Define atomic_max and atomic_min.
[kopensolaris-gnu/glibc.git] / include / atomic.h
1 /* Internal macros for atomic operations for GNU C Library.
2    Copyright (C) 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
3    This file is part of the GNU C Library.
4    Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
5
6    The GNU C Library is free software; you can redistribute it and/or
7    modify it under the terms of the GNU Lesser General Public
8    License as published by the Free Software Foundation; either
9    version 2.1 of the License, or (at your option) any later version.
10
11    The GNU C Library is distributed in the hope that it will be useful,
12    but WITHOUT ANY WARRANTY; without even the implied warranty of
13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
14    Lesser General Public License for more details.
15
16    You should have received a copy of the GNU Lesser General Public
17    License along with the GNU C Library; if not, write to the Free
18    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
19    02111-1307 USA.  */
20
21 #ifndef _ATOMIC_H
22 #define _ATOMIC_H       1
23
24 #include <stdlib.h>
25
26 #include <bits/atomic.h>
27
28 /* Wrapper macros to call pre_NN_post (mem, ...) where NN is the
29    bit width of *MEM.  The calling macro puts parens around MEM
30    and following args.  */
31 #define __atomic_val_bysize(pre, post, mem, ...)                              \
32   ({                                                                          \
33     __typeof (*mem) __result;                                                 \
34     if (sizeof (*mem) == 1)                                                   \
35       __result = pre##_8_##post (mem, __VA_ARGS__);                           \
36     else if (sizeof (*mem) == 2)                                              \
37       __result = pre##_16_##post (mem, __VA_ARGS__);                          \
38     else if (sizeof (*mem) == 4)                                              \
39       __result = pre##_32_##post (mem, __VA_ARGS__);                          \
40     else if (sizeof (*mem) == 8)                                              \
41       __result = pre##_64_##post (mem, __VA_ARGS__);                          \
42     else                                                                      \
43       abort ();                                                               \
44     __result;                                                                 \
45   })
46 #define __atomic_bool_bysize(pre, post, mem, ...)                             \
47   ({                                                                          \
48     int __result;                                                             \
49     if (sizeof (*mem) == 1)                                                   \
50       __result = pre##_8_##post (mem, __VA_ARGS__);                           \
51     else if (sizeof (*mem) == 2)                                              \
52       __result = pre##_16_##post (mem, __VA_ARGS__);                          \
53     else if (sizeof (*mem) == 4)                                              \
54       __result = pre##_32_##post (mem, __VA_ARGS__);                          \
55     else if (sizeof (*mem) == 8)                                              \
56       __result = pre##_64_##post (mem, __VA_ARGS__);                          \
57     else                                                                      \
58       abort ();                                                               \
59     __result;                                                                 \
60   })
61
62
63 /* Atomically store NEWVAL in *MEM if *MEM is equal to OLDVAL.
64    Return the old *MEM value.  */
65 #if !defined atomic_compare_and_exchange_val_acq \
66     && defined __arch_compare_and_exchange_val_32_acq
67 # define atomic_compare_and_exchange_val_acq(mem, newval, oldval) \
68   __atomic_val_bysize (__arch_compare_and_exchange_val,acq,                   \
69                        mem, newval, oldval)
70 #endif
71
72
73 #ifndef atomic_compare_and_exchange_val_rel
74 # define atomic_compare_and_exchange_val_rel(mem, newval, oldval)             \
75   atomic_compare_and_exchange_val_acq (mem, newval, oldval)
76 #endif
77
78
79 /* Atomically store NEWVAL in *MEM if *MEM is equal to OLDVAL.
80    Return zero if *MEM was changed or non-zero if no exchange happened.  */
81 #ifndef atomic_compare_and_exchange_bool_acq
82 # ifdef __arch_compare_and_exchange_bool_32_acq
83 #  define atomic_compare_and_exchange_bool_acq(mem, newval, oldval) \
84   __atomic_bool_bysize (__arch_compare_and_exchange_bool,acq,                 \
85                         mem, newval, oldval)
86 #  else
87 #   define atomic_compare_and_exchange_bool_acq(mem, newval, oldval) \
88   ({ /* Cannot use __oldval here, because macros later in this file might     \
89         call this macro with __oldval argument.  */                           \
90      __typeof (oldval) __old = (oldval);                                      \
91      atomic_compare_and_exchange_val_acq (mem, newval, __old) != __old;       \
92   })
93 # endif
94 #endif
95
96
97 #ifndef atomic_compare_and_exchange_bool_rel
98 # define atomic_compare_and_exchange_bool_rel(mem, newval, oldval) \
99   atomic_compare_and_exchange_bool_acq (mem, newval, oldval)
100 #endif
101
102
103 /* Store NEWVALUE in *MEM and return the old value.  */
104 #ifndef atomic_exchange_acq
105 # define atomic_exchange_acq(mem, newvalue) \
106   ({ __typeof (*(mem)) __oldval;                                              \
107      __typeof (mem) __memp = (mem);                                           \
108      __typeof (*(mem)) __value = (newvalue);                                  \
109                                                                               \
110      do                                                                       \
111        __oldval = *__memp;                                                    \
112      while (__builtin_expect (atomic_compare_and_exchange_bool_acq (__memp,   \
113                                                                     __value,  \
114                                                                     __oldval),\
115                               0));                                            \
116                                                                               \
117      __oldval; })
118 #endif
119
120 #ifndef atomic_exchange_rel
121 # define atomic_exchange_rel(mem, newvalue) atomic_exchange_acq (mem, newvalue)
122 #endif
123
124
125 /* Add VALUE to *MEM and return the old value of *MEM.  */
126 #ifndef atomic_exchange_and_add
127 # define atomic_exchange_and_add(mem, value) \
128   ({ __typeof (*(mem)) __oldval;                                              \
129      __typeof (mem) __memp = (mem);                                           \
130      __typeof (*(mem)) __value = (value);                                     \
131                                                                               \
132      do                                                                       \
133        __oldval = *__memp;                                                    \
134      while (__builtin_expect (atomic_compare_and_exchange_bool_acq (__memp,   \
135                                                                     __oldval  \
136                                                                     + __value,\
137                                                                     __oldval),\
138                               0));                                            \
139                                                                               \
140      __oldval; })
141 #endif
142
143
144
145 #ifndef atomic_max
146 # define atomic_max(mem, value) \
147   do {                                                                        \
148     __typeof (*(mem)) __oldval;                                               \
149     __typeof (mem) __memp = (mem);                                            \
150     __typeof (*(mem)) __value = (value);                                      \
151     do {                                                                      \
152       __oldval = *__memp;                                                     \
153       if (__oldval >= __value)                                                \
154         break;                                                                \
155     } while (__builtin_expect (atomic_compare_and_exchange_bool_acq (__memp,  \
156                                                                      __value, \
157                                                                      __oldval),\
158                                0));                                           \
159   } while (0)
160 #endif
161
162 #ifndef atomic_min
163 # define atomic_min(mem, value) \
164   do {                                                                        \
165     __typeof (*(mem)) __oldval;                                               \
166     __typeof (mem) __memp = (mem);                                            \
167     __typeof (*(mem)) __value = (value);                                      \
168     do {                                                                      \
169       __oldval = *__memp;                                                     \
170       if (__oldval <= __value)                                                \
171         break;                                                                \
172     } while (__builtin_expect (atomic_compare_and_exchange_bool_acq (__memp,  \
173                                                                      __value, \
174                                                                      __oldval),\
175                                0));                                           \
176   } while (0)
177 #endif
178
179 #ifndef atomic_add
180 # define atomic_add(mem, value) (void) atomic_exchange_and_add ((mem), (value))
181 #endif
182
183
184 #ifndef atomic_increment
185 # define atomic_increment(mem) atomic_add ((mem), 1)
186 #endif
187
188
189 #ifndef atomic_increment_val
190 # define atomic_increment_val(mem) (atomic_exchange_and_add ((mem), 1) + 1)
191 #endif
192
193
194 /* Add one to *MEM and return true iff it's now zero.  */
195 #ifndef atomic_increment_and_test
196 # define atomic_increment_and_test(mem) \
197   (atomic_exchange_and_add ((mem), 1) + 1 == 0)
198 #endif
199
200
201 #ifndef atomic_decrement
202 # define atomic_decrement(mem) atomic_add ((mem), -1)
203 #endif
204
205
206 #ifndef atomic_decrement_val
207 # define atomic_decrement_val(mem) (atomic_exchange_and_add ((mem), -1) - 1)
208 #endif
209
210
211 /* Subtract 1 from *MEM and return true iff it's now zero.  */
212 #ifndef atomic_decrement_and_test
213 # define atomic_decrement_and_test(mem) \
214   (atomic_exchange_and_add ((mem), -1) == 1)
215 #endif
216
217
218 /* Decrement *MEM if it is > 0, and return the old value.  */
219 #ifndef atomic_decrement_if_positive
220 # define atomic_decrement_if_positive(mem) \
221   ({ __typeof (*(mem)) __oldval;                                              \
222      __typeof (mem) __memp = (mem);                                           \
223                                                                               \
224      do                                                                       \
225        {                                                                      \
226          __oldval = *__memp;                                                  \
227          if (__builtin_expect (__oldval <= 0, 0))                             \
228            break;                                                             \
229        }                                                                      \
230      while (__builtin_expect (atomic_compare_and_exchange_bool_acq (__memp,   \
231                                                                     __oldval  \
232                                                                     - 1,      \
233                                                                     __oldval),\
234                               0));\
235      __oldval; })
236 #endif
237
238
239 #ifndef atomic_add_negative
240 # define atomic_add_negative(mem, value)                                      \
241   ({ __typeof (value) __aan_value = (value);                                  \
242      atomic_exchange_and_add (mem, __aan_value) < -__aan_value; })
243 #endif
244
245
246 #ifndef atomic_add_zero
247 # define atomic_add_zero(mem, value)                                          \
248   ({ __typeof (value) __aaz_value = (value);                                  \
249      atomic_exchange_and_add (mem, __aaz_value) == -__aaz_value; })
250 #endif
251
252
253 #ifndef atomic_bit_set
254 # define atomic_bit_set(mem, bit) \
255   (void) atomic_bit_test_set(mem, bit)
256 #endif
257
258
259 #ifndef atomic_bit_test_set
260 # define atomic_bit_test_set(mem, bit) \
261   ({ __typeof (*(mem)) __oldval;                                              \
262      __typeof (mem) __memp = (mem);                                           \
263      __typeof (*(mem)) __mask = ((__typeof (*(mem))) 1 << (bit));             \
264                                                                               \
265      do                                                                       \
266        __oldval = (*__memp);                                                  \
267      while (__builtin_expect (atomic_compare_and_exchange_bool_acq (__memp,   \
268                                                                     __oldval  \
269                                                                     | __mask, \
270                                                                     __oldval),\
271                               0));                                            \
272                                                                               \
273      __oldval & __mask; })
274 #endif
275
276
277 #ifndef atomic_full_barrier
278 # define atomic_full_barrier() __asm ("" ::: "memory")
279 #endif
280
281
282 #ifndef atomic_read_barrier
283 # define atomic_read_barrier() atomic_full_barrier ()
284 #endif
285
286
287 #ifndef atomic_write_barrier
288 # define atomic_write_barrier() atomic_full_barrier ()
289 #endif
290
291
292 #ifndef atomic_delay
293 # define atomic_delay() do { /* nothing */ } while (0)
294 #endif
295
296 #endif  /* atomic.h */