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lock.h
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lock.h
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/*
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
Copyright (C) 2008-2010 Marco Costalba, Joona Kiiski, Tord Romstad
Stockfish is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
Stockfish is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#if !defined(LOCK_H_INCLUDED)
#define LOCK_H_INCLUDED
// x86 assembly language locks or OS spin locks may perform faster than
// mutex locks on some platforms. On my machine, mutexes seem to be the
// best.
//#define ASM_LOCK
//#define OS_SPIN_LOCK
#if defined(ASM_LOCK)
typedef volatile int Lock;
static inline void LockX86(Lock *lock) {
int dummy;
asm __volatile__("1: movl $1, %0" "\n\t"
" xchgl (%1), %0" "\n\t" " testl %0, %0" "\n\t"
" jz 3f" "\n\t" "2: pause" "\n\t"
" movl (%1), %0" "\n\t" " testl %0, %0" "\n\t"
" jnz 2b" "\n\t" " jmp 1b" "\n\t" "3:"
"\n\t":"=&q"(dummy)
:"q"(lock)
:"cc");
}
static inline void UnlockX86(Lock *lock) {
int dummy;
asm __volatile__("movl $0, (%1)":"=&q"(dummy)
:"q"(lock));
}
# define lock_init(x, y) (*(x) = 0)
# define lock_grab(x) LockX86(x)
# define lock_release(x) UnlockX86(x)
# define lock_destroy(x)
#elif defined(OS_SPIN_LOCK)
# include <libkern/OSAtomic.h>
typedef OSSpinLock Lock;
# define lock_init(x, y) (*(x) = 0)
# define lock_grab(x) OSSpinLockLock(x)
# define lock_release(x) OSSpinLockUnlock(x)
# define lock_destroy(x)
#elif !defined(_MSC_VER)
# include <pthread.h>
typedef pthread_mutex_t Lock;
# define lock_init(x, y) pthread_mutex_init(x, y)
# define lock_grab(x) pthread_mutex_lock(x)
# define lock_release(x) pthread_mutex_unlock(x)
# define lock_destroy(x) pthread_mutex_destroy(x)
#else
#define WIN32_LEAN_AND_MEAN
#include <windows.h>
#undef WIN32_LEAN_AND_MEAN
typedef CRITICAL_SECTION Lock;
# define lock_init(x, y) InitializeCriticalSection(x)
# define lock_grab(x) EnterCriticalSection(x)
# define lock_release(x) LeaveCriticalSection(x)
# define lock_destroy(x) DeleteCriticalSection(x)
#endif
#endif // !defined(LOCK_H_INCLUDED)