about summary refs log tree commit diff
path: root/include/atomic.h
blob: 5a8e7e7966d6cab78ef918e98cc5797df0a2dc2e (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
/* Internal macros for atomic operations for GNU C Library.
   Copyright (C) 2002-2016 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, see
   <http://www.gnu.org/licenses/>.  */

#ifndef _ATOMIC_H
#define _ATOMIC_H	1

/* This header defines three types of macros:

   - atomic arithmetic and logic operation on memory.  They all
     have the prefix "atomic_".

   - conditionally atomic operations of the same kinds.  These
     always behave identical but can be faster when atomicity
     is not really needed since only one thread has access to
     the memory location.  In that case the code is slower in
     the multi-thread case.  The interfaces have the prefix
     "catomic_".

   - support functions like barriers.  They also have the prefix
     "atomic_".

   Architectures must provide a few lowlevel macros (the compare
   and exchange definitions).  All others are optional.  They
   should only be provided if the architecture has specific
   support for the operation.

   As <atomic.h> macros are usually heavily nested and often use local
   variables to make sure side-effects are evaluated properly, use for
   macro local variables a per-macro unique prefix.  This file uses
   __atgN_ prefix where N is different in each macro.  */

#include <stdlib.h>

#include <atomic-machine.h>

/* Wrapper macros to call pre_NN_post (mem, ...) where NN is the
   bit width of *MEM.  The calling macro puts parens around MEM
   and following args.  */
#define __atomic_val_bysize(pre, post, mem, ...)			      \
  ({									      \
    __typeof (*mem) __atg1_result;					      \
    if (sizeof (*mem) == 1)						      \
      __atg1_result = pre##_8_##post (mem, __VA_ARGS__);		      \
    else if (sizeof (*mem) == 2)					      \
      __atg1_result = pre##_16_##post (mem, __VA_ARGS__);		      \
    else if (sizeof (*mem) == 4)					      \
      __atg1_result = pre##_32_##post (mem, __VA_ARGS__);		      \
    else if (sizeof (*mem) == 8)					      \
      __atg1_result = pre##_64_##post (mem, __VA_ARGS__);		      \
    else								      \
      abort ();								      \
    __atg1_result;							      \
  })
#define __atomic_bool_bysize(pre, post, mem, ...)			      \
  ({									      \
    int __atg2_result;							      \
    if (sizeof (*mem) == 1)						      \
      __atg2_result = pre##_8_##post (mem, __VA_ARGS__);		      \
    else if (sizeof (*mem) == 2)					      \
      __atg2_result = pre##_16_##post (mem, __VA_ARGS__);		      \
    else if (sizeof (*mem) == 4)					      \
      __atg2_result = pre##_32_##post (mem, __VA_ARGS__);		      \
    else if (sizeof (*mem) == 8)					      \
      __atg2_result = pre##_64_##post (mem, __VA_ARGS__);		      \
    else								      \
      abort ();								      \
    __atg2_result;							      \
  })


/* Atomically store NEWVAL in *MEM if *MEM is equal to OLDVAL.
   Return the old *MEM value.  */
#if !defined atomic_compare_and_exchange_val_acq \
    && defined __arch_compare_and_exchange_val_32_acq
# define atomic_compare_and_exchange_val_acq(mem, newval, oldval) \
  __atomic_val_bysize (__arch_compare_and_exchange_val,acq,		      \
		       mem, newval, oldval)
#endif


#ifndef catomic_compare_and_exchange_val_acq
# ifdef __arch_c_compare_and_exchange_val_32_acq
#  define catomic_compare_and_exchange_val_acq(mem, newval, oldval) \
  __atomic_val_bysize (__arch_c_compare_and_exchange_val,acq,		      \
		       mem, newval, oldval)
# else
#  define catomic_compare_and_exchange_val_acq(mem, newval, oldval) \
  atomic_compare_and_exchange_val_acq (mem, newval, oldval)
# endif
#endif


