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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 */