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c++: move atomic in from cpp-cheat

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TODO: README improve, link to x86 LOCK docs
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Ciro Santilli 六四事件 法轮功
2019-06-26 00:00:00 +00:00
parent e30f53e8a4
commit 88a1c914c9
3 changed files with 29 additions and 5 deletions
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31
userland/cpp/atomic.cpp
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@@ -16,12 +16,31 @@
#if __cplusplus >= 201103L
std::atomic_ulong my_atomic_ulong(0);
unsigned long my_non_atomic_ulong = 0;
#if defined(__x86_64__)
unsigned long my_arch_atomic_ulong = 0;
unsigned long my_arch_non_atomic_ulong = 0;
#endif
size_t niters;
void threadMain() {
for (size_t i = 0; i < niters; ++i) {
my_atomic_ulong++;
my_non_atomic_ulong++;
#if defined(__x86_64__)
__asm__ __volatile__ (
"incq %0;"
: "+m" (my_arch_non_atomic_ulong)
:
:
);
__asm__ __volatile__ (
"lock;"
"incq %0;"
: "+m" (my_arch_atomic_ulong)
:
:
);
#endif
}
}
#endif
@@ -37,7 +56,7 @@ int main(int argc, char **argv) {
if (argc > 2) {
niters = std::stoull(argv[2], NULL, 0);
} else {
niters = 1000;
niters = 10000;
}
std::vector<std::thread> threads(nthreads);
for (size_t i = 0; i < nthreads; ++i)
@@ -45,8 +64,12 @@ int main(int argc, char **argv) {
for (size_t i = 0; i < nthreads; ++i)
threads[i].join();
assert(my_atomic_ulong.load() == nthreads * niters);
// Same as above through `operator T`.
assert(my_atomic_ulong == nthreads * niters);
std::cout << my_non_atomic_ulong << std::endl;
// We can also use the atomics direclty through `operator T` conversion.
assert(my_atomic_ulong == my_atomic_ulong.load());
std::cout << "my_non_atomic_ulong " << my_non_atomic_ulong << std::endl;
#if defined(__x86_64__)
assert(my_arch_atomic_ulong == nthreads * niters);
std::cout << "my_arch_non_atomic_ulong " << my_arch_non_atomic_ulong << std::endl;
#endif
#endif
}