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SDL_atomic.h
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1/*
2 Simple DirectMedia Layer
3 Copyright (C) 1997-2023 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
69extern "C" {
70#endif
71
87/* @{ */
88
89typedef int SDL_SpinLock;
90
106extern DECLSPEC SDL_bool SDLCALL SDL_AtomicTryLock(SDL_SpinLock *lock);
107
121extern DECLSPEC void SDLCALL SDL_AtomicLock(SDL_SpinLock *lock);
122
138extern DECLSPEC void SDLCALL SDL_AtomicUnlock(SDL_SpinLock *lock);
139
140/* @} *//* SDL AtomicLock */
141
142
147#if defined(_MSC_VER) && (_MSC_VER > 1200) && !defined(__clang__)
148void _ReadWriteBarrier(void);
149#pragma intrinsic(_ReadWriteBarrier)
150#define SDL_CompilerBarrier() _ReadWriteBarrier()
151#elif (defined(__GNUC__) && !defined(__EMSCRIPTEN__)) || (defined(__SUNPRO_C) && (__SUNPRO_C >= 0x5120))
152/* This is correct for all CPUs when using GCC or Solaris Studio 12.1+. */
153#define SDL_CompilerBarrier() __asm__ __volatile__ ("" : : : "memory")
154#elif defined(__WATCOMC__)
155extern __inline void SDL_CompilerBarrier(void);
156#pragma aux SDL_CompilerBarrier = "" parm [] modify exact [];
157#else
158#define SDL_CompilerBarrier() \
159{ SDL_SpinLock _tmp = 0; SDL_AtomicLock(&_tmp); SDL_AtomicUnlock(&_tmp); }
160#endif
161
183extern DECLSPEC void SDLCALL SDL_MemoryBarrierReleaseFunction(void);
184extern DECLSPEC void SDLCALL SDL_MemoryBarrierAcquireFunction(void);
185
186#if defined(__GNUC__) && (defined(__powerpc__) || defined(__ppc__))
187#define SDL_MemoryBarrierRelease() __asm__ __volatile__ ("lwsync" : : : "memory")
188#define SDL_MemoryBarrierAcquire() __asm__ __volatile__ ("lwsync" : : : "memory")
189#elif defined(__GNUC__) && defined(__aarch64__)
190#define SDL_MemoryBarrierRelease() __asm__ __volatile__ ("dmb ish" : : : "memory")
191#define SDL_MemoryBarrierAcquire() __asm__ __volatile__ ("dmb ish" : : : "memory")
192#elif defined(__GNUC__) && defined(__arm__)
193#if 0 /* defined(__LINUX__) || defined(__ANDROID__) */
194/* Information from:
195 https://chromium.googlesource.com/chromium/chromium/+/trunk/base/atomicops_internals_arm_gcc.h#19
196
197 The Linux kernel provides a helper function which provides the right code for a memory barrier,
198 hard-coded at address 0xffff0fa0
199*/
200typedef void (*SDL_KernelMemoryBarrierFunc)();
201#define SDL_MemoryBarrierRelease() ((SDL_KernelMemoryBarrierFunc)0xffff0fa0)()
202#define SDL_MemoryBarrierAcquire() ((SDL_KernelMemoryBarrierFunc)0xffff0fa0)()
203#elif 0 /* defined(__QNXNTO__) */
204#include <sys/cpuinline.h>
205
206#define SDL_MemoryBarrierRelease() __cpu_membarrier()
207#define SDL_MemoryBarrierAcquire() __cpu_membarrier()
208#else
209#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__) || defined(__ARM_ARCH_8A__)
210#define SDL_MemoryBarrierRelease() __asm__ __volatile__ ("dmb ish" : : : "memory")
211#define SDL_MemoryBarrierAcquire() __asm__ __volatile__ ("dmb ish" : : : "memory")
212#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__) || defined(__ARM_ARCH_5TE__)
213#ifdef __thumb__
214/* The mcr instruction isn't available in thumb mode, use real functions */
215#define SDL_MEMORY_BARRIER_USES_FUNCTION
216#define SDL_MemoryBarrierRelease() SDL_MemoryBarrierReleaseFunction()
217#define SDL_MemoryBarrierAcquire() SDL_MemoryBarrierAcquireFunction()
218#else
219#define SDL_MemoryBarrierRelease() __asm__ __volatile__ ("mcr p15, 0, %0, c7, c10, 5" : : "r"(0) : "memory")
220#define SDL_MemoryBarrierAcquire() __asm__ __volatile__ ("mcr p15, 0, %0, c7, c10, 5" : : "r"(0) : "memory")
221#endif /* __thumb__ */
222#else
223#define SDL_MemoryBarrierRelease() __asm__ __volatile__ ("" : : : "memory")
224#define SDL_MemoryBarrierAcquire() __asm__ __volatile__ ("" : : : "memory")
