diff --git a/Makefile b/Makefile
index d82f0e25..89fbd162 100644
--- a/Makefile
+++ b/Makefile
@@ -55,6 +55,7 @@ C_FILES += rtemsbsd/src/rtems-bsd-taskqueue.c
 C_FILES += rtemsbsd/src/rtems-bsd-timesupport.c
 C_FILES += rtemsbsd/src/rtems-bsd-newproc.c
 C_FILES += rtemsbsd/src/rtems-bsd-vm_glue.c
+C_FILES += rtemsbsd/src/rtems-bsd-subr.c
 C_FILES += freebsd/kern/subr_eventhandler.c
 C_FILES += freebsd/kern/kern_subr.c
 C_FILES += freebsd/kern/kern_tc.c
diff --git a/freebsd-to-rtems.py b/freebsd-to-rtems.py
index ec63e829..a4032f88 100755
--- a/freebsd-to-rtems.py
+++ b/freebsd-to-rtems.py
@@ -548,6 +548,7 @@ rtems.addRTEMSSourceFiles(
 		'src/rtems-bsd-timesupport.c',
 		'src/rtems-bsd-newproc.c',
 		'src/rtems-bsd-vm_glue.c',
+		'src/rtems-bsd-subr.c',
 	]
 )
 rtems.addEmptyHeaderFiles(
diff --git a/rtemsbsd/src/rtems-bsd-subr.c b/rtemsbsd/src/rtems-bsd-subr.c
new file mode 100644
index 00000000..0a7c4296
--- /dev/null
+++ b/rtemsbsd/src/rtems-bsd-subr.c
@@ -0,0 +1,79 @@
+/**
+ * @file
+ *
+ * @ingroup rtems_bsd_rtems
+ *
+ * @brief TODO.
+ */
+
+/*
+ * This file contains rtems versions of methods defined in kern_subr.c
+ * Methods that do not require modification will remain in the original
+ * file.  
+ *
+ * Copyright (c) 1982, 1986, 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ * (c) UNIX System Laboratories, Inc.
+ * All or some portions of this file are derived from material licensed
+ * to the University of California by American Telephone and Telegraph
+ * Co. or Unix System Laboratories, Inc. and are reproduced herein with
+ * the permission of UNIX System Laboratories, Inc.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)kern_subr.c	8.3 (Berkeley) 1/21/94
+ *
+ *
+ *  COPYRIGHT (c) 2012.
+ *  On-Line Applications Research Corporation (OAR).
+ *
+ *  The license and distribution terms for this file may be
+ *  found in the file LICENSE in this distribution or at
+ *  http://www.rtems.com/license/LICENSE.
+ */
+
+#include <freebsd/machine/rtems-bsd-config.h>
+
+#include <freebsd/sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <freebsd/local/opt_zero.h>
+
+#include <freebsd/sys/param.h>
+#include <freebsd/sys/systm.h>
+#include <freebsd/sys/kernel.h>
+#include <freebsd/sys/ktr.h>
+#include <freebsd/sys/limits.h>
+#include <freebsd/sys/lock.h>
+#include <freebsd/sys/mutex.h>
+#include <rtems.h>
+
+void
+uio_yield(void)
+{
+  DROP_GIANT();
+  rtems_task_wake_after( RTEMS_YIELD_PROCESSOR );
+  PICKUP_GIANT();
+}