diff options
Diffstat (limited to 'osdep/atomics.h')
-rw-r--r-- | osdep/atomics.h | 77 |
1 files changed, 77 insertions, 0 deletions
diff --git a/osdep/atomics.h b/osdep/atomics.h new file mode 100644 index 0000000000..e5fb717a78 --- /dev/null +++ b/osdep/atomics.h @@ -0,0 +1,77 @@ +/* + * This file is part of mpv. + * Copyright (c) 2013 Stefano Pigozzi <stefano.pigozzi@gmail.com> + * + * mpv is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * mpv 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 General Public License for more details. + * + * You should have received a copy of the GNU General Public License along + * with mpv. If not, see <http://www.gnu.org/licenses/>. + */ + +#ifndef MP_ATOMICS_H +#define MP_ATOMICS_H + +#include <inttypes.h> +#include "config.h" + +#define HAVE_ATOMICS 1 + +#if HAVE_STDATOMIC +#include <stdatomic.h> +#else + +// Emulate the parts of C11 stdatomic.h needed by mpv. +// Still relies on gcc/clang atomic builtins. + +typedef struct { volatile unsigned long v; } atomic_ulong; +typedef struct { volatile int v; } atomic_int; +typedef struct { volatile _Bool v; } atomic_bool; +typedef struct { volatile long long v; } atomic_llong; +typedef struct { volatile uint_least32_t v; } atomic_uint_least32_t; +typedef struct { volatile unsigned long long v; } atomic_ullong; + +#define ATOMIC_VAR_INIT(x) \ + {.v = (x)} + +#if HAVE_ATOMIC_BUILTINS + +#define atomic_load(p) \ + __atomic_load_n(&(p)->v, __ATOMIC_SEQ_CST) +#define atomic_store(p, val) \ + __atomic_store_n(&(p)->v, val, __ATOMIC_SEQ_CST) +#define atomic_fetch_add(a, b) \ + __atomic_fetch_add(&(a)->v, b, __ATOMIC_SEQ_CST) + +#elif HAVE_SYNC_BUILTINS + +#define atomic_load(p) \ + __sync_fetch_and_add(&(p)->v, 0) +#define atomic_store(p, val) \ + (__sync_synchronize(), (p)->v = (val), __sync_synchronize()) +#define atomic_fetch_add(a, b) \ + __sync_fetch_and_add(&(a)->v, b) + +#else + +// This is extremely wrong. The build system actually disables code that has +// a serious dependency on working atomics, so this is barely ok. +#define atomic_load(p) ((p)->v) +#define atomic_store(p, val) ((p)->v = (val)) +#define atomic_fetch_add(a, b) (((a)->v += (b)) - (b)) + +#undef HAVE_ATOMICS +#define HAVE_ATOMICS 0 + +#endif /* no atomics */ + +#endif /* else HAVE_STDATOMIC */ + +#endif |