225#endif /* __LINUX__ || __ANDROID__ */
226#endif /* __GNUC__ && __arm__ */
227#else
228#if (defined(__SUNPRO_C) && (__SUNPRO_C >= 0x5120))
229/* This is correct for all CPUs on Solaris when using Solaris Studio 12.1+. */
230#include <mbarrier.h>
231#define SDL_MemoryBarrierRelease() __machine_rel_barrier()
232#define SDL_MemoryBarrierAcquire() __machine_acq_barrier()
233#else
234/* This is correct for the x86 and x64 CPUs, and we'll expand this over time. */
235#define SDL_MemoryBarrierRelease() SDL_CompilerBarrier()
236#define SDL_MemoryBarrierAcquire() SDL_CompilerBarrier()
237#endif
238#endif
239
240/* "REP NOP" is PAUSE, coded for tools that don't know it by that name. */
241#if (defined(__GNUC__) || defined(__clang__)) && (defined(__i386__) || defined(__x86_64__))
242 #define SDL_CPUPauseInstruction() __asm__ __volatile__("pause\n") /* Some assemblers can't do REP NOP, so go with PAUSE. */
243#elif (defined(__arm__) && __ARM_ARCH >= 7) || defined(__aarch64__)
244 #define SDL_CPUPauseInstruction() __asm__ __volatile__("yield" ::: "memory")
245#elif (defined(__powerpc__) || defined(__powerpc64__))
246 #define SDL_CPUPauseInstruction() __asm__ __volatile__("or 27,27,27");
247#elif defined(_MSC_VER) && (defined(_M_IX86) || defined(_M_X64))
248 #define SDL_CPUPauseInstruction() _mm_pause() /* this is actually "rep nop" and not a SIMD instruction. No inline asm in MSVC x86-64! */
249#elif defined(_MSC_VER) && (defined(_M_ARM) || defined(_M_ARM64))
250 #define SDL_CPUPauseInstruction() __yield()
251#elif defined(__WATCOMC__) && defined(__386__)
252 /* watcom assembler rejects PAUSE if CPU < i686, and it refuses REP NOP as an invalid combination. Hardcode the bytes. */
253 extern __inline void SDL_CPUPauseInstruction(void);
254 #pragma aux SDL_CPUPauseInstruction = "db 0f3h,90h"
255#else
256 #define SDL_CPUPauseInstruction()
257#endif
258
259
264typedef struct { int value; } SDL_atomic_t;
265
283extern DECLSPEC SDL_bool SDLCALL SDL_AtomicCAS(SDL_atomic_t *a, int oldval, int newval);
284
301extern DECLSPEC int SDLCALL SDL_AtomicSet(SDL_atomic_t *a, int v);
302
316extern DECLSPEC int SDLCALL SDL_AtomicGet(SDL_atomic_t *a);
317
335extern DECLSPEC int SDLCALL SDL_AtomicAdd(SDL_atomic_t *a, int v);
336
340#ifndef SDL_AtomicIncRef
341#define SDL_AtomicIncRef(a) SDL_AtomicAdd(a, 1)
342#endif
343
350#ifndef SDL_AtomicDecRef
351#define SDL_AtomicDecRef(a) (SDL_AtomicAdd(a, -1) == 1)
352#endif
353
371extern DECLSPEC SDL_bool SDLCALL SDL_AtomicCASPtr(void **a, void *oldval, void *newval);
372
388extern DECLSPEC void* SDLCALL SDL_AtomicSetPtr(void **a, void* v);
389
404extern DECLSPEC void* SDLCALL SDL_AtomicGetPtr(void **a);
405
406/* Ends C function definitions when using C++ */
407#ifdef __cplusplus
408}
409#endif
410
411#include "close_code.h"
412
413#endif /* SDL_atomic_h_ */
414
415/* vi: set ts=4 sw=4 expandtab: */
DECLSPEC void *SDLCALL SDL_AtomicSetPtr(void **a, void *v)
DECLSPEC int SDLCALL SDL_AtomicAdd(SDL_atomic_t *a, int v)
#define SDL_CompilerBarrier()
Definition: SDL_atomic.h:158
DECLSPEC void SDLCALL SDL_AtomicUnlock(SDL_SpinLock *lock)
DECLSPEC void SDLCALL SDL_MemoryBarrierReleaseFunction(void)
DECLSPEC SDL_bool SDLCALL SDL_AtomicTryLock(SDL_SpinLock *lock)
DECLSPEC int SDLCALL SDL_AtomicGet(SDL_atomic_t *a)
DECLSPEC int SDLCALL SDL_AtomicSet(SDL_atomic_t *a, int v)
DECLSPEC void SDLCALL SDL_AtomicLock(SDL_SpinLock *lock)
DECLSPEC SDL_bool SDLCALL SDL_AtomicCASPtr(void **a, void *oldval, void *newval)
DECLSPEC void *SDLCALL SDL_AtomicGetPtr(void **a)
DECLSPEC SDL_bool SDLCALL SDL_AtomicCAS(SDL_atomic_t *a, int oldval, int newval)
A type representing an atomic integer value. It is a struct so people don't accidentally use numeric ...
Definition: SDL_atomic.h:264