NuttX RTOS

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@3 42af7a65-404d-4744-a932-0658087f49c3

25 files changed, 2553 insertions, 0 deletions

diff --git a/nuttx/arch/sim/Make.defs b/nuttx/arch/sim/Make.defs
new file mode 100644
index 000000000..12e288a57
--- /dev/null
+++ b/nuttx/arch/sim/Make.defs
@@ -0,0 +1,69 @@
+############################################################
+# Make.defs
+#
+#   Copyright (C) 2007 Gregory Nutt. All rights reserved.
+#   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+#
+# 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 Gregory Nutt 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.
+#
+############################################################
+
+include ${TOPDIR}/.config
+
+ifeq ("${CONFIG_DEBUG}","y")
+  ARCHOPTIMIZATION	= -g
+else
+  ARCHOPTIMIZATION	= -O2
+endif
+
+ARCHCPUFLAGS		= 
+ARCHPICFLAGS		= -fpic
+ARCHWARNINGS		= -Wall -Wstrict-prototypes -Wshadow
+ARCHDEFINES		=
+ARCHINCLUDES		= -I. -isystem $(TOPDIR)/include
+ARCHSCRIPT		=
+
+CROSSDEV		=
+CC			= $(CROSSDEV)gcc
+LD			= $(CROSSDEV)ld
+AR			= $(CROSSDEV)ar
+NM			= $(CROSSDEV)nm
+OBJCOPY			= $(CROSSDEV)objcopy
+OBJDUMP			= $(CROSSDEV)objdump
+
+CFLAGS			= $(ARCHWARNINGS) $(ARCHOPTIMIZATION) \
+			  $(ARCHCPUFLAGS) $(ARCHINCLUDES) $(ARCHDEFINES) -pipe
+
+LDFLAGS			= $(ARCHSCRIPT)
+EXTRA_LIBS		= -lc
+
+ifeq ("${CONFIG_DEBUG}","y")
+  LDFLAGS		+= -g
+endif
+
+
diff --git a/nuttx/arch/sim/defconfig b/nuttx/arch/sim/defconfig
new file mode 100644
index 000000000..60656fce3
--- /dev/null
+++ b/nuttx/arch/sim/defconfig
@@ -0,0 +1,154 @@
+############################################################
+# defconfig
+#
+#   Copyright (C) 2007 Gregory Nutt. All rights reserved.
+#   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+#
+# 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 Gregory Nutt 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.
+#
+############################################################
+#
+# architecture selection
+#
+# CONFIG_ARCH - identifies the arch subdirectory
+# CONFIG_ARCH_name - for use in C code
+#
+CONFIG_ARCH=sim
+CONFIG_ARCH_SIM=y
+
+#
+# General OS setup
+#
+# CONFIG_EXAMPLE - identifies the subdirectgory in examples
+#   that will be used in the build
+# CONFIG_DEBUG - enables built-in debug options
+# CONFIG_DEBUG_VERBOSE - enables verbose debug output
+# CONFIG_HAVE_LOWPUTC - architecture supports low-level, boot
+#   time console output
+# CONFIG_RR_INTERVAL - The round robin timeslice will be set
+#   this number of milliseconds;  Round robin scheduling can
+#   be disabled by setting this value to zero.
+# CONFIG_SCHED_INSTRUMENTATION - enables instrumentation in 
+#   scheduler to monitor system performance
+# CONFIG_TASK_NAME_SIZE - Spcifies that maximum size of a
+#   task name to save in the TCB.  Useful if scheduler
+#   instrumentation is selected.  Set to zero to disable.
+# CONFIG_JULIAN_TIME - Enables Julian time conversions
+# CONFIG_START_YEAR, CONFIG_START_MONTH, CONFIG_START_DAY -
+#   Used to initialize the internal time logic.
+# CONFIG_DEV_CONSOLE - Set if architecture-specific logic
+#   provides /dev/console.  Enables stdout, stderr, stdin.
+#
+CONFIG_EXAMPLE=ostest
+CONFIG_DEBUG=y
+CONFIG_DEBUG_VERBOSE=y
+CONFIG_ARCH_LOWPUTC=y
+CONFIG_RR_INTERVAL=200
+CONFIG_SCHED_INSTRUMENTATION=n
+CONFIG_TASK_NAME_SIZE=32
+CONFIG_START_YEAR=2007
+CONFIG_START_MONTH=2
+CONFIG_START_DAY=13
+CONFIG_JULIAN_TIME=n
+CONFIG_DEV_CONSOLE=y
+
+#
+# Allow for artchitecture optimized implementations
+#
+# The architecture can provide optimized versions of the
+# following to improve sysem performance
+#
+CONFIG_ARCH_MEMCPY=n
+CONFIG_ARCH_MEMCMP=n
+CONFIG_ARCH_MEMMOVE=n
+CONFIG_ARCH_MEMSET=n
+CONFIG_ARCH_STRCMP=n
+CONFIG_ARCH_STRCPY=n
+CONFIG_ARCH_STRNCPY=n
+CONFIG_ARCH_STRLEN=n
+CONFIG_ARCH_BZERO=n
+CONFIG_ARCH_KMALLOC=n
+CONFIG_ARCH_KZMALLOC=n
+CONFIG_ARCH_KFREE=n
+
+# General Compile environment setup
+#
+# CONFIG_HAVE_LONG_LONG - enable if your architecture supports
+#   long long types and if you plan to use them
+CONFIG_HAVE_LONG_LONG=n
+
+#
+# Sizes of configurable things (0 disables)
+#
+# CONFIG_NPTHREAD_KEYS - The number of items of thread-
+#   specific data that can be retained
+# CONFIG_NFILE_DESCRIPTORS - The maximum number of file
+#   descriptors (one for each open)
+# CONFIG_NFILE_STREAMS - The maximum number of streams that
+#   can be fopen'ed
+# CONFIG_STDIO_BUFFER_SIZE - Size of the buffer to allocate
+#   on fopen. (Only if CONFIG_NFILE_STREAMS > 0)
+# CONFIG_NUNGET_CHARS - Number of characters that can be
+#   buffered by ungetc() (Only if CONFIG_NFILE_STREAMS > 0)
+# CONFIG_PREALLOC_MQ_MSGS - The number of pre-allocated message
+#   structures.  The system manages a pool of preallocated
+#   message structures to minimize dynamic allocations
+# CONFIG_MQ_MAXMSGSIZE - Message structures are allocated with
+#   a fixed payload size given by this settin (does not include
+#   other message structure overhead.
