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  * The contents of this file constitute Original Code as defined in and
   7  * are subject to the Apple Public Source License Version 1.1 (the
   8  * "License").  You may not use this file except in compliance with the
   9  * License.  Please obtain a copy of the License at
  10  * http://www.apple.com/publicsource and read it before using this file.
  11  *
  12  * This Original Code and all software distributed under the License are
  13  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  14  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  15  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
  17  * License for the specific language governing rights and limitations
  18  * under the License.
  19  *
  20  * @APPLE_LICENSE_HEADER_END@
  21  */
  22 /*
  23  * @OSF_COPYRIGHT@
  24  *
  25  */
  26 /*
  27  * HISTORY
  28  *
  29  * Revision 1.1.1.1  1998/09/22 21:05:31  wsanchez
  30  * Import of Mac OS X kernel (~semeria)
  31  *
  32  * Revision 1.1.1.1  1998/03/07 02:25:47  wsanchez
  33  * Import of OSF Mach kernel (~mburg)
  34  *
  35  * Revision 1.1.5.1  1995/06/13  18:20:42  sjs
  36  *      Merge from flipc_shared.
  37  *      [95/06/07            sjs]
  38  *
  39  * Revision 1.1.3.3  1995/02/21  17:23:16  randys
  40  *      Re-indented code to four space indentation
  41  *      [1995/02/21  16:26:50  randys]
  42  *
  43  * Revision 1.1.3.2  1994/12/20  19:02:12  randys
  44  *      Moved definition of flipc_simple_lock to flipc_cb.h
  45  *      [1994/12/20  17:35:15  randys]
  46  *
  47  *      Moved the machine independent macros into mach/flipc_locks.h
  48  *      [1994/12/20  16:44:14  randys]
  49  *
  50  *      Added filename in comment at top of file
  51  *      [1994/12/19  20:29:36  randys]
  52  *
  53  *      Fixed incorrect return of lock_try
  54  *      [1994/12/13  00:36:46  randys]
  55  *
  56  * Revision 1.1.3.1  1994/12/12  17:46:29  randys
  57  *      Putting initial flipc implementation under flipc_shared
  58  *      [1994/12/12  16:27:51  randys]
  59  *
  60  * Revision 1.1.1.2  1994/12/11  23:08:36  randys
  61  *      Initial flipc code checkin.
  62  *
  63  * $EndLog$
  64  */
  65
  66 /*
  67  * mach/i386/flipc_dep.h
  68  *
  69  * This file will have all of the FLIPC implementation machine dependent
  70  * defines that need to be visible to both kernel and AIL (eg. bus locks
  71  * and bus synchronization primitives).
  72  */
  73
  74 #ifndef _MACH_FLIPC_DEP_H_
  75 #define _MACH_FLIPC_DEP_H_
  76
  77 /* For the 386, we don't need to wrap synchronization variable writes
  78    at all.  */
  79 #define SYNCVAR_WRITE(statement)  statement
  80
  81 /* And similarly (I believe; check on this), for the 386 there isn't any
  82    requirement for write fences.  */
  83 #define WRITE_FENCE()
  84
  85 /*
  86  * Flipc simple lock defines.  These are almost completely for the use
  87  * of the AIL; the reason they are in this file is that they need to
  88  * be initialized properly in the communications buffer initialization
  89  * routine.  Sigh.  Note in particular that the kernel has no defined
  90  * "simple_lock_yield_function", so it had better never expand the
  91  * macro simple_lock_acquire.
  92  *
  93  * These locks may be declared by "flipc_simple_lock lock;".  If they
  94  * are instead declared by FLIPC_DECL_SIMPLE_LOCK(class,lockname) they
  95  * may be used without initialization.
  96  */
  97
  98 #define SIMPLE_LOCK_INITIALIZER 0
  99 #define FLIPC_DECL_SIMPLE_LOCK(class,lockname) \
 100 class flipc_simple_lock (lockname) = SIMPLE_LOCK_INITIALIZER
 101
 102 /*
 103  * Lower case because they may be macros or functions.
 104  * I'll include the function prototypes just for examples here.
 105  */
 106
 107 #define flipc_simple_lock_init(lock)            \
 108 do {                                            \
 109     *(lock) = SIMPLE_LOCK_INITIALIZER;          \
 110 } while (0)
 111
 112 /*
 113  * Defines of the actual routines, for gcc.
 114  */
 115
 116 #define flipc_simple_lock_locked(lock) ((*lock) != SIMPLE_LOCK_INITIALIZER)
 117
 118 #ifdef __GNUC__
 119      extern __inline__ int flipc_simple_lock_try(flipc_simple_lock *lock)
 120 {
 121     int r;
 122     __asm__ volatile("movl $1, %0; xchgl %0, %1" : "=&r" (r), "=m" (*lock));
 123     return !r;
 124 }
 125
 126 /* I don't know why this requires an ASM, but I'll follow the leader. */
 127 extern __inline__ void flipc_simple_lock_release(flipc_simple_lock *lock)
 128 {
 129     register int t;
 130
 131     __asm__ volatile("xorl %0, %0; xchgl %0, %1" : "=&r" (t), "=m" (*lock));
 132 }
 133 #else   /* __GNUC__ */
 134 /* If we aren't compiling with gcc, the above need to be functions.  */
 135 #endif  /* __GNUC__ */
 136
 137 #endif /* _MACH_FLIPC_DEP_H_ */