Chris Zankel writes:

The following patches add support for the Xtensa processor architecture
to uClibc. They are based on a recent SVN checkout (12/05/2007).

The first patch (attached to this post) adds Xtensa support to various
shared configuration and make files. The following patches then include
the Xtensa specific files and directories.

I welcome any feedback and would appreciate it if you could include the
patches into the mainline tree. I am certainly committed to maintain the port. 

Bob Wilson was kind enough to review the patches.

Some notes about the architecture: Xtensa is a configurable and
extensible processor architecture developed by Tensilica. For more
information, please visit: www.linux-xtensa.org.

1 files changed, 48 insertions, 0 deletions

diff --git a/libpthread/linuxthreads.old/sysdeps/xtensa/pt-machine.h b/libpthread/linuxthreads.old/sysdeps/xtensa/pt-machine.h
new file mode 100644
index 000000000..d5ab9f0ec
--- /dev/null
+++ b/libpthread/linuxthreads.old/sysdeps/xtensa/pt-machine.h
@@ -0,0 +1,48 @@
+/* Machine-dependent pthreads configuration and inline functions.
+   Xtensa version.
+
+   Copyright (C) 2007 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library 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.
+
+   The GNU C Library 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 the GNU C Library; if not, write to the Free
+   Software Foundation, Inc., 51 Franklin Street - Fifth Floor,
+   Boston, MA 02110-1301, USA.  */
+
+#ifndef _PT_MACHINE_H
+#define _PT_MACHINE_H   1
+
+#include <sys/syscall.h>
+#include <asm/unistd.h>
+
+#ifndef PT_EI
+# define PT_EI extern inline
+#endif
+
+/* Memory barrier.  */
+#define MEMORY_BARRIER() __asm__ ("memw" : : : "memory")
+
+/* Spinlock implementation; required.  */
+PT_EI long int
+testandset (int *spinlock)
+{
+  int unused = 0;
+  return INTERNAL_SYSCALL (xtensa, , 4, SYS_XTENSA_ATOMIC_SET,
+			   spinlock, 1, unused);
+}
+
+/* Get some notion of the current stack.  Need not be exactly the top
+   of the stack, just something somewhere in the current frame.  */
+#define CURRENT_STACK_FRAME __builtin_frame_address (0)
+
+#endif /* _PT_MACHINE_H */