+# CONFIG_PREALLOC_WDOGS - The number of pre-allocated watchdog
+#   structures.  The system manages a pool of preallocated
+#   watchdog structures to minimize dynamic allocations
+#
+CONFIG_NPTHREAD_KEYS=4
+CONFIG_NFILE_DESCRIPTORS=32
+CONFIG_NFILE_STREAMS=16
+CONFIG_STDIO_BUFFER_SIZE=1024
+CONFIG_NUNGET_CHARS=2
+CONFIG_PREALLOC_MQ_MSGS=32
+CONFIG_MQ_MAXMSGSIZE=32
+CONFIG_PREALLOC_WDOGS=32
+
+#
+# Stack and heap information
+#
+# CONFIG_BOOT_FROM_FLASH - Some configurations support XIP
+#   operation from FLASH.
+# CONFIG_STACK_POINTER - The initial stack pointer
+# CONFIG_PROC_STACK_SIZE - The size of the initial stack
+# CONFIG_PTHREAD_STACK_MIN - Minimum pthread stack size
+# CONFIG_PTHREAD_STACK_DEFAULT - Default pthread stack size
+# CONFIG_HEAP_BASE - The beginning of the heap
+# CONFIG_HEAP_SIZE - The size of the heap
+#
+CONFIG_BOOT_FROM_FLASH=n
+CONFIG_PROC_STACK_SIZE=0x00001000
+CONFIG_PTHREAD_STACK_MIN=256
+CONFIG_PTHREAD_STACK_DEFAULT=8192
+CONFIG_HEAP_BASE=
+CONFIG_HEAP_SIZE=
diff --git a/nuttx/arch/sim/include/arch.h b/nuttx/arch/sim/include/arch.h
new file mode 100644
index 000000000..32eadcd17
--- /dev/null
+++ b/nuttx/arch/sim/include/arch.h
@@ -0,0 +1,80 @@
+/************************************************************
+ * arch.h
+ *
+ *   Copyright (C) 2007 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * 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 Gregory Nutt 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.
+ *
+ ************************************************************/
+
+/* This file should never be included directed but, rather,
+ * only indirectly through nuttx/arch.h
+ */
+
+#ifndef __ARCH_ARCH_H
+#define __ARCH_ARCH_H
+
+/************************************************************
+ * Included Files
+ ************************************************************/
+
+/************************************************************
+ * Definitions
+ ************************************************************/
+
+/************************************************************
+ * Inline functions
+ ************************************************************/
+
+/************************************************************
+ * Public Types
+ ************************************************************/
+
+/************************************************************
+ * Public Variables
+ ************************************************************/
+
+/************************************************************
+ * Public Function Prototypes
+ ************************************************************/
+
+#ifdef __cplusplus
+#define EXTERN extern "C"
+extern "C" {
+#else
+#define EXTERN extern
+#endif
+
+#undef EXTERN
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* __ARCH_ARCH_H */
+
diff --git a/nuttx/arch/sim/include/irq.h b/nuttx/arch/sim/include/irq.h
new file mode 100644
index 000000000..3ae46aa42
--- /dev/null
+++ b/nuttx/arch/sim/include/irq.h
@@ -0,0 +1,106 @@
+/************************************************************
+ * irq.h
+ *
+ *   Copyright (C) 2007 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * 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 Gregory Nutt 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.
+ *
+ ************************************************************/
+
+/* This file should never be included directed but, rather,
+ * only indirectly through nuttx/irq.h
+ */
+
+#ifndef __ARCH_IRQ_H
+#define __ARCH_IRQ_H
+
+/************************************************************
+ * Included Files
+ ************************************************************/
+
+/************************************************************
+ * Definitions
+ ************************************************************/
+
+#define NR_IRQS 0
+
+/************************************************************
+ * Public Types
+ ************************************************************/
+
+/* This struct defines the way the registers are stored */
+
+#ifndef __ASSEMBLY__
+struct xcptcontext
+{
+   void *sigdeliver; /* Actual type is sig_deliver_t */
+
+   /* Storage order: %ebx, $esi, %edi, %ebp, sp, and return PC */
+
+   int regs[6];
+};
+#endif
+
+/************************************************************
+ * Inline functions
+ ************************************************************/
+
+#ifndef __ASSEMBLY__
+static inline uint32 irqsave(void)
+{
+  return 0;
+}
+
+static inline void irqrestore(uint32 flags)
+{
+}
+#endif
+
+/************************************************************
+ * Public Variables
+ ************************************************************/
+
+/************************************************************
+ * Public Function Prototypes
+ ************************************************************/
+
+#ifdef __cplusplus
+#define EXTERN extern "C"
+extern "C" {
+#else
+#define EXTERN extern
+#endif
+
+#undef EXTERN
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* __ARCH_IRQ_H */
+
diff --git a/nuttx/arch/sim/include/types.h b/nuttx/arch/sim/include/types.h
new file mode 100644
index 000000000..39232af7d
--- /dev/null
+++ b/nuttx/arch/sim/include/types.h
@@ -0,0 +1,70 @@
+/************************************************************
+ * types.h
+ *
+ *   Copyright (C) 2007 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * 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 Gregory Nutt 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.
+ *
+ ************************************************************/
+
+/* This file should never be included directed but, rather,
+ * only indirectly through sys/types.h
+ */
+
+#ifndef __ARCH_TYPES_H
+#define __ARCH_TYPES_H
+
+/************************************************************
+ * Included Files
+ ************************************************************/
+
+/************************************************************
+ * Definitions
+ ************************************************************/
+
+/************************************************************
+ * Type Declarations
+ ************************************************************/
+
+typedef char sbyte;
+typedef unsigned char ubyte;
+typedef unsigned char uint8;
+typedef unsigned char boolean;
+typedef short sint16;
+typedef unsigned short uint16;
+typedef int sint32;
+typedef unsigned int uint32;
+typedef long long sint64;
+typedef unsigned long long uint64;
+
+/************************************************************
+ * Global Function Prototypes
+ ************************************************************/
+
+#endif /* __ARCH_TYPES_H */
diff --git a/nuttx/arch/sim/setenv.sh b/nuttx/arch/sim/setenv.sh
new file mode 100755
index 000000000..d0a05bfdf
--- /dev/null
+++ b/nuttx/arch/sim/setenv.sh
@@ -0,0 +1,45 @@
+#!/bin/sh
+# setenv.sh
+#
+#   Copyright (C) 2007 Gregory Nutt. All rights reserved.
+#   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+#
+# 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 Gregory Nutt 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.
+#
+
+if [ "$(basename $0)" = "setenv" ] ; then
+  echo "You must source this script, not run it!" 1>&2
+  exit 1
+fi
+
+if [ -z ${PATH_ORIG} ]; then export PATH_ORIG=${PATH}; fi
+
+#export NUTTX_BIN=
+#export PATH=${NUTTX_BIN}:/sbin:/usr/sbin:${PATH_ORIG}
+
+echo "PATH : ${PATH}"
diff --git a/nuttx/arch/sim/src/Makefile b/nuttx/arch/sim/src/Makefile
new file mode 100644
index 000000000..780cff596
--- /dev/null
+++ b/nuttx/arch/sim/src/Makefile
@@ -0,0 +1,76 @@
+############################################################
+# Makefile
+#
+#   Copyright (C) 2007 Gregory Nutt. All rights reserved.
