sysdeps/mach/mips/machine-lock.h

   1 /* Machine-specific definition for spin locks.  MIPS version.
   2    Copyright (C) 1996, 1997 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 /* To get the TAS pseudo-instruction. */
  24 #include <mach/mips/mips_instruction.h>
  25
  26 /* The type of a spin lock variable.  */
  27
  28 typedef __volatile int __spin_lock_t;
  29
  30 /* Value to initialize `__spin_lock_t' variables to.  */
  31
  32 #define __SPIN_LOCK_INITIALIZER 0
  33
  34
  35 #ifndef _EXTERN_INLINE
  36 #define _EXTERN_INLINE extern __inline
  37 #endif
  38
  39 /* Unlock LOCK.  */
  40
  41 _EXTERN_INLINE void
  42 __spin_unlock (__spin_lock_t *__lock)
  43 {
  44   *__lock = 0;
  45 }
  46
  47 /* Try to lock LOCK; return nonzero if we locked it, zero if another has.  */
  48
  49 _EXTERN_INLINE int
  50 __spin_try_lock (register __spin_lock_t *__lock)
  51 {
  52 #if (__mips >= 2)
  53   int __rtn;
  54
  55   __asm__ __volatile (".set noreorder");
  56 #if (__mips64)
  57   __asm__ __volatile ("lld %0,0(%1)" : "=r" (__rtn) : "r" (__lock));
  58 #else
  59   __asm__ __volatile ("ll %0,0(%1)" : "=r" (__rtn) : "r" (__lock));
  60 #endif
  61   if (__rtn)
  62     return 0;
  63   __asm__ __volatile ("move %0,%1" : "=r" (__rtn) : "r" (__lock));
  64 #if (__mips64)
  65   __asm__ __volatile ("scd %0,0(%1)" : "=r" (__rtn) : "r" (__lock));
  66 #else
  67   __asm__ __volatile ("sc %0,0(%1)" : "=r" (__rtn) : "r" (__lock));
  68 #endif
  69   __asm__ __volatile (".set reorder");
  70   return __rtn;
  71 #else
  72   register int __rtn __asm__ ("a0");
  73
  74   /* Use the Mach microkernel's emulated TAS pseudo-instruction.  */
  75   __asm__ __volatile (".set noreorder");
  76   __asm__ __volatile (".word %1" : "=r" (__rtn) : "i" (op_tas), "0" (__lock));
  77   __asm__ __volatile ("nop");
  78   __asm__ __volatile (".set reorder");
  79   return __rtn ^ (int) __lock;
  80 #endif
  81 }
  82
  83 /* Return nonzero if LOCK is locked.  */
  84
  85 _EXTERN_INLINE int
  86 __spin_lock_locked (__spin_lock_t *__lock)
  87 {
  88   return *__lock != 0;
  89 }
  90
  91
  92 #endif /* machine-lock.h */