src/lock.h

   1 /*
   2   Glaurung, a UCI chess playing engine.
   3   Copyright (C) 2004-2008 Tord Romstad
   4
   5   Glaurung is free software: you can redistribute it and/or modify
   6   it under the terms of the GNU General Public License as published by
   7   the Free Software Foundation, either version 3 of the License, or
   8   (at your option) any later version.
   9
  10   Glaurung is distributed in the hope that it will be useful,
  11   but WITHOUT ANY WARRANTY; without even the implied warranty of
  12   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13   GNU General Public License for more details.
  14
  15   You should have received a copy of the GNU General Public License
  16   along with this program.  If not, see <http://www.gnu.org/licenses/>.
  17 */
  18
  19
  20 #if !defined(LOCK_H_INCLUDED)
  21 #define LOCK_H_INCLUDED
  22
  23
  24 // x86 assembly language locks or OS spin locks may perform faster than
  25 // mutex locks on some platforms.  On my machine, mutexes seem to be the
  26 // best.
  27
  28 //#define ASM_LOCK
  29 //#define OS_SPIN_LOCK
  30
  31
  32 #if defined(ASM_LOCK)
  33
  34
  35 typedef volatile int Lock;
  36
  37 static inline void LockX86(Lock *lock) {
  38   int dummy;
  39   asm __volatile__("1:          movl    $1, %0" "\n\t"
  40       "            xchgl   (%1), %0" "\n\t" "            testl   %0, %0" "\n\t"
  41       "            jz      3f" "\n\t" "2:          pause" "\n\t"
  42       "            movl    (%1), %0" "\n\t" "            testl   %0, %0" "\n\t"
  43       "            jnz     2b" "\n\t" "            jmp     1b" "\n\t" "3:"
  44       "\n\t":"=&q"(dummy)
  45       :"q"(lock)
  46       :"cc");
  47 }
  48
  49 static inline void UnlockX86(Lock *lock) {
  50   int dummy;
  51   asm __volatile__("movl    $0, (%1)":"=&q"(dummy)
  52       :"q"(lock));
  53 }
  54
  55 #  define lock_init(x, y) (*(x) = 0)
  56 #  define lock_grab(x) LockX86(x)
  57 #  define lock_release(x) UnlockX86(x)
  58 #  define lock_destroy(x)
  59
  60
  61 #elif defined(OS_SPIN_LOCK)
  62
  63
  64 #  include <libkern/OSAtomic.h>
  65
  66 typedef OSSpinLock Lock;
  67
  68 #  define lock_init(x, y) (*(x) = 0)
  69 #  define lock_grab(x) OSSpinLockLock(x)
  70 #  define lock_release(x) OSSpinLockUnlock(x)
  71 #  define lock_destroy(x)
  72
  73
  74 #elif !defined(_MSC_VER)
  75
  76 #  include <pthread.h>
  77
  78 typedef pthread_mutex_t Lock;
  79
  80 #  define lock_init(x, y) pthread_mutex_init(x, y)
  81 #  define lock_grab(x) pthread_mutex_lock(x)
  82 #  define lock_release(x) pthread_mutex_unlock(x)
  83 #  define lock_destroy(x) pthread_mutex_destroy(x)
  84
  85
  86 #else
  87
  88
  89 #  include <windows.h>
  90
  91 typedef CRITICAL_SECTION Lock;
  92 #  define lock_init(x, y) InitializeCriticalSection(x)
  93 #  define lock_grab(x) EnterCriticalSection(x)
  94 #  define lock_release(x) LeaveCriticalSection(x)
  95 #  define lock_destroy(x) DeleteCriticalSection(x)
  96
  97
  98 #endif
  99
 100
 101 #endif // !defined(LOCK_H_INCLUDED)