diff --git a/arch/sim/src/host.h b/arch/sim/src/host.h
new file mode 100644
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+++ b/arch/sim/src/host.h
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+/**************************************************************************
+ * arch/sim/src/host.h
+ *
+ *   Copyright (C) 2014 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <gnutt@nuttx.org>
+ *
+ * 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.
+ * 3. Neither the name NuttX 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 COPYRIGHT HOLDERS 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
+ * COPYRIGHT OWNER 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.
+ *
+ **************************************************************************/
+
+#ifndef __ARCH_SIM_SRC_HOST_H
+#define __ARCH_SIM_SRC_HOST_H
+
+/**************************************************************************
+ * Included Files
+ **************************************************************************/
+
+/**************************************************************************
+ * Pre-processor Definitions
+ **************************************************************************/
+
+/**************************************************************************
+ * Public Types
+ **************************************************************************/
+
+/**************************************************************************
+ * Public Variables
+ **************************************************************************/
+
+#ifndef __ASSEMBLY__
+
+/**************************************************************************
+ * Public Function Prototypes
+ **************************************************************************/
+
+/* up_uartwait.c **********************************************************/
+/* Exported to Nuttx domain files to host domain files */
+
+void simuart_initialize(void);
+void simuart_post(void);
+void simuart_wait(void);
+
+#endif /* __ASSEMBLY__ */
+#endif /* __ARCH_SIM_SRC_HOST_H */