#ifndef catomic_compare_and_exchange_val_rel
# ifndef atomic_compare_and_exchange_val_rel
#  define catomic_compare_and_exchange_val_rel(mem, newval, oldval)	      \
  catomic_compare_and_exchange_val_acq (mem, newval, oldval)
# else
#  define catomic_compare_and_exchange_val_rel(mem, newval, oldval)	      \
  atomic_compare_and_exchange_val_rel (mem, newval, oldval)
# endif
#endif


#ifndef atomic_compare_and_exchange_val_rel
# define atomic_compare_and_exchange_val_rel(mem, newval, oldval)	      \
  atomic_compare_and_exchange_val_acq (mem, newval, oldval)
#endif


/* Atomically store NEWVAL in *MEM if *MEM is equal to OLDVAL.
   Return zero if *MEM was changed or non-zero if no exchange happened.  */
#ifndef atomic_compare_and_exchange_bool_acq
# ifdef __arch_compare_and_exchange_bool_32_acq
#  define atomic_compare_and_exchange_bool_acq(mem, newval, oldval) \
  __atomic_bool_bysize (__arch_compare_and_exchange_bool,acq,		      \
		        mem, newval, oldval)
# else
#  define atomic_compare_and_exchange_bool_acq(mem, newval, oldval) \
  ({ /* Cannot use __oldval here, because macros later in this file might     \
	call this macro with __oldval argument.	 */			      \
     __typeof (oldval) __atg3_old = (oldval);				      \
     atomic_compare_and_exchange_val_acq (mem, newval, __atg3_old)	      \
       != __atg3_old;							      \
  })
# endif
#endif


#ifndef catomic_compare_and_exchange_bool_acq
# ifdef __arch_c_compare_and_exchange_bool_32_acq
#  define catomic_compare_and_exchange_bool_acq(mem, newval, oldval) \
  __atomic_bool_bysize (__arch_c_compare_and_exchange_bool,acq,		      \
		        mem, newval, oldval)
# else
#  define catomic_compare_and_exchange_bool_acq(mem, newval, oldval) \
  ({ /* Cannot use __oldval here, because macros later in this file might     \
	call this macro with __oldval argument.	 */			      \
     __typeof (oldval) __atg4_old = (oldval);				      \
     catomic_compare_and_exchange_val_acq (mem, newval, __atg4_old)	      \
       != __atg4_old;							      \
  })
# endif
#endif


/* Store NEWVALUE in *MEM and return the old value.  */
#ifndef atomic_exchange_acq
# define atomic_exchange_acq(mem, newvalue) \
  ({ __typeof (*(mem)) __atg5_oldval;					      \
     __typeof (mem) __atg5_memp = (mem);				      \
     __typeof (*(mem)) __atg5_value = (newvalue);			      \
									      \
     do									      \
       __atg5_oldval = *__atg5_memp;					      \
     while (__builtin_expect						      \
	    (atomic_compare_and_exchange_bool_acq (__atg5_memp, __atg5_value, \
						   __atg5_oldval), 0));	      \
									      \
     __atg5_oldval; })
#endif

#ifndef atomic_exchange_rel
# define atomic_exchange_rel(mem, newvalue) atomic_exchange_acq (mem, newvalue)
#endif


/* Add VALUE to *MEM and return the old value of *MEM.  */
#ifndef atomic_exchange_and_add_acq
# ifdef atomic_exchange_and_add
#  define atomic_exchange_and_add_acq(mem, value) \
  atomic_exchange_and_add (mem, value)
# else
#  define atomic_exchange_and_add_acq(mem, value) \
  ({ __typeof (*(mem)) __atg6_oldval;					      \
     __typeof (mem) __atg6_memp = (mem);				      \
     __typeof (*(mem)) __atg6_value = (value);				      \
									      \
     do									      \
       __atg6_oldval = *__atg6_memp;					      \
     while (__builtin_expect						      \
	    (atomic_compare_and_exchange_bool_acq (__atg6_memp,		      \
						   __atg6_oldval	      \
						   + __atg6_value,	      \
						   __atg6_oldval), 0));	      \
									      \
     __atg6_oldval; })
# endif
#endif

