libjava/sysdep/sh/locks.h

   1 // locks.h - Thread synchronization primitives. SuperH implementation.
   2
   3 /* Copyright (C) 2002, 2007  Free Software Foundation
   4
   5    This file is part of libgcj.
   6
   7 This software is copyrighted work licensed under the terms of the
   8 Libgcj License.  Please consult the file "LIBGCJ_LICENSE" for
   9 details.  */
  10
  11 #ifndef __SYSDEP_LOCKS_H__
  12 #define __SYSDEP_LOCKS_H__
  13
  14 typedef size_t obj_addr_t;      /* Integer type big enough for object   */
  15                                 /* address.                             */
  16
  17 static unsigned char __cas_lock = 0;
  18
  19 inline static void
  20 __cas_start_atomic (void)
  21 {
  22   unsigned int val;
  23
  24   do
  25     __asm__ __volatile__ ("tas.b @%1; movt %0"
  26                           : "=r" (val)
  27                           : "r" (&__cas_lock)
  28                           : "memory");
  29   while (val == 0);
  30 }
  31
  32 inline static void
  33 __cas_end_atomic (void)
  34 {
  35   __asm__ __volatile__ (" " : : : "memory");
  36   __cas_lock = 0;
  37 }
  38
  39 inline static bool
  40 compare_and_swap (volatile obj_addr_t *addr, obj_addr_t old,
  41                   obj_addr_t new_val)
  42 {
  43   bool ret;
  44
  45   __cas_start_atomic ();
  46   if (*addr != old)
  47     ret = false;
  48   else
  49     {
  50       *addr = new_val;
  51       ret = true;
  52     }
  53   __cas_end_atomic ();
  54
  55   return ret;
  56 }
  57
  58 inline static void
  59 release_set (volatile obj_addr_t *addr, obj_addr_t new_val)
  60 {
  61   __asm__ __volatile__ (" " : : : "memory");
  62   *(addr) = new_val;
  63 }
  64
  65 inline static bool
  66 compare_and_swap_release (volatile obj_addr_t *addr, obj_addr_t old,
  67                           obj_addr_t new_val)
  68 {
  69   return compare_and_swap (addr, old, new_val);
  70 }
  71
  72 inline static void
  73 read_barrier()
  74 {
  75   __asm__ __volatile__(" " : : : "memory");
  76 }
  77
  78 inline static void
  79 write_barrier()
  80 {
  81   __asm__ __volatile__(" " : : : "memory");
  82 }
  83
  84 #endif /* ! __SYSDEP_LOCKS_H__ */