")
167 #endif /* __thumb__ */
168 #else
169 #define SDL_MemoryBarrierRelease() __asm__ __volatile__ ("" : : : "memory")
170 #define SDL_MemoryBarrierAcquire() __asm__ __volatile__ ("" : : : "memory")
171 #endif /* __GNUC__ && __arm__ */
172 #else
173 #if (defined(__SUNPRO_C) && (__SUNPRO_C >= 0x5120))
174 /* This is correct for all CPUs on Solaris when using Solaris Studio 12.1+. */
175 #include <mbarrier.h>
176 #define SDL_MemoryBarrierRelease() __machine_rel_barrier()
177 #define SDL_MemoryBarrierAcquire() __machine_acq_barrier()
178 #else
179 /* This is correct for the x86 and x64 CPUs, and we'll expand this over time. */
180 #define SDL_MemoryBarrierRelease() SDL_CompilerBarrier()
181 #define SDL_MemoryBarrierAcquire() SDL_CompilerBarrier()
182 #endif
183 #endif
184 
189 typedef struct { int value; } SDL_atomic_t;
190 
198 extern DECLSPEC SDL_bool SDLCALL SDL_AtomicCAS(SDL_atomic_t *a, int oldval, int newval);
199 
205 extern DECLSPEC int SDLCALL SDL_AtomicSet(SDL_atomic_t *a, int v);
206 
210 extern DECLSPEC int SDLCALL SDL_AtomicGet(SDL_atomic_t *a);
211 
219 extern DECLSPEC int SDLCALL SDL_AtomicAdd(SDL_atomic_t *a, int v);
220 
224 #ifndef SDL_AtomicIncRef
225 #define SDL_AtomicIncRef(a) SDL_AtomicAdd(a, 1)
226 #endif
227 
234 #ifndef SDL_AtomicDecRef
235 #define SDL_AtomicDecRef(a) (SDL_AtomicAdd(a, -1) == 1)
236 #endif
237 
245 extern DECLSPEC SDL_bool SDLCALL SDL_AtomicCASPtr(void **a, void *oldval, void *newval);
246 
252 extern DECLSPEC void* SDLCALL SDL_AtomicSetPtr(void **a, void* v);
253 
257 extern DECLSPEC void* SDLCALL SDL_AtomicGetPtr(void **a);
258 
259 /* Ends C function definitions when using C++ */
260 #ifdef __cplusplus
261 }
262 #endif
263 
264 #include "close_code.h"
265 
266 #endif /* _SDL_atomic_h_ */
267 
268 /* 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:180
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&#39;t accidentally use numeric ...
Definition: SDL_atomic.h:189
DECLSPEC void SDLCALL SDL_AtomicUnlock(SDL_SpinLock *lock)
Unlock a spin lock by setting it to 0. Always returns immediately.