+#   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+#
+# 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 Gregory Nutt 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.
+#
+############################################################
+
+-include $(TOPDIR)/Make.defs
+
+MKDEP 	= $(TOPDIR)/tools/mkdeps.sh
+CFLAGS	+= -I$(TOPDIR)/sched
+
+ASRCS	= up_setjmp.S
+AOBJS	= $(ASRCS:.S=.o)
+CSRCS	= up_initialize.c up_idle.c up_interruptcontext.c up_initialstate.c \
+	  up_createstack.c up_usestack.c up_releasestack.c \
+	  up_unblocktask.c up_blocktask.c up_releasepending.c up_reprioritizertr.c \
+	  up_exit.c up_schedulesigaction.c up_allocateheap.c up_devconsole.c
+COBJS	= $(CSRCS:.c=.o)
+
+SRCS	= $(ASRCS) $(CSRCS)
+OBJS	= $(AOBJS) $(COBJS)
+
+all: up_head.o libarch.a
+
+$(AOBJS): %.o: %.S
+	$(CC) -c $(CFLAGS) -D__ASSEMBLY__ $< -o $@
+
+$(COBJS) up_head.o: %.o: %.c
+	$(CC) -c $(CFLAGS) $< -o $@
+
+libarch.a: $(OBJS)
+	$(AR) rcs $@ $(OBJS)
+
+.depend: Makefile $(SRCS)
+	$(MKDEP) $(CC) -- $(CFLAGS) -- $(SRCS) >Make.dep
+	touch $@
+
+depend: .depend
+
+clean:
+	rm -f libarch.a *.o *~
+
+distclean: clean
+	rm -f Make.dep .depend
+
+
+-include Make.dep
diff --git a/nuttx/arch/sim/src/up_allocateheap.c b/nuttx/arch/sim/src/up_allocateheap.c
new file mode 100644
index 000000000..b464719d4
--- /dev/null
+++ b/nuttx/arch/sim/src/up_allocateheap.c
@@ -0,0 +1,81 @@
+/************************************************************
+ * up_allocateheap.c
+ *
+ *   Copyright (C) 2007 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * 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 Gregory Nutt 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.
+ *
+ ************************************************************/
+
+/************************************************************
+ * Included Files
+ ************************************************************/
+
+#include <nuttx/config.h>
+#include <sys/types.h>
+#include <sched.h>
+#include <debug.h>
+#include <nuttx/arch.h>
+#include "os_internal.h"
+#include "up_internal.h"
+
+/************************************************************
+ * Private Definitions
+ ************************************************************/
+
+/************************************************************
+ * Private Data
+ ************************************************************/
+
+static ubyte sim_heap[SIM_HEAP_SIZE];
+
+/************************************************************
+ * Private Funtions
+ ************************************************************/
+
+/************************************************************
+ * Public Funtions
+ ************************************************************/
+
+/************************************************************
+ * Name: up_allocate_heap
+ *
+ * Description:
+ *   The heap may be statically allocated by
+ *   defining CONFIG_HEAP_BASE and CONFIG_HEAP_SIZE.  If these
+ *   are not defined, then this function will be called to
+ *   dynamically set aside the heap region.
+ *
+ ************************************************************/
+
+void up_allocate_heap(void **heap_start, size_t *heap_size)
+{
+  *heap_start = sim_heap;
+  *heap_size = SIM_HEAP_SIZE;
+}
diff --git a/nuttx/arch/sim/src/up_blocktask.c b/nuttx/arch/sim/src/up_blocktask.c
new file mode 100644
index 000000000..66cd89372
--- /dev/null
+++ b/nuttx/arch/sim/src/up_blocktask.c
@@ -0,0 +1,157 @@
+/************************************************************
+ * up_blocktask.c
+ *
+ *   Copyright (C) 2007 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * 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 Gregory Nutt 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.
+ *
+ ************************************************************/
+
+/************************************************************
+ * Included Files
+ ************************************************************/
+
+#include <nuttx/config.h>
+#include <sys/types.h>
+#include <sched.h>
+#include <debug.h>
+#include <nuttx/arch.h>
+#include "os_internal.h"
+#include "up_internal.h"
+
+/************************************************************
+ * Private Definitions
+ ************************************************************/
+
+/************************************************************
+ * Private Data
+ ************************************************************/
+
+/************************************************************
+ * Private Funtions
+ ************************************************************/
+
+/************************************************************
+ * Public Funtions
+ ************************************************************/
+
+/************************************************************
+ * Name: up_block_task
+ *
+ * Description:
+ *   The currently executing task at the head of
+ *   the ready to run list must be stopped.  Save its context
+ *   and move it to the inactive list specified by task_state.
+ *
+ * Inputs:
+ *   tcb: Refers to a task in the ready-to-run list (normally
+ *     the task at the the head of the list).  It most be
+ *     stopped, its context saved and moved into one of the
+ *     waiting task lists.  It it was the task at the head
+ *     of the ready-to-run list, then a context to the new
+ *     ready to run task must be performed.
+ *   task_state: Specifies which waiting task list should be
+ *     hold the blocked task TCB.
+ *
+ ************************************************************/
+
+void up_block_task(_TCB *tcb, tstate_t task_state)
+{
+  /* Verify that the context switch can be performed */
+  if ((tcb->task_state < FIRST_READY_TO_RUN_STATE) ||
+      (tcb->task_state > LAST_READY_TO_RUN_STATE))
+    {
+      PANIC(OSERR_BADBLOCKSTATE);
+    }
+  else
+    {
+      _TCB *rtcb = (_TCB*)g_readytorun.head;
+      boolean switch_needed;
+
+      dbg("Blocking TCB=%p\n", tcb);
+
+      /* Remove the tcb task from the ready-to-run list.  If we
+       * are blocking the task at the head of the task list (the
+       * most likely case), then a context switch to the next
+       * ready-to-run task is needed. In this case, it should
+       * also be true that rtcb == tcb.
+       */
+
+      switch_needed = sched_removereadytorun(tcb);
+
+      /* Add the task to the specified blocked task list */
+
+      sched_addblocked(tcb, (tstate_t)task_state);
+
+      /* If there are any pending tasks, then add them to the g_readytorun
+       * task list now
+       */
+
+      if (g_pendingtasks.head)
+        {
+          switch_needed |= sched_mergepending();
+        }
+
+      /* Now, perform the context switch if one is needed */
+
+      if (switch_needed)
+        {
+          /* Copy the exception context into the TCB at the (old) head of the
+          * g_readytorun Task list. if up_setjmp returns a non-zero
+           * value, then this is really the previously running task restarting!
+           */
+
+          if (!up_setjmp(rtcb->xcp.regs))
+            {
+              /* Restore the exception context of the rtcb at the (new) head 
+               * of the g_readytorun task list.
+               */
+
+              rtcb = (_TCB*)g_readytorun.head;
+              dbg("New Active Task TCB=%p\n", rtcb);
+
+              /* The way that we handle signals in the simulation is kind of
+               * a kludge.  This would be unsafe in a truly multi-threaded, interrupt
+               * driven environment.
+               */
+
+              if (rtcb->xcp.sigdeliver)
+                {
+                  dbg("Delivering signals TCB=%p\n", rtcb);
+                  ((sig_deliver_t)rtcb->xcp.sigdeliver)(rtcb);
+                  rtcb->xcp.sigdeliver = NULL;
+                }
+
+              /* Then switch contexts */
+
+              up_longjmp(rtcb->xcp.regs, 1);
+            }
+        }
+    }
+}
diff --git a/nuttx/arch/sim/src/up_createstack.c b/nuttx/arch/sim/src/up_createstack.c
new file mode 100644
index 000000000..0e2c63e4d
--- /dev/null
+++ b/nuttx/arch/sim/src/up_createstack.c
@@ -0,0 +1,109 @@
+/************************************************************
+ * up_createstack.c
+ *
+ *   Copyright (C) 2007 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * 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 Gregory Nutt 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.
+ *
+ ************************************************************/
+
+/************************************************************
+ * Included Files
+ ************************************************************/
+
+#include <nuttx/config.h>
+#include <sys/types.h>
+#include <nuttx/arch.h>
+#include <nuttx/kmalloc.h>
+#include "up_internal.h"
+
+/************************************************************
+ * Private Definitions
+ ************************************************************/
+
+/************************************************************
+ * Private Data
+ ************************************************************/
+
+/************************************************************
+ * Private Funtions
+ ************************************************************/
+
+/************************************************************
+ * Public Funtions
+ ************************************************************/
+
+/************************************************************
+ * Name: up_create_stack
+ *
+ * Description:
+ *   Allocate a stack for a new thread and setup
+ *   up stack-related information in the TCB.
+ *
+ *   The following TCB fields must be initialized:
+ *   adj_stack_size: Stack size after adjustment for hardware,
+ *     processor, etc.  This value is retained only for debug
+ *     purposes.
+ *   stack_alloc_ptr: Pointer to allocated stack
+ *   adj_stack_ptr: Adjusted StatckAllocPtr for HW.  The
+ *     initial value of the stack pointer.
+ *
+ * Inputs:
+ *   tcb: The TCB of new task
+ *   stack_size: The requested stack size.  At least this much
+ *     must be allocated.
+ *
+ ************************************************************/
+
+STATUS up_create_stack(_TCB *tcb, uint32 stack_size)
+{
+  STATUS ret = ERROR;
+
+  /* Move up to next even word boundary if necessary */
+
+  uint32 adj_stack_size = (stack_size + 3) & ~3;
+  uint32 adj_stack_words = adj_stack_size >> 2;
+
+  /* Allocate the memory for the stack */
+
+  uint32 *stack_alloc_ptr = (uint32*)kmalloc(adj_stack_size);
+  if (stack_alloc_ptr)
+    {
+      /* This is the address of the last word in the allocation */
+
+      uint32 *adj_stack_ptr = &stack_alloc_ptr[adj_stack_words - 1];
+
+      /* Save the values in the TCB */
+      tcb->adj_stack_size  = adj_stack_size;
+      tcb->stack_alloc_ptr = stack_alloc_ptr;
+      tcb->adj_stack_ptr   = adj_stack_ptr;
+      ret = OK;
+    }
+  return ret;
+}
diff --git a/nuttx/arch/sim/src/up_devconsole.c b/nuttx/arch/sim/src/up_devconsole.c
new file mode 100644
index 000000000..b55df53df
--- /dev/null
+++ b/nuttx/arch/sim/src/up_devconsole.c
@@ -0,0 +1,136 @@
+/************************************************************
+ * up_devconsole.c
+ *
+ *   Copyright (C) 2007 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * 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 Gregory Nutt 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.
+ *
+ ************************************************************/
+
+/************************************************************
+ * Included Files
+ ************************************************************/
+
+#include <nuttx/config.h>
+#include <sys/types.h>
+
+#include <stdio.h>
+#include <errno.h>
+
+#include <nuttx/fs.h>
+
+#include "up_internal.h"
+
+/************************************************************
+ * Definitions
+ ************************************************************/
+
+#define READ   3
+#define WRITE  4
+
+/************************************************************
+ * Private Function Prototypes
+ ************************************************************/
+
+static ssize_t devconsole_read(struct file *, char *, size_t);
+static ssize_t devconsole_write(struct file *, const char *, size_t);
+
+/************************************************************
+ * Private Data
+ ************************************************************/
+
+static struct file_operations devconsole_fops =
+{
+  .read		= devconsole_read,
+  .write	= devconsole_write,
+};
+
+/************************************************************
+ * Private Functions
+ ************************************************************/
+
+static inline int up_read(int fd, void* buf, size_t count)
+{
+  uint32 result;
+
+  __asm__ volatile ("int $0x80" \
+                    : "=a" (result) \
+                    : "0" (READ), "b" ((uint32)(fd)), "c" ((uint32)(buf)), "d" ((uint32)(count)) \
+                    : "memory");
+
+  return (int)result;
+}
+
+static inline int up_write(int fd, const void* buf, size_t count)
+{
+  uint32 result;
+
+  __asm__ volatile ("int $0x80" \
+                    : "=a" (result) \
+                    : "0" (WRITE), "b" ((uint32)(fd)), "c" ((uint32)(buf)), "d" ((uint32)(count)) \
+                    : "memory");
+
+  return (int)result;
+}
+
+static inline int up_check_result(int result)
+{
+  if (result >= (uint32)(-(128 + 1)))
+    {
+      *get_errno_ptr() = -result;
+      result = ERROR;
+    }
+  return result;
+}
+
+static ssize_t devconsole_read(struct file *filp, char *buffer, size_t len)
+{
+  return up_check_result(up_read(1, buffer, len));
+}
+
+static ssize_t devconsole_write(struct file *filp, const char *buffer, size_t len)
+{
+  return up_check_result(up_write(1, buffer, len));
+}
+
+/************************************************************
+ * Public Funtions
+ ************************************************************/
+
+void up_devconsole(void)
+{
+  (void)register_inode("/dev/console", &devconsole_fops, 0666, NULL);
+}
+
+int up_putc(int ch)
+{
+  char b = ch;
+  (void)up_write(1, &b, 1);
+  return ch;
+}
diff --git a/nuttx/arch/sim/src/up_exit.c b/nuttx/arch/sim/src/up_exit.c
new file mode 100644
index 000000000..a0a3bdc9a
--- /dev/null
+++ b/nuttx/arch/sim/src/up_exit.c
@@ -0,0 +1,123 @@
+/************************************************************
+ * up_exit.c
+ *
+ *   Copyright (C) 2007 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * 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 Gregory Nutt 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.
+ *
+ ************************************************************/
+
+/************************************************************
+ * Included Files
+ ************************************************************/
+
+#include <nuttx/config.h>
+#include <sys/types.h>
+#include <sched.h>
+#include <debug.h>
+#include <nuttx/arch.h>
+#include "os_internal.h"
+#include "up_internal.h"
+
+/************************************************************
+ * Private Definitions
+ ************************************************************/
+
+/************************************************************
+ * Private Data
+ ************************************************************/
+
+/************************************************************
+ * Private Funtions
+ ************************************************************/
+
+/************************************************************
+ * Public Funtions
+ ************************************************************/
+
+/************************************************************
+ * Name: _exit
+ *
+ * Description:
+ *   This function causes the currently executing task to cease
+ *   to exist.  This is a special case of task_delete().
+ *
+ ************************************************************/
+
+void _exit(int status)
+{
+  _TCB* tcb = (_TCB*)g_readytorun.head;
+
+  dbg("TCB=%p exitting\n", tcb);
+
+  /* Remove the tcb task from the ready-to-run list.  We can
+   * ignore the return value because we know that a context
+   * switch is needed.
+   */
+
+  (void)sched_removereadytorun(tcb);
+
+  /* Move the TCB to the specified blocked task list and delete it */
+
+  sched_addblocked(tcb, TSTATE_TASK_INACTIVE);
+  task_delete(tcb->pid);
+
+  /* If there are any pending tasks, then add them to the g_readytorun
+   * task list now
+   */
+
+  if (g_pendingtasks.head)
+    {
+      (void)sched_mergepending();
+    }
+
+  /* Now, perform the context switch to the new ready-to-run task at the
+   * head of the list.
+   */
+
+  tcb = (_TCB*)g_readytorun.head;
+  dbg("New Active Task TCB=%p\n", tcb);
+
+  /* The way that we handle signals in the simulation is kind of
+   * a kludge.  This would be unsafe in a truly multi-threaded, interrupt
+   * driven environment.
+   */
+
+  if (tcb->xcp.sigdeliver)
+    {
+      dbg("Delivering signals TCB=%p\n", tcb);
+      ((sig_deliver_t)tcb->xcp.sigdeliver)(tcb);
+      tcb->xcp.sigdeliver = NULL;
+    }
+
+  /* Then switch contexts */
+
+  up_longjmp(tcb->xcp.regs, 1);
+}
+
diff --git a/nuttx/arch/sim/src/up_head.c b/nuttx/arch/sim/src/up_head.c
new file mode 100644
index 000000000..9d1ccf153
--- /dev/null
+++ b/nuttx/arch/sim/src/up_head.c
@@ -0,0 +1,77 @@
+/************************************************************
+ * up_head.c
+ *
+ *   Copyright (C) 2007 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * 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 Gregory Nutt 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.
+ *
+ ************************************************************/
+
+/************************************************************
+ * Included Files
+ ************************************************************/
+
+#include <sys/types.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <setjmp.h>
+#include <assert.h>
+#include <nuttx/os_external.h>
+#include <nuttx/arch.h>
+
+/************************************************************
+ * Private Data
+ ************************************************************/
+
+static jmp_buf sim_abort;
+
+/************************************************************
+ * Global Funtions
+ ************************************************************/
+
+int main(int argc, char **argv, char **envp)
+{
+  if (setjmp(sim_abort) == 0)
+    {
+      os_start();
+    }
+  return 0;
+}
+
+void up_assert(const ubyte *filename, uint32 line)
+{
+  fprintf(stderr, "Assertion failed at file:%s line: %d\n", filename, line);
+  longjmp(sim_abort, 1);
+}
+
+void up_assert_code(const ubyte *filename, uint32 line, uint16 code)
+{
+  fprintf(stderr, "Assertion failed at file:%s line: %d error code: %d\n", filename, line, code);
+  longjmp(sim_abort, 1);
+}
diff --git a/nuttx/arch/sim/src/up_idle.c b/nuttx/arch/sim/src/up_idle.c
new file mode 100644
index 000000000..b40b2e3d8
--- /dev/null
+++ b/nuttx/arch/sim/src/up_idle.c
@@ -0,0 +1,84 @@
+/************************************************************
+ * up_idle.c
+ *
+ *   Copyright (C) 2007 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * 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 Gregory Nutt 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.
+ *
+ ************************************************************/
+
+/************************************************************
+ * Included Files
+ ************************************************************/
+
+#include <nuttx/config.h>
+#include <sys/types.h>
+#include <nuttx/arch.h>
+#include "up_internal.h"
+
+/************************************************************
+ * Private Definitions
+ ************************************************************/
+
+/************************************************************
+ * Private Data
+ ************************************************************/
+
+/************************************************************
+ * Private Funtions
+ ************************************************************/
+
+/************************************************************
+ * Public Funtions
+ ************************************************************/
+
+/************************************************************
+ * Name: up_idle
+ *
+ * Description:
+ *   up_idle() is the logic that will be executed when their
+ *   is no other ready-to-run task.  This is processor idle
+ *   time and will continue until some interrupt occurs to
+ *   cause a context switch from the idle task.
+ *
+ *   Processing in this state may be processor-specific. e.g.,
+ *   this is where power management operations might be
+ *   performed.
+ *
+ ************************************************************/
+
+void up_idle(void)
+{
+  /* If the system, then process timer interrupts.  Hopefully
+   * something will wake up.
+   */
+
+  sched_process_timer();
+}
+
diff --git a/nuttx/arch/sim/src/up_initialize.c b/nuttx/arch/sim/src/up_initialize.c
new file mode 100644
index 000000000..90b0b49e4
--- /dev/null
+++ b/nuttx/arch/sim/src/up_initialize.c
@@ -0,0 +1,88 @@
+/************************************************************
+ * up_initialize.c
+ *
+ *   Copyright (C) 2007 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * 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 Gregory Nutt 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.
+ *
+ ************************************************************/
+
+/************************************************************
+ * Included Files
+ ************************************************************/
+
+#include <nuttx/config.h>
+#include <sys/types.h>
+#include <nuttx/arch.h>
+#include <nuttx/fs.h>
+#include "up_internal.h"
+
+/************************************************************
+ * Private Definitions
+ ************************************************************/
+
+/************************************************************
+ * Private Data
+ ************************************************************/
+
+/************************************************************
+ * Private Funtions
+ ************************************************************/
+
+/************************************************************
+ * Public Funtions
+ ************************************************************/
+
+/************************************************************
+ * Name: up_initialize
+ *
+ * Description:
+ *   up_initialize will be called once during OS
+ *   initialization after the basic OS services have been
+ *   initialized.  The architecture specific details of
+ *   initializing the OS will be handled here.  Such things as
+ *   setting up interrupt service routines, starting the
+ *   clock, and registering device drivers are some of the
+ *   things that are different for each processor and hardware
+ *   platform.
+ *
+ *   up_initialize is called after the OS initialized but
+ *   before the init process has been started and before the
+ *   libraries have been initialized.  OS services and driver
+ *   services are available.
+ *
+ ************************************************************/
+
+void up_initialize(void)
+{
+  /* Register devices */
+
+  devnull_register();   /* Standard /dev/null */
+  up_devconsole();      /* Our private /dev/console */
+}
diff --git a/nuttx/arch/sim/src/up_initialstate.c b/nuttx/arch/sim/src/up_initialstate.c
new file mode 100644
index 000000000..ec3e50991
--- /dev/null
+++ b/nuttx/arch/sim/src/up_initialstate.c
@@ -0,0 +1,81 @@
+/************************************************************
+ * up_initialstate.c
+ *
+ *   Copyright (C) 2007 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * 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 Gregory Nutt 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.
+ *
+ ************************************************************/
+
+/************************************************************
+ * Included Files
+ ************************************************************/
+
+#include <nuttx/config.h>
+#include <sys/types.h>
+#include <string.h>
+#include <nuttx/arch.h>
+#include "up_internal.h"
+
+/************************************************************
+ * Private Definitions
+ ************************************************************/
+
+/************************************************************
+ * Private Data
+ ************************************************************/
+
+/************************************************************
+ * Private Funtions
+ ************************************************************/
+
+/************************************************************
+ * Public Funtions
+ ************************************************************/
+
+/************************************************************
+ * Name: up_initial_state
+ *
+ * Description:
+ *   A new thread is being started and a new TCB
+ *   has been created. This function is called to initialize
+ *   the processor specific portions of the new TCB.
+ *
+ *   This function must setup the intial architecture registers
+ *   and/or  stack so that execution will begin at tcb->start
+ *   on the next context switch.
+ *
+ ************************************************************/
+
+void up_initial_state(_TCB *tcb)
+{
+  memset(&tcb->xcp, 0, sizeof(struct xcptcontext));
+  tcb->xcp.regs[JB_SP] = (uint32)tcb->adj_stack_ptr;
+  tcb->xcp.regs[JB_PC] = (uint32)tcb->start;
+}
diff --git a/nuttx/arch/sim/src/up_internal.h b/nuttx/arch/sim/src/up_internal.h
new file mode 100644
index 000000000..29defe029
--- /dev/null
+++ b/nuttx/arch/sim/src/up_internal.h
@@ -0,0 +1,91 @@
+/**************************************************************************
+ * up_internal.h
+ *
+ *   Copyright (C) 2007 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * 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 Gregory Nutt 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_UP_INTERNAL_H
+#define __ARCH_UP_INTERNAL_H
+
+/**************************************************************************
+ * Included Files
+ **************************************************************************/
+
+#include <nuttx/irq.h>
+
+/**************************************************************************
+ * Public Definitions
+ **************************************************************************/
+
+/* Storage order: %ebx, $esi, %edi, %ebp, sp, and return PC */
+#ifdef __ASSEMBLY__
+# define JB_EBX (0*4)
+# define JB_ESI (1*4)
+# define JB_EDI (2*4)
+# define JB_EBP (3*4)
+# define JB_SP  (4*4)
+# define JB_PC  (5*4)
+#else
+# define JB_EBX (0)
+# define JB_ESI (1)
+# define JB_EDI (2)
+# define JB_EBP (3)
+# define JB_SP  (4)
+# define JB_PC  (5)
+#endif /* __ASSEMBLY__ */
+
+#define SIM_HEAP_SIZE (4*1024*1024)
+
+/**************************************************************************
+ * Public Types
+ **************************************************************************/
+
+/**************************************************************************
+ * Public Variables
+ **************************************************************************/
+
+/**************************************************************************
+ * Public Function Prototypes
+ **************************************************************************/
+
+#ifndef __ASSEMBLY__
+/* up_setjmp.S ************************************************************/
+
+extern int  up_setjmp(int *jb);
+extern void up_longjmp(int *jb, int val) __attribute__ ((noreturn));
+
+/* up_devconsole **********************************************************/
+
+extern void up_devconsole(void);
+
+#endif /* __ASSEMBLY__ */
+#endif /* __ARCH_UP_INTERNAL_H */
diff --git a/nuttx/arch/sim/src/up_interruptcontext.c b/nuttx/arch/sim/src/up_interruptcontext.c
new file mode 100644
index 000000000..ad1eb74d7
--- /dev/null
+++ b/nuttx/arch/sim/src/up_interruptcontext.c
@@ -0,0 +1,74 @@
+/************************************************************
+ * up_interruptcontext.c
+ *
+ *   Copyright (C) 2007 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * 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 Gregory Nutt 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.
+ *
+ ************************************************************/
+
+/************************************************************
+ * Included Files
+ ************************************************************/
+
+#include <nuttx/config.h>
+#include <sys/types.h>
+#include <nuttx/arch.h>
+#include "up_internal.h"
+
+/************************************************************
+ * Private Definitions
+ ************************************************************/
+
+/************************************************************
+ * Private Data
+ ************************************************************/
+
+/************************************************************
+ * Private Funtions
+ ************************************************************/
+
+/************************************************************
+ * Public Funtions
+ ************************************************************/
+
+/************************************************************
+ * Name: up_interrupt_context
+ *
+ * Description:
+ *   Return TRUE is we are currently executing in
+ *   the interrupt handler context.
+ ************************************************************/
+
+boolean up_interrupt_context(void)
+{
+  /* The simulation is never in the interrupt state */
+  return FALSE;
+}
+
diff --git a/nuttx/arch/sim/src/up_releasepending.c b/nuttx/arch/sim/src/up_releasepending.c
new file mode 100644
index 000000000..8a494a354
--- /dev/null
+++ b/nuttx/arch/sim/src/up_releasepending.c
@@ -0,0 +1,118 @@
+/************************************************************
+ * up_releasepending.c
+ *
+ *   Copyright (C) 2007 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * 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 Gregory Nutt 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.
+ *
+ ************************************************************/
+
+/************************************************************
+ * Included Files
+ ************************************************************/
+
+#include <nuttx/config.h>
+#include <sys/types.h>
+#include <sched.h>
+#include <debug.h>
+#include <nuttx/arch.h>
+#include "os_internal.h"
+#include "up_internal.h"
+
+/************************************************************
+ * Private Definitions
+ ************************************************************/
+
+/************************************************************
+ * Private Data
+ ************************************************************/
+
+/************************************************************
+ * Private Funtions
+ ************************************************************/
+
+/************************************************************
+ * Public Funtions
+ ************************************************************/
+
+/************************************************************
+ * Name: up_release_pending
+ *
+ * Description:
+ *   Release and ready-to-run tasks that have
+ *   collected in the pending task list.  This can call a
+ *   context switch if a new task is placed at the head of
+ *   the ready to run list.
