williamr@2: /*
williamr@2:  *
williamr@2:  *
williamr@2:  * Copyright (c) 1994
williamr@2:  * Hewlett-Packard Company
williamr@2:  *
williamr@2:  * Copyright (c) 1996,1997
williamr@2:  * Silicon Graphics Computer Systems, Inc.
williamr@2:  *
williamr@2:  * Copyright (c) 1997
williamr@2:  * Moscow Center for SPARC Technology
williamr@2:  *
williamr@2:  * Copyright (c) 1999 
williamr@2:  * Boris Fomitchev
williamr@2:  *
williamr@2:  * This material is provided "as is", with absolutely no warranty expressed
williamr@2:  * or implied. Any use is at your own risk.
williamr@2:  *
williamr@2:  * Permission to use or copy this software for any purpose is hereby granted 
williamr@2:  * without fee, provided the above notices are retained on all copies.
williamr@2:  * Permission to modify the code and to distribute modified code is granted,
williamr@2:  * provided the above notices are retained, and a notice that the code was
williamr@2:  * modified is included with the above copyright notice.
williamr@2:  *
williamr@2:  */
williamr@2: #ifndef _STLP_THREADS_C
williamr@2: #define _STLP_THREADS_C
williamr@2: 
williamr@2: #ifndef _STLP_INTERNAL_THREADS_H
williamr@2: # include <stl/_threads.h>
williamr@2: #endif
williamr@2: 
williamr@2: # if defined (_STLP_EXPOSE_GLOBALS_IMPLEMENTATION)
williamr@2: 
williamr@2: # if defined(_STLP_SGI_THREADS)
williamr@2: #  include <time.h>
williamr@2: # elif defined (_STLP_UNIX)
williamr@2: #  include <ctime>
williamr@2: # if defined (_STLP_USE_NAMESPACES) && ! defined (_STLP_VENDOR_GLOBAL_CSTD)
williamr@2: using _STLP_VENDOR_CSTD::time_t;
williamr@2: # endif
williamr@2: #  include <sys/time.h>
williamr@2: # endif
williamr@2: 
williamr@2: _STLP_BEGIN_NAMESPACE
williamr@2: 
williamr@2: # if (_STLP_STATIC_TEMPLATE_DATA > 0)
williamr@2: 
williamr@2: #  ifdef _STLP_THREADS
williamr@2: #  if !defined(_STLP_ATOMIC_EXCHANGE) && (defined(_STLP_PTHREADS) || defined(_STLP_UITHREADS) || defined(_STLP_OS2THREADS) || defined(_STLP_USE_PTHREAD_SPINLOCK))
williamr@2: template<int __dummy>
williamr@2: _STLP_STATIC_MUTEX
williamr@2: _Swap_lock_struct<__dummy>::_S_swap_lock _STLP_MUTEX_INITIALIZER;
williamr@2: #  endif
williamr@2: #  endif //_STLP_THREADS
williamr@2: 
williamr@2: #  ifndef _STLP_USE_PTHREAD_SPINLOCK
williamr@2: template <int __inst>
williamr@2: unsigned _STLP_mutex_spin<__inst>::__max = _STLP_mutex_spin<__inst>::__low_max;
williamr@2: 
williamr@2: template <int __inst>
williamr@2: unsigned _STLP_mutex_spin<__inst>::__last = 0;
williamr@2: #  endif // _STLP_USE_PTHREAD_SPINLOCK
williamr@2: 
williamr@2: # else /* ( _STLP_STATIC_TEMPLATE_DATA > 0 ) */
williamr@2: 
williamr@2: #  if defined(_STLP_PTHREADS) || defined(_STLP_UITHREADS) || defined(_STLP_OS2THREADS)
williamr@2: __DECLARE_INSTANCE(_STLP_STATIC_MUTEX, _Swap_lock_struct<0>::_S_swap_lock, 
williamr@2:                    _STLP_MUTEX_INITIALIZER  );
williamr@2: #  endif /* _STLP_PTHREADS */
williamr@2: 
williamr@2: #  ifndef _STLP_USE_PTHREAD_SPINLOCK
williamr@2: __DECLARE_INSTANCE(unsigned, _STLP_mutex_spin<0>::__max,  =30);
williamr@2: __DECLARE_INSTANCE(unsigned, _STLP_mutex_spin<0>::__last, =0);
williamr@2: #  endif // _STLP_USE_PTHREAD_SPINLOCK
williamr@2: 
williamr@2: # endif /* ( _STLP_STATIC_TEMPLATE_DATA > 0 ) */
williamr@2: 
williamr@2: #ifndef _STLP_USE_PTHREAD_SPINLOCK
williamr@2: 
williamr@2: #ifdef _STLP_SPARC_SOLARIS_THREADS
williamr@2: // underground function in libc.so; we do not want dependance on librt
williamr@2: extern "C" int __nanosleep(const struct timespec*, struct timespec*);
williamr@2: # define _STLP_NANOSLEEP __nanosleep
williamr@2: #else
williamr@2: # define _STLP_NANOSLEEP nanosleep
williamr@2: #endif
williamr@2: 
williamr@2: template <int __inst>
williamr@2: void _STLP_CALL
williamr@2: _STLP_mutex_spin<__inst>::_S_nsec_sleep(int __log_nsec) {
williamr@2: #     if defined(_STLP_WIN32THREADS)
williamr@2: 	  if (__log_nsec <= 20) {
williamr@2:         // Note from boost (www.boost.org): 
williamr@2:         // Changed to Sleep(1) from Sleep(0).