#ifndef atomic_exchange_and_add_rel
# define atomic_exchange_and_add_rel(mem, value) \
  atomic_exchange_and_add_acq(mem, value)
#endif

#ifndef atomic_exchange_and_add
# define atomic_exchange_and_add(mem, value) \
  atomic_exchange_and_add_acq(mem, value)
#endif

#ifndef catomic_exchange_and_add
# define catomic_exchange_and_add(mem, value) \
  ({ __typeof (*(mem)) __atg7_oldv;					      \
     __typeof (mem) __atg7_memp = (mem);				      \
     __typeof (*(mem)) __atg7_value = (value);				      \
									      \
     do									      \
       __atg7_oldv = *__atg7_memp;					      \
     while (__builtin_expect						      \
	    (catomic_compare_and_exchange_bool_acq (__atg7_memp,	      \
						    __atg7_oldv		      \
						    + __atg7_value,	      \
						    __atg7_oldv), 0));	      \
									      \
     __atg7_oldv; })
#endif


#ifndef atomic_max
# define atomic_max(mem, value) \
  do {									      \
    __typeof (*(mem)) __atg8_oldval;					      \
    __typeof (mem) __atg8_memp = (mem);					      \
    __typeof (*(mem)) __atg8_value = (value);				      \
    do {								      \
      __atg8_oldval = *__atg8_memp;					      \
      if (__atg8_oldval >= __atg8_value)				      \
	break;								      \
    } while (__builtin_expect						      \
	     (atomic_compare_and_exchange_bool_acq (__atg8_memp, __atg8_value,\
						    __atg8_oldval), 0));      \
  } while (0)
#endif


#ifndef catomic_max
# define catomic_max(mem, value) \
  do {									      \
    __typeof (*(mem)) __atg9_oldv;					      \
    __typeof (mem) __atg9_memp = (mem);					      \
    __typeof (*(mem)) __atg9_value = (value);				      \
    do {								      \
      __atg9_oldv = *__atg9_memp;					      \
      if (__atg9_oldv >= __atg9_value)					      \
	break;								      \
    } while (__builtin_expect						      \
	     (catomic_compare_and_exchange_bool_acq (__atg9_memp,	      \
						     __atg9_value,	      \
						     __atg9_oldv), 0));	      \
  } while (0)
#endif


#ifndef atomic_min
# define atomic_min(mem, value) \
  do {									      \
    __typeof (*(mem)) __atg10_oldval;					      \
    __typeof (mem) __atg10_memp = (mem);				      \
    __typeof (*(mem)) __atg10_value = (value);				      \
    do {								      \
      __atg10_oldval = *__atg10_memp;					      \
      if (__atg10_oldval <= __atg10_value)				      \
	break;								      \
    } while (__builtin_expect						      \
	     (atomic_compare_and_exchange_bool_acq (__atg10_memp,	      \
						    __atg10_value,	      \
						    __atg10_oldval), 0));     \
  } while (0)
#endif


#ifndef atomic_add
# define atomic_add(mem, value) (void) atomic_exchange_and_add ((mem), (value))
#endif


#ifndef catomic_add
# define catomic_add(mem, value) \
  (void) catomic_exchange_and_add ((mem), (value))
#endif


#ifndef atomic_increment
# define atomic_increment(mem) atomic_add ((mem), 1)
#endif


#ifndef catomic_increment
# define catomic_increment(mem) catomic_add ((mem), 1)
#endif


#ifndef atomic_increment_val
# define atomic_increment_val(mem) (atomic_exchange_and_add ((mem), 1) + 1)
#endif


#ifndef catomic_increment_val
# define catomic_increment_val(mem) (catomic_exchange_and_add ((mem), 1) + 1)
#endif


/* Add one to *MEM and return true iff it's now zero.  */
#ifndef atomic_increment_and_test
# define atomic_increment_and_test(mem) \
  (atomic_exchange_and_add ((mem), 1) + 1 == 0)
#endif


#ifndef atomic_decrement
# define atomic_decrement(mem) atomic_add ((mem), -1)
#endif


#ifndef catomic_decrement
# define catomic_decrement(mem) catomic_add ((mem), -1)
#endif


#ifndef atomic_decrement_val
# define atomic_decrement_val(mem) (atomic_exchange_and_add ((mem), -1) - 1)
#endif


#ifndef catomic_decrement_val
# define catomic_decrement_val(mem) (catomic_exchange_and_add ((mem), -1) - 1)
#endif


/* Subtract 1 from *MEM and return true iff it's now zero.  */
#ifndef atomic_decrement_and_test
# define atomic_decrement_and_test(mem) \
  (atomic_exchange_and_add ((mem), -1) == 1)
#endif


/* Decrement *MEM if it is > 0, and return the old value.  */
#ifndef atomic_decrement_if_positive
# define atomic_decrement_if_positive(mem) \
  ({ __typeof (*(mem)) __atg11_oldval;					      \
     __typeof (mem) __atg11_memp = (mem);				      \
									      \
     do									      \
       {								      \
	 __atg11_oldval = *__atg11_memp;				      \
	 if (__glibc_unlikely (__atg11_oldval <= 0))			      \
	   break;							      \
       }								      \
     while (__builtin_expect						      \
	    (atomic_compare_and_exchange_bool_acq (__atg11_memp,	      \
						   __atg11_oldval - 1,	      \
						   __atg11_oldval), 0));      \
     __atg11_oldval; })
#endif


#ifndef atomic_add_negative
# define atomic_add_negative(mem, value)				      \
  ({ __typeof (value) __atg12_value = (value);				      \
     atomic_exchange_and_add (mem, __atg12_value) < -__atg12_value; })
#endif


#ifndef atomic_add_zero
# define atomic_add_zero(mem, value)					      \
  ({ __typeof (value) __atg13_value = (value);				      \
     atomic_exchange_and_add (mem, __atg13_value) == -__atg13_value; })
#endif


#ifndef atomic_bit_set
# define atomic_bit_set(mem, bit) \
  (void) atomic_bit_test_set(mem, bit)
#endif


#ifndef atomic_bit_test_set
# define atomic_bit_test_set(mem, bit) \
  ({ __typeof (*(mem)) __atg14_old;					      \
     __typeof (mem) __atg14_memp = (mem);				      \
     __typeof (*(mem)) __atg14_mask = ((__typeof (*(mem))) 1 << (bit));	      \
									      \
     do									      \
       __atg14_old = (*__atg14_memp);					      \
     while (__builtin_expect						      \
	    (atomic_compare_and_exchange_bool_acq (__atg14_memp,	      \
						   __atg14_old | __atg14_mask,\
						   __atg14_old), 0));	      \
									      \
     __atg14_old & __atg14_mask; })
#endif

/* Atomically *mem &= mask.  */
#ifndef atomic_and
# define atomic_and(mem, mask) \
  do {									      \
    __typeof (*(mem)) __atg15_old;					      \
    __typeof (mem) __atg15_memp = (mem);				      \
    __typeof (*(mem)) __atg15_mask = (mask);				      \
									      \
    do									      \
      __atg15_old = (*__atg15_memp);					      \
    while (__builtin_expect						      \
	   (atomic_compare_and_exchange_bool_acq (__atg15_memp,		      \
						  __atg15_old & __atg15_mask, \
						  __atg15_old), 0));	      \
  } while (0)
#endif

#ifndef catomic_and
# define catomic_and(mem, mask) \
  do {									      \
    __typeof (*(mem)) __atg20_old;					      \
    __typeof (mem) __atg20_memp = (mem);				      \
    __typeof (*(mem)) __atg20_mask = (mask);				      \
									      \
    do									      \
      __atg20_old = (*__atg20_memp);					      \
    while (__builtin_expect						      \
	   (catomic_compare_and_exchange_bool_acq (__atg20_memp,	      \
						   __atg20_old & __atg20_mask,\
						   __atg20_old), 0));	      \
  } while (0)
#endif