+ *
+ ************************************************************/
+
+void up_release_pending(void)
+{
+  _TCB *rtcb = (_TCB*)g_readytorun.head;
+
+  dbg("From TCB=%p\n", rtcb);
+
+  /* Merge the g_pendingtasks list into the g_readytorun task list */
+
+  /* sched_lock(); */
+  if (sched_mergepending())
+    {
+      /* The currently active task has changed! Copy the exception context
+       * into the TCB of the task that was currently active. if up_setjmp
+       * returns a non-zero value, then this is really the previously
+       * running task restarting!
+       */
+
+      if (!up_setjmp(rtcb->xcp.regs))
+        {
+          /* Restore the exception context of the rtcb at the (new) head 
+           * of the g_readytorun task list.
+           */
+
+          rtcb = (_TCB*)g_readytorun.head;
+          dbg("New Active Task TCB=%p\n", rtcb);
+
+          /* The way that we handle signals in the simulation is kind of
+           * a kludge.  This would be unsafe in a truly multi-threaded, interrupt
+           * driven environment.
+           */
+
+          if (rtcb->xcp.sigdeliver)
+            {
+              dbg("Delivering signals TCB=%p\n", rtcb);
+              ((sig_deliver_t)rtcb->xcp.sigdeliver)(rtcb);
+              rtcb->xcp.sigdeliver = NULL;
+            }
+
+           /* Then switch contexts */
+
+          up_longjmp(rtcb->xcp.regs, 1);
+        }
+    }
+}
diff --git a/nuttx/arch/sim/src/up_releasestack.c b/nuttx/arch/sim/src/up_releasestack.c
new file mode 100644
index 000000000..5fc950c6a
--- /dev/null
+++ b/nuttx/arch/sim/src/up_releasestack.c
@@ -0,0 +1,81 @@
+/************************************************************
+ * up_releasestack.c
+ *
+ *   Copyright (C) 2007 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * 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 Gregory Nutt 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.
+ *
+ ************************************************************/
+
+/************************************************************
+ * Included Files
+ ************************************************************/
+
+#include <nuttx/config.h>
+#include <sys/types.h>
+#include <stdlib.h>
+#include <nuttx/arch.h>
+#include "up_internal.h"
+
+/************************************************************
+ * Private Definitions
+ ************************************************************/
+
+/************************************************************
+ * Private Data
+ ************************************************************/
+
+/************************************************************
+ * Private Funtions
+ ************************************************************/
+
+/************************************************************
+ * Public Funtions
+ ************************************************************/
+
+/************************************************************
+ * Name: up_release_stack
+ *
+ * Description:
+ *   A task has been stopped. Free all stack
+ *   related resources retained int the defunct TCB.
+ *
+ ************************************************************/
+
+void up_release_stack(_TCB *dtcb)
+{
+  if (dtcb->stack_alloc_ptr)
+    {
+      free(dtcb->stack_alloc_ptr);
+    }
+
+  dtcb->stack_alloc_ptr = NULL;
+  dtcb->adj_stack_size  = 0;
+  dtcb->adj_stack_ptr   = NULL;
+}
diff --git a/nuttx/arch/sim/src/up_reprioritizertr.c b/nuttx/arch/sim/src/up_reprioritizertr.c
new file mode 100644
index 000000000..d4d91a88e
--- /dev/null
+++ b/nuttx/arch/sim/src/up_reprioritizertr.c
@@ -0,0 +1,169 @@
+/************************************************************
+ * up_reprioritizertr.c
+ *
+ *   Copyright (C) 2007 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * 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 Gregory Nutt 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.
+ *
+ ************************************************************/
+
+/************************************************************
+ * Included Files
+ ************************************************************/
+
+#include <nuttx/config.h>
+#include <sys/types.h>
+#include <sched.h>
+#include <debug.h>
+#include <nuttx/arch.h>
+#include "os_internal.h"
+#include "up_internal.h"
+
+/************************************************************
+ * Private Definitions
+ ************************************************************/
+
+/************************************************************
+ * Private Data
+ ************************************************************/
+
+/************************************************************
+ * Private Funtions
+ ************************************************************/
+
+/************************************************************
+ * Public Funtions
+ ************************************************************/
+
+/************************************************************
+ * Name: up_reprioritize_rtr
+ *
+ * Description:
+ *   Called when the priority of a running or
+ *   ready-to-run task changes and the reprioritization will 
+ *   cause a context switch.  Two cases:
+ *
+ *   1) The priority of the currently running task drops and the next
+ *      task in the ready to run list has priority.
+ *   2) An idle, ready to run task's priority has been raised above the
+ *      the priority of the current, running task and it now has the
+ *      priority.
+ *
+ * Inputs:
+ *   tcb: The TCB of the task that has been reprioritized
+ *   priority: The new task priority
+ *
+ ************************************************************/
+
+void up_reprioritize_rtr(_TCB *tcb, ubyte priority)
+{
+  /* Verify that the caller is sane */
+
+  if (tcb->task_state < FIRST_READY_TO_RUN_STATE ||
+      tcb->task_state > LAST_READY_TO_RUN_STATE ||
+      priority < SCHED_PRIORITY_MIN || 
+      priority > SCHED_PRIORITY_MAX)
+    {
+       PANIC(OSERR_BADREPRIORITIZESTATE);
+    }
+  else
+    {
+      _TCB *rtcb = (_TCB*)g_readytorun.head;
+      boolean switch_needed;
+
+      dbg("TCB=%p PRI=%d\n", tcb, priority);
+
+      /* Remove the tcb task from the ready-to-run list.
+       * sched_removereadytorun will return TRUE if we just
+       * remove the head of the ready to run list.
+       */
+
+      switch_needed = sched_removereadytorun(tcb);
+
+      /* Setup up the new task priority */
+
+      tcb->sched_priority = (ubyte)priority;
+
+      /* Return the task to the specified blocked task list.
+       * sched_addreadytorun will return TRUE if the task was
+       * added to the new list.  We will need to perform a context
+       * switch only if the EXCLUSIVE or of the two calls is non-zero
+       * (i.e., one and only one the calls changes the head of the
+       * ready-to-run list).
+       */
+
+      switch_needed ^= sched_addreadytorun(tcb);
+
+      /* Now, perform the context switch if one is needed */
+
+      if (switch_needed)
+        {
+          /* If we are going to do a context switch, then now is the right
+           * time to add any pending tasks back into the ready-to-run list.
+           * task list now
+           */
+
+          if (g_pendingtasks.head)
+            {
+              sched_mergepending();
+            }
+
+          /* Copy the exception context into the TCB at the (old) head of the
+           * g_readytorun Task list. if up_setjmp returns a non-zero
+           * value, then this is really the previously running task restarting!
