SameBoy/Windows/pthread.h

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2.3 KiB
C
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/* Very minimal pthread implementation for Windows */
#include <Windows.h>
#include <assert.h>
typedef HANDLE pthread_t;
typedef struct pthread_attr_s pthread_attr_t;
static inline int pthread_create(pthread_t *pthread,
const pthread_attr_t *attrs,
LPTHREAD_START_ROUTINE function,
void *context)
{
assert(!attrs);
*pthread = CreateThread(NULL, 0, function,
context, 0, NULL);
return *pthread? 0 : GetLastError();
}
typedef struct {
unsigned status;
CRITICAL_SECTION cs;
} pthread_mutex_t;
#define PTHREAD_MUTEX_INITIALIZER {0,}
static inline CRITICAL_SECTION *pthread_mutex_to_cs(pthread_mutex_t *mutex)
{
retry:
if (mutex->status == 2) return &mutex->cs;
unsigned expected = 0;
unsigned desired = 1;
if (__atomic_compare_exchange(&mutex->status, &expected, &desired, false, __ATOMIC_RELAXED, __ATOMIC_RELAXED)) {
InitializeCriticalSection(&mutex->cs);
mutex->status = 2;
return &mutex->cs;
}
goto retry;
}
static inline int pthread_mutex_lock(pthread_mutex_t *mutex)
{
EnterCriticalSection(pthread_mutex_to_cs(mutex));
return 0;
}
static inline int pthread_mutex_unlock(pthread_mutex_t *mutex)
{
LeaveCriticalSection(pthread_mutex_to_cs(mutex));
return 0;
}
typedef struct {
unsigned status;
CONDITION_VARIABLE cond;
} pthread_cond_t;
#define PTHREAD_COND_INITIALIZER {0,}
static inline CONDITION_VARIABLE *pthread_cond_to_win(pthread_cond_t *cond)
{
retry:
if (cond->status == 2) return &cond->cond;
unsigned expected = 0;
unsigned desired = 1;
if (__atomic_compare_exchange(&cond->status, &expected, &desired, false, __ATOMIC_RELAXED, __ATOMIC_RELAXED)) {
InitializeConditionVariable(&cond->cond);
cond->status = 2;
return &cond->cond;
}
goto retry;
}
static inline int pthread_cond_signal(pthread_cond_t *cond)
{
WakeConditionVariable(pthread_cond_to_win(cond));
return 0;
}
static inline int pthread_cond_wait(pthread_cond_t *cond,
pthread_mutex_t *mutex)
{
// Mutex is locked therefore already initialized
return SleepConditionVariableCS(pthread_cond_to_win(cond), &mutex->cs, INFINITE);
}