/* Atomically *mem &= mask and return the old value of *mem.  */
#ifndef atomic_and_val
# define atomic_and_val(mem, mask) \
  ({ __typeof (*(mem)) __atg16_old;					      \
     __typeof (mem) __atg16_memp = (mem);				      \
     __typeof (*(mem)) __atg16_mask = (mask);				      \
									      \
     do									      \
       __atg16_old = (*__atg16_memp);					      \
     while (__builtin_expect						      \
	    (atomic_compare_and_exchange_bool_acq (__atg16_memp,	      \
						   __atg16_old & __atg16_mask,\
						   __atg16_old), 0));	      \
									      \
     __atg16_old; })
#endif

/* Atomically *mem |= mask and return the old value of *mem.  */
#ifndef atomic_or
# define atomic_or(mem, mask) \
  do {									      \
    __typeof (*(mem)) __atg17_old;					      \
    __typeof (mem) __atg17_memp = (mem);				      \
    __typeof (*(mem)) __atg17_mask = (mask);				      \
									      \
    do									      \
      __atg17_old = (*__atg17_memp);					      \
    while (__builtin_expect						      \
	   (atomic_compare_and_exchange_bool_acq (__atg17_memp,		      \
						  __atg17_old | __atg17_mask, \
						  __atg17_old), 0));	      \
  } while (0)
#endif

#ifndef catomic_or
# define catomic_or(mem, mask) \
  do {									      \
    __typeof (*(mem)) __atg18_old;					      \
    __typeof (mem) __atg18_memp = (mem);				      \
    __typeof (*(mem)) __atg18_mask = (mask);				      \
									      \
    do									      \
      __atg18_old = (*__atg18_memp);					      \
    while (__builtin_expect						      \
	   (catomic_compare_and_exchange_bool_acq (__atg18_memp,	      \
						   __atg18_old | __atg18_mask,\
						   __atg18_old), 0));	      \
  } while (0)
#endif

/* Atomically *mem |= mask and return the old value of *mem.  */
#ifndef atomic_or_val
# define atomic_or_val(mem, mask) \
  ({ __typeof (*(mem)) __atg19_old;					      \
     __typeof (mem) __atg19_memp = (mem);				      \
     __typeof (*(mem)) __atg19_mask = (mask);				      \
									      \
     do									      \
       __atg19_old = (*__atg19_memp);					      \
     while (__builtin_expect						      \
	    (atomic_compare_and_exchange_bool_acq (__atg19_memp,	      \
						   __atg19_old | __atg19_mask,\
						   __atg19_old), 0));	      \
									      \
     __atg19_old; })
#endif

#ifndef atomic_full_barrier
# define atomic_full_barrier() __asm ("" ::: "memory")
#endif


#ifndef atomic_read_barrier
# define atomic_read_barrier() atomic_full_barrier ()
#endif


#ifndef atomic_write_barrier
# define atomic_write_barrier() atomic_full_barrier ()
#endif


#ifndef atomic_forced_read
# define atomic_forced_read(x) \
  ({ __typeof (x) __x; __asm ("" : "=r" (__x) : "0" (x)); __x; })
#endif

/* This is equal to 1 iff the architecture supports 64b atomic operations.  */
#ifndef __HAVE_64B_ATOMICS
#error Unable to determine if 64-bit atomics are present.
#endif

/* The following functions are a subset of the atomic operations provided by
   C11.  Usually, a function named atomic_OP_MO(args) is equivalent to C11's
   atomic_OP_explicit(args, memory_order_MO); exceptions noted below.  */

/* Each arch can request to use compiler built-ins for C11 atomics.  If it
   does, all atomics will be based on these.  */
#if USE_ATOMIC_COMPILER_BUILTINS

/* We require 32b atomic operations; some archs also support 64b atomic
   operations.  */
void __atomic_link_error (void);
# if __HAVE_64B_ATOMICS == 1
#  define __atomic_check_size(mem) \
   if ((sizeof (*mem) != 4) && (sizeof (*mem) != 8))			      \
     __atomic_link_error ();
# else
#  define __atomic_check_size(mem) \
   if (sizeof (*mem) != 4)						      \
     __atomic_link_error ();
# endif

