xref: /libuv/src/win/atomicops-inl.h (revision f9ad802f)
1 /* Copyright Joyent, Inc. and other Node contributors. All rights reserved.
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3  * Permission is hereby granted, free of charge, to any person obtaining a copy
4  * of this software and associated documentation files (the "Software"), to
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7  * sell copies of the Software, and to permit persons to whom the Software is
8  * furnished to do so, subject to the following conditions:
9  *
10  * The above copyright notice and this permission notice shall be included in
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14  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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19  * IN THE SOFTWARE.
20  */
21 
22 #ifndef UV_WIN_ATOMICOPS_INL_H_
23 #define UV_WIN_ATOMICOPS_INL_H_
24 
25 #include "uv.h"
26 #include "internal.h"
27 
28 
29 /* Atomic set operation on char */
30 #ifdef _MSC_VER /* MSVC */
31 
32 /* _InterlockedOr8 is supported by MSVC on x32 and x64. It is slightly less
33  * efficient than InterlockedExchange, but InterlockedExchange8 does not exist,
34  * and interlocked operations on larger targets might require the target to be
35  * aligned. */
36 #pragma intrinsic(_InterlockedOr8)
37 
uv__atomic_exchange_set(char volatile * target)38 static char INLINE uv__atomic_exchange_set(char volatile* target) {
39   return _InterlockedOr8(target, 1);
40 }
41 
42 #else /* GCC, Clang in mingw mode */
43 
uv__atomic_exchange_set(char volatile * target)44 static inline char uv__atomic_exchange_set(char volatile* target) {
45 #if defined(__i386__) || defined(__x86_64__)
46   /* Mingw-32 version, hopefully this works for 64-bit gcc as well. */
47   const char one = 1;
48   char old_value;
49   __asm__ __volatile__ ("lock xchgb %0, %1\n\t"
50                         : "=r"(old_value), "=m"(*target)
51                         : "0"(one), "m"(*target)
52                         : "memory");
53   return old_value;
54 #else
55   return __sync_fetch_and_or(target, 1);
56 #endif
57 }
58 
59 #endif
60 
61 #endif /* UV_WIN_ATOMICOPS_INL_H_ */
62