rpcs3/Utilities/sema.cpp
Nekotekina e055d16b2c Replace verify() with ensure() with auto src location.
Expression ensure(x) returns x.
Using comma operator removed.
2020-12-09 15:43:38 +03:00

78 lines
1.1 KiB
C++

#include "sema.h"
void semaphore_base::imp_wait()
{
for (int i = 0; i < 10; i++)
{
busy_wait();
const s32 value = m_value.load();
if (value > 0 && m_value.compare_and_swap_test(value, value - 1))
{
return;
}
}
while (true)
{
// Try hard way
const s32 value = m_value.atomic_op([](s32& value)
{
// Use sign bit to acknowledge waiter presence
if (value && value > INT32_MIN)
{
value--;
if (value < 0)
{
// Remove sign bit
value -= INT32_MIN;
}
}
else
{
// Set sign bit
value = INT32_MIN;
}
return value;
});
if (value >= 0)
{
// Signal other waiter to wake up or to restore sign bit
m_value.notify_one();
return;
}
m_value.wait(value);
}
}
void semaphore_base::imp_post(s32 _old)
{
ensure(_old < 0); // "semaphore_base: overflow"
m_value.notify_one();
}
bool semaphore_base::try_post(s32 _max)
{
// Conditional increment
const s32 value = m_value.fetch_op([&](s32& value)
{
if (value < _max)
{
value += 1;
}
});
if (value < 0)
{
imp_post(value);
}
return value < _max;
}