# define atomic_thread_fence_acquire() \
  __atomic_thread_fence (__ATOMIC_ACQUIRE)
# define atomic_thread_fence_release() \
  __atomic_thread_fence (__ATOMIC_RELEASE)
# define atomic_thread_fence_seq_cst() \
  __atomic_thread_fence (__ATOMIC_SEQ_CST)

# define atomic_load_relaxed(mem) \
  ({ __atomic_check_size((mem)); __atomic_load_n ((mem), __ATOMIC_RELAXED); })
# define atomic_load_acquire(mem) \
  ({ __atomic_check_size((mem)); __atomic_load_n ((mem), __ATOMIC_ACQUIRE); })

# define atomic_store_relaxed(mem, val) \
  do {									      \
    __atomic_check_size((mem));						      \
    __atomic_store_n ((mem), (val), __ATOMIC_RELAXED);			      \
  } while (0)
# define atomic_store_release(mem, val) \
  do {									      \
    __atomic_check_size((mem));						      \
    __atomic_store_n ((mem), (val), __ATOMIC_RELEASE);			      \
  } while (0)

/* On failure, this CAS has memory_order_relaxed semantics.  */
# define atomic_compare_exchange_weak_relaxed(mem, expected, desired) \
  ({ __atomic_check_size((mem));					      \
  __atomic_compare_exchange_n ((mem), (expected), (desired), 1,		      \
    __ATOMIC_RELAXED, __ATOMIC_RELAXED); })
# define atomic_compare_exchange_weak_acquire(mem, expected, desired) \
  ({ __atomic_check_size((mem));					      \
  __atomic_compare_exchange_n ((mem), (expected), (desired), 1,		      \
    __ATOMIC_ACQUIRE, __ATOMIC_RELAXED); })
# define atomic_compare_exchange_weak_release(mem, expected, desired) \
  ({ __atomic_check_size((mem));					      \
  __atomic_compare_exchange_n ((mem), (expected), (desired), 1,		      \
    __ATOMIC_RELEASE, __ATOMIC_RELAXED); })

# define atomic_exchange_relaxed(mem, desired) \
  ({ __atomic_check_size((mem));					      \
  __atomic_exchange_n ((mem), (desired), __ATOMIC_RELAXED); })
# define atomic_exchange_acquire(mem, desired) \
  ({ __atomic_check_size((mem));					      \
  __atomic_exchange_n ((mem), (desired), __ATOMIC_ACQUIRE); })
# define atomic_exchange_release(mem, desired) \
  ({ __atomic_check_size((mem));					      \
  __atomic_exchange_n ((mem), (desired), __ATOMIC_RELEASE); })

# define atomic_fetch_add_relaxed(mem, operand) \
  ({ __atomic_check_size((mem));					      \
  __atomic_fetch_add ((mem), (operand), __ATOMIC_RELAXED); })
# define atomic_fetch_add_acquire(mem, operand) \
  ({ __atomic_check_size((mem));					      \
  __atomic_fetch_add ((mem), (operand), __ATOMIC_ACQUIRE); })
# define atomic_fetch_add_release(mem, operand) \
  ({ __atomic_check_size((mem));					      \
  __atomic_fetch_add ((mem), (operand), __ATOMIC_RELEASE); })
# define atomic_fetch_add_acq_rel(mem, operand) \
  ({ __atomic_check_size((mem));					      \
  __atomic_fetch_add ((mem), (operand), __ATOMIC_ACQ_REL); })

# define atomic_fetch_and_relaxed(mem, operand) \
  ({ __atomic_check_size((mem));					      \
  __atomic_fetch_and ((mem), (operand), __ATOMIC_RELAXED); })
# define atomic_fetch_and_acquire(mem, operand) \
  ({ __atomic_check_size((mem));					      \
  __atomic_fetch_and ((mem), (operand), __ATOMIC_ACQUIRE); })
# define atomic_fetch_and_release(mem, operand) \
  ({ __atomic_check_size((mem));					      \
  __atomic_fetch_and ((mem), (operand), __ATOMIC_RELEASE); })

