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, 46 insertions, 0 deletions

diff --git a/libc/sysdeps/linux/xtensa/bits/setjmp.h b/libc/sysdeps/linux/xtensa/bits/setjmp.h
new file mode 100644
index 000000000..1bc4896c8
--- /dev/null
+++ b/libc/sysdeps/linux/xtensa/bits/setjmp.h
@@ -0,0 +1,46 @@
+/* Copyright (C) 1997, 1998, 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.  */
+
+/* Define the machine-dependent type `jmp_buf'.  Xtensa version.  */
+#ifndef _BITS_SETJMP_H
+#define _BITS_SETJMP_H	1
+
+#if !defined _SETJMP_H && !defined _PTHREAD_H
+# error "Never include <bits/setjmp.h> directly; use <setjmp.h> instead."
+#endif
+
+/* The jmp_buf structure for Xtensa holds the following (where "proc"
+   is the procedure that calls setjmp): 4-12 registers from the window
+   of proc, the 4 words from the save area at proc's $sp (in case a
+   subsequent alloca in proc moves $sp), and the return address within
+   proc.  Everything else is saved on the stack in the normal save areas.  */
+
+#ifndef	_ASM
+typedef int __jmp_buf[17];
+#endif
+
+#define JB_SP	1
+#define JB_PC	16
+
+/* Test if longjmp to JMPBUF would unwind the frame containing a local
+   variable at ADDRESS.  */
+
+#define _JMPBUF_UNWINDS(jmpbuf, address) \
+  ((void *) (address) < (void *) (jmpbuf)[JB_SP])
+
+#endif	/* bits/setjmp.h */