williamr@2:         // According to MSDN, Sleep(0) will never yield
williamr@2:         // to a lower-priority thread, whereas Sleep(1)
williamr@2:         // will. Performance seems not to be affected.
williamr@2: 	      Sleep(1);
williamr@2: 	  } else {
williamr@2: 	      Sleep(1 << (__log_nsec - 20));
williamr@2: 	  }
williamr@2: #    elif defined(_STLP_OS2THREADS)
williamr@2:       if (__log_nsec <= 20) {
williamr@2:          DosSleep(0);
williamr@2:       } else {
williamr@2:          DosSleep(1 << (__log_nsec - 20));
williamr@2:       }
williamr@2: #     elif defined (_STLP_UNIX)
williamr@2:           timespec __ts;
williamr@2:           /* Max sleep is 2**27nsec ~ 60msec      */
williamr@2:           __ts.tv_sec = 0;
williamr@2:           __ts.tv_nsec = 1 << __log_nsec;
williamr@2:           _STLP_NANOSLEEP(&__ts, 0);
williamr@2: #     endif
williamr@2:   }
williamr@2: 
williamr@2: 
williamr@2: template <int __inst>
williamr@2: void  _STLP_CALL
williamr@2: _STLP_mutex_spin<__inst>::_M_do_lock(volatile __stl_atomic_t* __lock)
williamr@2: {
williamr@2: #if defined(_STLP_ATOMIC_EXCHANGE)
williamr@2:   if (_Atomic_swap(__lock, 1)) {
williamr@2:     unsigned __my_spin_max = _STLP_mutex_spin<0>::__max;
williamr@2:     unsigned __my_last_spins = _STLP_mutex_spin<0>::__last;
williamr@2:     volatile unsigned __junk = 17; 	// Value doesn't matter.
williamr@2:     unsigned  __i;
williamr@2:     
williamr@2:     for (__i = 0; __i < __my_spin_max; ++__i) {
williamr@2:       if (__i < __my_last_spins/2 || *__lock) {
williamr@2:         __junk *= __junk; __junk *= __junk;
williamr@2:         __junk *= __junk; __junk *= __junk;
williamr@2:       } else {
williamr@2:         if (!_Atomic_swap(__lock, 1)) {
williamr@2:           // got it!
williamr@2:           // Spinning worked.  Thus we're probably not being scheduled
williamr@2:           // against the other process with which we were contending.
williamr@2:           // Thus it makes sense to spin longer the next time.
williamr@2:           _STLP_mutex_spin<0>::__last = __i;
williamr@2:           _STLP_mutex_spin<0>::__max = _STLP_mutex_spin<0>::__high_max;
williamr@2: 	    return;
williamr@2:         }
williamr@2:       }
williamr@2:     }
williamr@2:     
williamr@2:     // We are probably being scheduled against the other process.  Sleep.
williamr@2:     _STLP_mutex_spin<0>::__max = _STLP_mutex_spin<0>::__low_max;
williamr@2:     
williamr@2:     for (__i = 0 ;; ++__i) {
williamr@2:       int __log_nsec = __i + 6;
williamr@2:       
williamr@2:       if (__log_nsec > 27) __log_nsec = 27;
williamr@2:       if (!_Atomic_swap(__lock, 1)) {
williamr@2: 	  break;
williamr@2:       }
williamr@2:       _S_nsec_sleep(__log_nsec);
williamr@2:     }
williamr@2:     
williamr@2:   } /* first _Atomic_swap */
williamr@2: # endif
williamr@2: }
williamr@2: #endif // _STLP_USE_PTHREAD_SPINLOCK
williamr@2: 
williamr@2: _STLP_END_NAMESPACE
williamr@2: 
williamr@2: # endif /* BUILDING_STLPORT */
williamr@2: #endif /*  _STLP_THREADS_C */
williamr@2: 
williamr@2: // Local Variables:
williamr@2: // mode:C++
williamr@2: // End: