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diff --git a/pr/include/md/_linux.h b/pr/include/md/_linux.h
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--- a/pr/include/md/_linux.h
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+++ b/pr/include/md/_linux.h
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@@ -82,53 +82,73 @@
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 #define NO_DLOPEN_NULL
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 #endif
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 #if defined(__FreeBSD_kernel__) || defined(__GNU__)
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 #define _PR_HAVE_SOCKADDR_LEN
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 #endif
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 #if defined(__i386__)
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+#if defined(__GNUC__)
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+/* Use GCC built-in functions */
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+#define _PR_HAVE_ATOMIC_OPS
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+#define _MD_INIT_ATOMIC()
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+#define _MD_ATOMIC_INCREMENT(ptr) __sync_add_and_fetch(ptr, 1)
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+#define _MD_ATOMIC_DECREMENT(ptr) __sync_sub_and_fetch(ptr, 1)
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+#define _MD_ATOMIC_ADD(ptr, i) __sync_add_and_fetch(ptr, i)
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+#define _MD_ATOMIC_SET(ptr, nv) __sync_lock_test_and_set(ptr, nv)
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+#else
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 #define _PR_HAVE_ATOMIC_OPS
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 #define _MD_INIT_ATOMIC()
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 extern PRInt32 _PR_x86_AtomicIncrement(PRInt32 *val);
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 #define _MD_ATOMIC_INCREMENT          _PR_x86_AtomicIncrement
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 extern PRInt32 _PR_x86_AtomicDecrement(PRInt32 *val);
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 #define _MD_ATOMIC_DECREMENT          _PR_x86_AtomicDecrement
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 extern PRInt32 _PR_x86_AtomicAdd(PRInt32 *ptr, PRInt32 val);
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 #define _MD_ATOMIC_ADD                _PR_x86_AtomicAdd
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 extern PRInt32 _PR_x86_AtomicSet(PRInt32 *val, PRInt32 newval);
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 #define _MD_ATOMIC_SET                _PR_x86_AtomicSet
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 #endif
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+#endif
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 #if defined(__ia64__)
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 #define _PR_HAVE_ATOMIC_OPS
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 #define _MD_INIT_ATOMIC()
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 extern PRInt32 _PR_ia64_AtomicIncrement(PRInt32 *val);
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 #define _MD_ATOMIC_INCREMENT          _PR_ia64_AtomicIncrement
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 extern PRInt32 _PR_ia64_AtomicDecrement(PRInt32 *val);
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 #define _MD_ATOMIC_DECREMENT          _PR_ia64_AtomicDecrement
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 extern PRInt32 _PR_ia64_AtomicAdd(PRInt32 *ptr, PRInt32 val);
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 #define _MD_ATOMIC_ADD                _PR_ia64_AtomicAdd
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 extern PRInt32 _PR_ia64_AtomicSet(PRInt32 *val, PRInt32 newval);
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 #define _MD_ATOMIC_SET                _PR_ia64_AtomicSet
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 #endif
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 #if defined(__x86_64__)
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+#if defined(__GNUC__)
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+/* Use GCC built-in functions */
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+#define _PR_HAVE_ATOMIC_OPS
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+#define _MD_INIT_ATOMIC()
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+#define _MD_ATOMIC_INCREMENT(ptr) __sync_add_and_fetch(ptr, 1)
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+#define _MD_ATOMIC_DECREMENT(ptr) __sync_sub_and_fetch(ptr, 1)
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+#define _MD_ATOMIC_ADD(ptr, i) __sync_add_and_fetch(ptr, i)
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+#define _MD_ATOMIC_SET(ptr, nv) __sync_lock_test_and_set(ptr, nv)
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+#else
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 #define _PR_HAVE_ATOMIC_OPS
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 #define _MD_INIT_ATOMIC()
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 extern PRInt32 _PR_x86_64_AtomicIncrement(PRInt32 *val);
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 #define _MD_ATOMIC_INCREMENT          _PR_x86_64_AtomicIncrement
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 extern PRInt32 _PR_x86_64_AtomicDecrement(PRInt32 *val);
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 #define _MD_ATOMIC_DECREMENT          _PR_x86_64_AtomicDecrement
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 extern PRInt32 _PR_x86_64_AtomicAdd(PRInt32 *ptr, PRInt32 val);
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 #define _MD_ATOMIC_ADD                _PR_x86_64_AtomicAdd
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 extern PRInt32 _PR_x86_64_AtomicSet(PRInt32 *val, PRInt32 newval);
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 #define _MD_ATOMIC_SET                _PR_x86_64_AtomicSet
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 #endif
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+#endif
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 #if defined(__or1k__)
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 #if defined(__GNUC__)
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 /* Use GCC built-in functions */
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 #define _PR_HAVE_ATOMIC_OPS
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 #define _MD_INIT_ATOMIC()
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 #define _MD_ATOMIC_INCREMENT(ptr) __sync_add_and_fetch(ptr, 1)
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 #define _MD_ATOMIC_DECREMENT(ptr) __sync_sub_and_fetch(ptr, 1)