1 files changed, 83 insertions, 0 deletions
diff --git a/libjava/sysdep/x86-64/locks.h b/libjava/sysdep/x86-64/locks.h
new file mode 100644
index 000000000..fdc0a3efb
--- /dev/null
+++ b/libjava/sysdep/x86-64/locks.h
@@ -0,0 +1,83 @@
+/* locks.h - Thread synchronization primitives. X86/x86-64 implementation.
+
+   Copyright (C) 2002  Free Software Foundation
+
+   Contributed by Bo Thorsen <bo@suse.de>.
+
+   This file is part of libgcj.
+
+This software is copyrighted work licensed under the terms of the
+Libgcj License.  Please consult the file "LIBGCJ_LICENSE" for
+details.  */
+
+#ifndef __SYSDEP_LOCKS_H__
+#define __SYSDEP_LOCKS_H__
+
+typedef size_t obj_addr_t;	/* Integer type big enough for object	*/
+				/* address.				*/
+
+// Atomically replace *addr by new_val if it was initially equal to old.
+// Return true if the comparison succeeded.
+// Assumed to have acquire semantics, i.e. later memory operations
+// cannot execute before the compare_and_swap finishes.
+inline static bool
+compare_and_swap(volatile obj_addr_t *addr,
+		 obj_addr_t old,
+		 obj_addr_t new_val)
+{
+  char result;
+#ifdef __x86_64__
+  __asm__ __volatile__("lock; cmpxchgq %2, %0; setz %1"
+	      : "=m"(*(addr)), "=q"(result)
+	      : "r" (new_val), "a"(old), "m"(*addr)
+	      : "memory");
+#else
+  __asm__ __volatile__("lock; cmpxchgl %2, %0; setz %1"
+		       : "=m"(*addr), "=q"(result)
+		       : "r" (new_val), "a"(old), "m"(*addr)
+		       : "memory");
+#endif
+  return (bool) result;
+}
+
+// Set *addr to new_val with release semantics, i.e. making sure
+// that prior loads and stores complete before this
+// assignment.
+// On X86/x86-64, the hardware shouldn't reorder reads and writes,
+// so we just have to convince gcc not to do it either.
+inline static void
+release_set(volatile obj_addr_t *addr, obj_addr_t new_val)
+{
+  __asm__ __volatile__(" " : : : "memory");
+  *(addr) = new_val;
+}
+
+// Compare_and_swap with release semantics instead of acquire semantics.
+// On many architecture, the operation makes both guarantees, so the
+// implementation can be the same.
+inline static bool
+compare_and_swap_release(volatile obj_addr_t *addr,
+			 obj_addr_t old,
+			 obj_addr_t new_val)
+{
+  return compare_and_swap(addr, old, new_val);
+}
+
+// Ensure that subsequent instructions do not execute on stale
+// data that was loaded from memory before the barrier.
+// On X86/x86-64, the hardware ensures that reads are properly ordered.
+inline static void
+read_barrier()
+{
+}
+
+// Ensure that prior stores to memory are completed with respect to other
+// processors.
+inline static void
+write_barrier()
+{
+  /* x86-64/X86 does not reorder writes. We just need to ensure that
+     gcc also doesn't.  */
+  __asm__ __volatile__(" " : : : "memory");
+}
+#endif