--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/libavutil/atomic_gcc.h	Wed Nov 16 11:16:33 2016 +0200
@@ -0,0 +1,78 @@
+/*
+ * Copyright (c) 2012 Ronald S. Bultje <rsbultje@gmail.com>
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg 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.
+ *
+ * FFmpeg 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 FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#ifndef AVUTIL_ATOMIC_GCC_H
+#define AVUTIL_ATOMIC_GCC_H
+
+#include <stdint.h>
+
+#include "atomic.h"
+
+#define avpriv_atomic_int_get atomic_int_get_gcc
+static inline int atomic_int_get_gcc(volatile int *ptr)
+{
+#if HAVE_ATOMIC_COMPARE_EXCHANGE
+    return __atomic_load_n(ptr, __ATOMIC_SEQ_CST);
+#else
+    __sync_synchronize();
+    return *ptr;
+#endif
+}
+
+#define avpriv_atomic_int_set atomic_int_set_gcc
+static inline void atomic_int_set_gcc(volatile int *ptr, int val)
+{
+#if HAVE_ATOMIC_COMPARE_EXCHANGE
+    __atomic_store_n(ptr, val, __ATOMIC_SEQ_CST);
+#else
+    *ptr = val;
+    __sync_synchronize();
+#endif
+}
+
+#define avpriv_atomic_int_add_and_fetch atomic_int_add_and_fetch_gcc
+static inline int atomic_int_add_and_fetch_gcc(volatile int *ptr, int inc)
+{
+#if HAVE_ATOMIC_COMPARE_EXCHANGE
+    return __atomic_add_fetch(ptr, inc, __ATOMIC_SEQ_CST);
+#else
+    return __sync_add_and_fetch(ptr, inc);
+#endif
+}
+
+#define avpriv_atomic_ptr_cas atomic_ptr_cas_gcc
+static inline void *atomic_ptr_cas_gcc(void * volatile *ptr,
+                                       void *oldval, void *newval)
+{
+#if HAVE_SYNC_VAL_COMPARE_AND_SWAP
+#ifdef __ARMCC_VERSION
+    // armcc will throw an error if ptr is not an integer type
+    volatile uintptr_t *tmp = (volatile uintptr_t*)ptr;
+    return (void*)__sync_val_compare_and_swap(tmp, oldval, newval);
+#else
+    return __sync_val_compare_and_swap(ptr, oldval, newval);
+#endif
+#else
+    __atomic_compare_exchange_n(ptr, &oldval, newval, 0, __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST);
+    return oldval;
+#endif
+}
+
+#endif /* AVUTIL_ATOMIC_GCC_H */