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, 61 insertions, 0 deletions

diff --git a/ldso/ldso/xtensa/resolve.S b/ldso/ldso/xtensa/resolve.S
new file mode 100644
index 000000000..fb298391c
--- /dev/null
+++ b/ldso/ldso/xtensa/resolve.S
@@ -0,0 +1,61 @@
+/* Xtensa dynamic resolver.
+   Parts copied from glibc/sysdeps/xtensa/dl-trampoline.S
+   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.  */
+
+#define MIN_FRAME_SIZE 32
+
+#ifdef __XTENSA_EB__
+#define XTENSA_IMM12_FLD_OFFSET 8
+#else /* __XTENSA_EL__ */
+#define XTENSA_IMM12_FLD_OFFSET 12
+#endif /* __XTENSA_EL__ */
+
+	.text
+	.align	4
+	.global	_dl_linux_resolve
+	.type	_dl_linux_resolve, @function
+_dl_linux_resolve:
+	/* Fix up the high 2 bits of the return address.  */
+	mov	a14, a0		// save a0 temporarily
+	_call0	0f
+	.align	4
+0:	extui	a13, a0, 30, 2
+	slli	a13, a13, 30
+	mov	a0, a14		// restore a0
+	slli	a12, a0, 2
+	srli	a12, a12, 2
+	or	a12, a12, a13
+
+	/* Call the fixup function.  */
+	movi	a8, _dl_linux_resolver
+	callx8	a8
+
+	/* Extract the target's frame size from the ENTRY instruction.  */
+	l32i	a11, a10, 0
+	extui	a11, a11, XTENSA_IMM12_FLD_OFFSET, 12
+	slli	a11, a11, 3
+
+	addi	a11, a11, -MIN_FRAME_SIZE
+	sub	a11, sp, a11
+	movsp	sp, a11
+
+	/* Jump to the next instruction past the ENTRY.  */
+	addi	a10, a10, 3
+	jx	a10
+	.size	_dl_linux_resolve, . - _dl_linux_resolve