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-rw-r--r--sysdeps/mips/sys/asm.h19
1 files changed, 18 insertions, 1 deletions
diff --git a/sysdeps/mips/sys/asm.h b/sysdeps/mips/sys/asm.h
index b04c36ba5e..b590802fd9 100644
--- a/sysdeps/mips/sys/asm.h
+++ b/sysdeps/mips/sys/asm.h
@@ -1,4 +1,5 @@
-/* Copyright (C) 1997, 1998, 2002, 2003, 2004 Free Software Foundation, Inc.
+/* Copyright (C) 1997, 1998, 2002, 2003, 2004, 2005
+   Free Software Foundation, Inc.
    This file is part of the GNU C Library.
    Contributed by Ralf Baechle <ralf@gnu.org>.
 
@@ -470,4 +471,20 @@ symbol		=	value
 # define MTC0	dmtc0
 #endif
 
+/* The MIPS archtectures do not have a uniform memory model.  Particular
+   platforms may provide additional guarantees - for instance, the R4000
+   LL and SC instructions implicitly perform a SYNC, and the 4K promises
+   strong ordering.
+
+   However, in the absence of those guarantees, we must assume weak ordering
+   and SYNC explicitly where necessary.
+
+   Some obsolete MIPS processors may not support the SYNC instruction.  This
+   applies to "true" MIPS I processors; most of the processors which compile
+   using MIPS I implement parts of MIPS II.  */
+
+#ifndef MIPS_SYNC
+# define MIPS_SYNC	sync
+#endif
+
 #endif /* sys/asm.h */