osfmk/mach/i386/flipc_dep.h

   1 /*
   2  * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
   7  *
   8  * This file contains Original Code and/or Modifications of Original Code
   9  * as defined in and that are subject to the Apple Public Source License
  10  * Version 2.0 (the 'License'). You may not use this file except in
  11  * compliance with the License. Please obtain a copy of the License at
  12  * http://www.opensource.apple.com/apsl/ and read it before using this
  13  * file.
  14  *
  15  * The Original Code and all software distributed under the License are
  16  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  17  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  18  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  20  * Please see the License for the specific language governing rights and
  21  * limitations under the License.
  22  *
  23  * @APPLE_LICENSE_HEADER_END@
  24  */
  25 /*
  26  * @OSF_COPYRIGHT@
  27  *
  28  */
  29 /*
  30  * HISTORY
  31  *
  32  * Revision 1.1.1.1  1998/09/22 21:05:31  wsanchez
  33  * Import of Mac OS X kernel (~semeria)
  34  *
  35  * Revision 1.1.1.1  1998/03/07 02:25:47  wsanchez
  36  * Import of OSF Mach kernel (~mburg)
  37  *
  38  * Revision 1.1.5.1  1995/06/13  18:20:42  sjs
  39  *      Merge from flipc_shared.
  40  *      [95/06/07            sjs]
  41  *
  42  * Revision 1.1.3.3  1995/02/21  17:23:16  randys
  43  *      Re-indented code to four space indentation
  44  *      [1995/02/21  16:26:50  randys]
  45  *
  46  * Revision 1.1.3.2  1994/12/20  19:02:12  randys
  47  *      Moved definition of flipc_simple_lock to flipc_cb.h
  48  *      [1994/12/20  17:35:15  randys]
  49  *
  50  *      Moved the machine independent macros into mach/flipc_locks.h
  51  *      [1994/12/20  16:44:14  randys]
  52  *
  53  *      Added filename in comment at top of file
  54  *      [1994/12/19  20:29:36  randys]
  55  *
  56  *      Fixed incorrect return of lock_try
  57  *      [1994/12/13  00:36:46  randys]
  58  *
  59  * Revision 1.1.3.1  1994/12/12  17:46:29  randys
  60  *      Putting initial flipc implementation under flipc_shared
  61  *      [1994/12/12  16:27:51  randys]
  62  *
  63  * Revision 1.1.1.2  1994/12/11  23:08:36  randys
  64  *      Initial flipc code checkin.
  65  *
  66  * $EndLog$
  67  */
  68
  69 /*
  70  * mach/i386/flipc_dep.h
  71  *
  72  * This file will have all of the FLIPC implementation machine dependent
  73  * defines that need to be visible to both kernel and AIL (eg. bus locks
  74  * and bus synchronization primitives).
  75  */
  76
  77 #ifndef _MACH_FLIPC_DEP_H_
  78 #define _MACH_FLIPC_DEP_H_
  79
  80 /* For the 386, we don't need to wrap synchronization variable writes
  81    at all.  */
  82 #define SYNCVAR_WRITE(statement)  statement
  83
  84 /* And similarly (I believe; check on this), for the 386 there isn't any
  85    requirement for write fences.  */
  86 #define WRITE_FENCE()
  87
  88 /*
  89  * Flipc simple lock defines.  These are almost completely for the use
  90  * of the AIL; the reason they are in this file is that they need to
  91  * be initialized properly in the communications buffer initialization
  92  * routine.  Sigh.  Note in particular that the kernel has no defined
  93  * "simple_lock_yield_function", so it had better never expand the
  94  * macro simple_lock_acquire.
  95  *
  96  * These locks may be declared by "flipc_simple_lock lock;".  If they
  97  * are instead declared by FLIPC_DECL_SIMPLE_LOCK(class,lockname) they
  98  * may be used without initialization.
  99  */
 100
 101 #define SIMPLE_LOCK_INITIALIZER 0
 102 #define FLIPC_DECL_SIMPLE_LOCK(class,lockname) \
 103 class flipc_simple_lock (lockname) = SIMPLE_LOCK_INITIALIZER
 104
 105 /*
 106  * Lower case because they may be macros or functions.
 107  * I'll include the function prototypes just for examples here.
 108  */
 109
 110 #define flipc_simple_lock_init(lock)            \
 111 do {                                            \
 112     *(lock) = SIMPLE_LOCK_INITIALIZER;          \
 113 } while (0)
 114
 115 /*
 116  * Defines of the actual routines, for gcc.
 117  */
 118
 119 #define flipc_simple_lock_locked(lock) ((*lock) != SIMPLE_LOCK_INITIALIZER)
 120
 121 #ifdef __GNUC__
 122      extern __inline__ int flipc_simple_lock_try(flipc_simple_lock *lock)
 123 {
 124     int r;
 125     __asm__ volatile("movl $1, %0; xchgl %0, %1" : "=&r" (r), "=m" (*lock));
 126     return !r;
 127 }
 128
 129 /* I don't know why this requires an ASM, but I'll follow the leader. */
 130 extern __inline__ void flipc_simple_lock_release(flipc_simple_lock *lock)
 131 {
 132     register int t;
 133
 134     __asm__ volatile("xorl %0, %0; xchgl %0, %1" : "=&r" (t), "=m" (*lock));
 135 }
 136 #else   /* __GNUC__ */
 137 /* If we aren't compiling with gcc, the above need to be functions.  */
 138 #endif  /* __GNUC__ */
 139
 140 #endif /* _MACH_FLIPC_DEP_H_ */