sysdeps/mach/powerpc/machine-lock.h

   1 /* Machine-specific definition for spin locks.  PowerPC version.
   2    Copyright (C) 1994,97,2002,2007 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library 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 GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    02111-1307 USA.  */
  19
  20 #ifndef _MACHINE_LOCK_H
  21 #define _MACHINE_LOCK_H
  22
  23 /* The type of a spin lock variable.  */
  24
  25 typedef __volatile long int __spin_lock_t;
  26
  27 /* Value to initialize `__spin_lock_t' variables to.  */
  28
  29 #define __SPIN_LOCK_INITIALIZER 0L
  30
  31
  32 #ifndef _EXTERN_INLINE
  33 #define _EXTERN_INLINE __extern_inline
  34 #endif
  35
  36 /* Unlock LOCK.  */
  37
  38 _EXTERN_INLINE void
  39 __spin_unlock (__spin_lock_t *__lock)
  40 {
  41   long int __locked;
  42   __asm__ __volatile__ ("\
  43 0:      lwarx   %0,0,%1\n\
  44         stwcx.  %2,0,%1\n\
  45         bne-    0b\n\
  46 " : "=&r" (__locked) : "r" (__lock), "r" (0) : "cr0");
  47 }
  48
  49 /* Try to lock LOCK; return nonzero if we locked it, zero if another has.  */
  50
  51 _EXTERN_INLINE int
  52 __spin_try_lock (register __spin_lock_t *__lock)
  53 {
  54   long int __rtn;
  55   __asm__ __volatile__ ("\
  56 0:      lwarx   %0,0,%1\n\
  57         stwcx.  %2,0,%1\n\
  58         bne-    0b\n\
  59 " : "=&r" (__rtn) : "r" (__lock), "r" (1) : "cr0");
  60   return !__rtn;
  61 }
  62
  63 /* Return nonzero if LOCK is locked.  */
  64
  65 _EXTERN_INLINE int
  66 __spin_lock_locked (__spin_lock_t *__lock)
  67 {
  68   long int __rtn;
  69   __asm__ __volatile__ ("\
  70 0:      lwarx   %0,0,%1\n\
  71         stwcx.  %0,0,%1\n\
  72         bne-    0b\n\
  73 " : "=&r" (__rtn) : "r" (__lock) : "cr0");
  74   return __rtn;
  75 }
  76
  77
  78 #endif /* machine-lock.h */