# define atomic_fetch_or_relaxed(mem, operand) \
  ({ __atomic_check_size((mem));					      \
  __atomic_fetch_or ((mem), (operand), __ATOMIC_RELAXED); })
# define atomic_fetch_or_acquire(mem, operand) \
  ({ __atomic_check_size((mem));					      \
  __atomic_fetch_or ((mem), (operand), __ATOMIC_ACQUIRE); })
# define atomic_fetch_or_release(mem, operand) \
  ({ __atomic_check_size((mem));					      \
  __atomic_fetch_or ((mem), (operand), __ATOMIC_RELEASE); })

# define atomic_fetch_xor_release(mem, operand) \
  ({ __atomic_check_size((mem));					      \
  __atomic_fetch_xor ((mem), (operand), __ATOMIC_RELEASE); })

#else /* !USE_ATOMIC_COMPILER_BUILTINS  */

/* By default, we assume that read, write, and full barriers are equivalent
   to acquire, release, and seq_cst barriers.  Archs for which this does not
   hold have to provide custom definitions of the fences.  */
# ifndef atomic_thread_fence_acquire
#  define atomic_thread_fence_acquire() atomic_read_barrier ()
# endif
# ifndef atomic_thread_fence_release
#  define atomic_thread_fence_release() atomic_write_barrier ()
# endif
# ifndef atomic_thread_fence_seq_cst
#  define atomic_thread_fence_seq_cst() atomic_full_barrier ()
# endif

# ifndef atomic_load_relaxed
#  define atomic_load_relaxed(mem) \
   ({ __typeof (*(mem)) __atg100_val;					      \
   __asm ("" : "=r" (__atg100_val) : "0" (*(mem)));			      \
   __atg100_val; })
# endif
# ifndef atomic_load_acquire
#  define atomic_load_acquire(mem) \
   ({ __typeof (*(mem)) __atg101_val = atomic_load_relaxed (mem);	      \
   atomic_thread_fence_acquire ();					      \
   __atg101_val; })
# endif

# ifndef atomic_store_relaxed
/* XXX Use inline asm here?  */
#  define atomic_store_relaxed(mem, val) do { *(mem) = (val); } while (0)
# endif
# ifndef atomic_store_release
#  define atomic_store_release(mem, val) \
   do {									      \
     atomic_thread_fence_release ();					      \
     atomic_store_relaxed ((mem), (val));				      \
   } while (0)
# endif

/* On failure, this CAS has memory_order_relaxed semantics.  */
/* XXX This potentially has one branch more than necessary, but archs
   currently do not define a CAS that returns both the previous value and
   the success flag.  */
# ifndef atomic_compare_exchange_weak_acquire
#  define atomic_compare_exchange_weak_acquire(mem, expected, desired) \
   ({ typeof (*(expected)) __atg102_expected = *(expected);		      \
   *(expected) =							      \
     atomic_compare_and_exchange_val_acq ((mem), (desired), *(expected));     \
   *(expected) == __atg102_expected; })
# endif
# ifndef atomic_compare_exchange_weak_relaxed
/* XXX Fall back to CAS with acquire MO because archs do not define a weaker
   CAS.  */
#  define atomic_compare_exchange_weak_relaxed(mem, expected, desired) \
   atomic_compare_exchange_weak_acquire ((mem), (expected), (desired))
# endif
# ifndef atomic_compare_exchange_weak_release
#  define atomic_compare_exchange_weak_release(mem, expected, desired) \
   ({ typeof (*(expected)) __atg103_expected = *(expected);		      \
   *(expected) =							      \
     atomic_compare_and_exchange_val_rel ((mem), (desired), *(expected));     \
   *(expected) == __atg103_expected; })
# endif

