xf86atomic.h

   1 /*
   2  * Copyright © 2009 Intel Corporation
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a
   5  * copy of this software and associated documentation files (the "Software"),
   6  * to deal in the Software without restriction, including without limitation
   7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   8  * and/or sell copies of the Software, and to permit persons to whom the
   9  * Software is furnished to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice (including the next
  12  * paragraph) shall be included in all copies or substantial portions of the
  13  * Software.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  18  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  19  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  20  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  21  * IN THE SOFTWARE.
  22  *
  23  * Authors:
  24  *    Chris Wilson <chris@chris-wilson.co.uk>
  25  *
  26  */
  27
  28 /**
  29  * @file xf86atomics.h
  30  *
  31  * Private definitions for atomic operations
  32  */
  33
  34 #ifndef LIBDRM_ATOMICS_H
  35 #define LIBDRM_ATOMICS_H
  36
  37 #if HAVE_LIBDRM_ATOMIC_PRIMITIVES
  38
  39 #define HAS_ATOMIC_OPS 1
  40
  41 typedef struct {
  42         int atomic;
  43 } atomic_t;
  44
  45 # define atomic_read(x) ((x)->atomic)
  46 # define atomic_set(x, val) ((x)->atomic = (val))
  47 # define atomic_inc(x) ((void) __sync_fetch_and_add (&(x)->atomic, 1))
  48 # define atomic_inc_return(x) (__sync_add_and_fetch (&(x)->atomic, 1))
  49 # define atomic_dec_and_test(x) (__sync_add_and_fetch (&(x)->atomic, -1) == 0)
  50 # define atomic_add(x, v) ((void) __sync_add_and_fetch(&(x)->atomic, (v)))
  51 # define atomic_dec(x, v) ((void) __sync_sub_and_fetch(&(x)->atomic, (v)))
  52 # define atomic_cmpxchg(x, oldv, newv) __sync_val_compare_and_swap (&(x)->atomic, oldv, newv)
  53
  54 #endif
  55
  56 #if HAVE_LIB_ATOMIC_OPS
  57 #define AO_REQUIRE_CAS
  58 #include <atomic_ops.h>
  59
  60 #define HAS_ATOMIC_OPS 1
  61
  62 typedef struct {
  63         AO_t atomic;
  64 } atomic_t;
  65
  66 # define atomic_read(x) AO_load_full(&(x)->atomic)
  67 # define atomic_set(x, val) AO_store_full(&(x)->atomic, (val))
  68 # define atomic_inc(x) ((void) AO_fetch_and_add1_full(&(x)->atomic))
  69 # define atomic_inc_return(x) (AO_fetch_and_add1_full(&(x)->atomic) + 1)
  70 # define atomic_add(x, v) ((void) AO_fetch_and_add_full(&(x)->atomic, (v)))
  71 # define atomic_dec(x, v) ((void) AO_fetch_and_add_full(&(x)->atomic, -(v)))
  72 # define atomic_dec_and_test(x) (AO_fetch_and_sub1_full(&(x)->atomic) == 1)
  73 # define atomic_cmpxchg(x, oldv, newv) AO_compare_and_swap_full(&(x)->atomic, oldv, newv)
  74
  75 #endif
  76
  77 #if (defined(__sun) || defined(__NetBSD__)) && !defined(HAS_ATOMIC_OPS)  /* Solaris & OpenSolaris & NetBSD */
  78
  79 #include <sys/atomic.h>
  80 #define HAS_ATOMIC_OPS 1
  81
  82 #if defined(__NetBSD__)
  83 #define LIBDRM_ATOMIC_TYPE int
  84 #else
  85 #define LIBDRM_ATOMIC_TYPE uint_t
  86 #endif
  87
  88 typedef struct { LIBDRM_ATOMIC_TYPE atomic; } atomic_t;
  89
  90 # define atomic_read(x) (int) ((x)->atomic)
  91 # define atomic_set(x, val) ((x)->atomic = (LIBDRM_ATOMIC_TYPE)(val))
  92 # define atomic_inc(x) (atomic_inc_uint (&(x)->atomic))
  93 # define atomic_inc_return(x) (atomic_inc_uint_nv(&(x)->atomic))
  94 # define atomic_dec_and_test(x) (atomic_dec_uint_nv(&(x)->atomic) == 0)
  95 # define atomic_add(x, v) (atomic_add_int(&(x)->atomic, (v)))
  96 # define atomic_dec(x, v) (atomic_add_int(&(x)->atomic, -(v)))
  97 # define atomic_cmpxchg(x, oldv, newv) atomic_cas_uint (&(x)->atomic, oldv, newv)
  98
  99 #endif
 100
 101 #if !defined(HAS_ATOMIC_OPS)
 102 #error libdrm requires atomic operations, please define them for your CPU/compiler.
 103 #endif
 104
 105 static inline int atomic_add_unless(atomic_t *v, int add, int unless)
 106 {
 107         int c, old;
 108         c = atomic_read(v);
 109         while (c != unless && (old = atomic_cmpxchg(v, c, c + add)) != c)
 110                 c = old;
 111         return c == unless;
 112 }
 113
 114 #endif