/* XXX Fall back to acquire MO because archs do not define a weaker
   atomic_exchange.  */
# ifndef atomic_exchange_relaxed
#  define atomic_exchange_relaxed(mem, val) \
   atomic_exchange_acq ((mem), (val))
# endif
# ifndef atomic_exchange_acquire
#  define atomic_exchange_acquire(mem, val) \
   atomic_exchange_acq ((mem), (val))
# endif
# ifndef atomic_exchange_release
#  define atomic_exchange_release(mem, val) \
   atomic_exchange_rel ((mem), (val))
# endif

# ifndef atomic_fetch_add_acquire
#  define atomic_fetch_add_acquire(mem, operand) \
   atomic_exchange_and_add_acq ((mem), (operand))
# endif
# ifndef atomic_fetch_add_relaxed
/* XXX Fall back to acquire MO because the MO semantics of
   atomic_exchange_and_add are not documented; the generic version falls back
   to atomic_exchange_and_add_acq if atomic_exchange_and_add is not defined,
   and vice versa.  */
#  define atomic_fetch_add_relaxed(mem, operand) \
   atomic_fetch_add_acquire ((mem), (operand))
# endif
# ifndef atomic_fetch_add_release
#  define atomic_fetch_add_release(mem, operand) \
   atomic_exchange_and_add_rel ((mem), (operand))
# endif
# ifndef atomic_fetch_add_acq_rel
#  define atomic_fetch_add_acq_rel(mem, operand) \
   ({ atomic_thread_fence_release ();					      \
   atomic_exchange_and_add_acq ((mem), (operand)); })
# endif

/* XXX Fall back to acquire MO because archs do not define a weaker
   atomic_and_val.  */
# ifndef atomic_fetch_and_relaxed
#  define atomic_fetch_and_relaxed(mem, operand) \
   atomic_fetch_and_acquire ((mem), (operand))
# endif
/* XXX The default for atomic_and_val has acquire semantics, but this is not
   documented.  */
# ifndef atomic_fetch_and_acquire
#  define atomic_fetch_and_acquire(mem, operand) \
   atomic_and_val ((mem), (operand))
# endif
# ifndef atomic_fetch_and_release
/* XXX This unnecessarily has acquire MO.  */
#  define atomic_fetch_and_release(mem, operand) \
   ({ atomic_thread_fence_release ();					      \
   atomic_and_val ((mem), (operand)); })
# endif

/* XXX The default for atomic_or_val has acquire semantics, but this is not
   documented.  */
# ifndef atomic_fetch_or_acquire
#  define atomic_fetch_or_acquire(mem, operand) \
   atomic_or_val ((mem), (operand))
# endif
/* XXX Fall back to acquire MO because archs do not define a weaker
   atomic_or_val.  */
# ifndef atomic_fetch_or_relaxed
#  define atomic_fetch_or_relaxed(mem, operand) \
   atomic_fetch_or_acquire ((mem), (operand))
# endif
/* XXX Contains an unnecessary acquire MO because archs do not define a weaker
   atomic_or_val.  */
# ifndef atomic_fetch_or_release
#  define atomic_fetch_or_release(mem, operand) \
   ({ atomic_thread_fence_release ();					      \
   atomic_fetch_or_acquire ((mem), (operand)); })
# endif

# ifndef atomic_fetch_xor_release
# define atomic_fetch_xor_release(mem, operand) \
  ({ __typeof (*(mem)) __atg104_old;					      \
     __typeof (mem) __atg104_memp = (mem);				      \
     __typeof (*(mem)) __atg104_op = (operand);				      \
									      \
     do									      \
       __atg104_old = (*__atg104_memp);					      \
     while (__builtin_expect						      \
	    (atomic_compare_and_exchange_bool_rel (			      \
		__atg104_memp, __atg104_old ^ __atg104_op, __atg104_old), 0));\
									      \
     __atg104_old; })
#endif

#endif /* !USE_ATOMIC_COMPILER_BUILTINS  */

/* This operation does not affect synchronization semantics but can be used
   in the body of a spin loop to potentially improve its efficiency.  */
#ifndef atomic_spin_nop
# define atomic_spin_nop() do { /* nothing */ } while (0)
#endif

#endif	/* atomic.h */