+           */
+
+          if (!up_setjmp(rtcb->xcp.regs))
+            {
+              /* Restore the exception context of the rtcb at the (new) head 
+               * of the g_readytorun task list.
+               */
+
+              rtcb = (_TCB*)g_readytorun.head;
+              dbg("New Active Task TCB=%p\n", rtcb);
+
+              /* The way that we handle signals in the simulation is kind of
+               * a kludge.  This would be unsafe in a truly multi-threaded, interrupt
+               * driven environment.
+               */
+
+              if (rtcb->xcp.sigdeliver)
+                {
+                  dbg("Delivering signals TCB=%p\n", rtcb);
+                  ((sig_deliver_t)rtcb->xcp.sigdeliver)(rtcb);
+                  rtcb->xcp.sigdeliver = NULL;
+                }
+
+              /* Then switch contexts */
+
+              up_longjmp(rtcb->xcp.regs, 1);
+            }
+        }
+    }
+}
diff --git a/nuttx/arch/sim/src/up_schedulesigaction.c b/nuttx/arch/sim/src/up_schedulesigaction.c
new file mode 100644
index 000000000..6e6d13911
--- /dev/null
+++ b/nuttx/arch/sim/src/up_schedulesigaction.c
@@ -0,0 +1,109 @@
+/************************************************************
+ * up_schedulesigaction.c
+ *
+ *   Copyright (C) 2007 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * 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 Gregory Nutt 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.
+ *
+ ************************************************************/
+
+/************************************************************
+ * Included Files
+ ************************************************************/
+
+#include <nuttx/config.h>
+#include <sys/types.h>
+#include <sched.h>
+#include <debug.h>
+#include <nuttx/arch.h>
+#include "os_internal.h"
+#include "up_internal.h"
+
+/************************************************************
+ * Private Definitions
+ ************************************************************/
+
+/************************************************************
+ * Private Data
+ ************************************************************/
+
+/************************************************************
+ * Private Funtions
+ ************************************************************/
+
+/************************************************************
+ * Public Funtions
+ ************************************************************/
+
+/************************************************************
+ * Name: up_schedule_sigaction
+ *
+ * Description:
+ *   This function is called by the OS when one or more
+ *   signal handling actions have been queued for execution.
+ *   The architecture specific code must configure things so
+ *   that the 'igdeliver' callback is executed on the thread
+ *   specified by 'tcb' as soon as possible.
+ *
+ *   This function may be called from interrupt handling logic.
+ *
+ *   This operation should not cause the task to be unblocked
+ *   nor should it cause any immediate execution of sigdeliver.
+ *   Typically, a few cases need to be considered:
+ *
+ *   (1) This function may be called from an interrupt handler
+ *       During interrupt processing, all xcptcontext structures
+ *       should be valid for all tasks.  That structure should
+ *       be modified to invoke sigdeliver() either on return
+ *       from (this) interrupt or on some subsequent context
+ *       switch to the recipient task.
+ *   (2) If not in an interrupt handler and the tcb is NOT
+ *       the currently executing task, then again just modify
+ *       the saved xcptcontext structure for the recipient
+ *       task so it will invoke sigdeliver when that task is
+ *       later resumed.
+ *   (3) If not in an interrupt handler and the tcb IS the
+ *       currently executing task -- just call the signal
+ *       handler now.
+ *
+ ************************************************************/
+
+void up_schedule_sigaction(_TCB *tcb, sig_deliver_t sigdeliver)
+{
+  /* We don't have to anything complex of the simulated target */
+
+  if (tcb == (_TCB*)g_readytorun.head)
+    {
+      sigdeliver(tcb);
+    }
+  else
+    {
+      tcb->xcp.sigdeliver = sigdeliver;
+    }
+}
diff --git a/nuttx/arch/sim/src/up_setjmp.S b/nuttx/arch/sim/src/up_setjmp.S
new file mode 100644
index 000000000..96b9bfee8
--- /dev/null
+++ b/nuttx/arch/sim/src/up_setjmp.S
@@ -0,0 +1,129 @@
+/**************************************************************************
+ * up_setjmp.S
+ *
+ *   Copyright (C) 2007 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * 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 Gregory Nutt 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.
+ *
+ **************************************************************************/
+
+/**************************************************************************
+ * Conditional Compilation Options
+ **************************************************************************/
+
+/**************************************************************************
+ * Included Files
+ **************************************************************************/
+
+#include "up_internal.h"
+
+/**************************************************************************
+ * Private Definitions
+ **************************************************************************/
+
+/**************************************************************************
+ * Private Types
+ **************************************************************************/
+
+/**************************************************************************
+ * Private Function Prototypes
+ **************************************************************************/
+
+/**************************************************************************
+ * Global Variables
+ **************************************************************************/
+
+/**************************************************************************
+ * Private Variables
+ **************************************************************************/
+
+/**************************************************************************
+ * Private Functions
+ **************************************************************************/
+
+/**************************************************************************
+ * Public Functions
+ **************************************************************************/
+
+	.text
+	.globl	up_setjmp
+	.type	up_setjmp, @function
+up_setjmp:
+
+	/* %ebx, %esi, %edi, and %ebp must be preserved.
+	 * save %ebx, $esi, and %edi now... */
+
+        movl	4(%esp), %eax
+        movl	%ebx, (JB_EBX)(%eax)
+        movl	%esi, (JB_ESI)(%eax)
+        movl	%edi, (JB_EDI)(%eax)
+
+        /* Save the value of SP as will be after we return */
+
+        leal	4(%esp), %ecx
+        movl	%ecx, (JB_SP)(%eax)
+
+        /* Save the return PC */
+
+        movl	0(%esp), %ecx
+        movl	%ecx, (JB_PC)(%eax)
+
+        /* Save the framepointer */
+
+        movl %ebp, (JB_EBP)(%eax)
+
+	/* And return 0 */
+
+	xorl    %eax, %eax
+        ret
+	.size	up_setjmp, . - up_setjmp
+
+	.globl	up_longjmp
+	.type	up_longjmp, @function
+up_longjmp:
+        movl	4(%esp), %ecx      /* U_pthread_jmpbuf in %ecx.  */
+        movl	8(%esp), %eax      /* Second argument is return value.  */
+
+        /* Save the return address now.  */
+
+        movl (JB_PC)(%ecx), %edx
+
+        /* Restore registers.  */
+
+        movl (JB_EBX)(%ecx), %ebx
+        movl (JB_ESI)(%ecx), %esi
+        movl (JB_EDI)(%ecx), %edi
+        movl (JB_EBP)(%ecx), %ebp
+        movl (JB_SP)(%ecx), %esp
+
+        /* Jump to saved PC.  */
+
+        jmp *%edx
+	.size up_longjmp, . - up_longjmp
+
diff --git a/nuttx/arch/sim/src/up_unblocktask.c b/nuttx/arch/sim/src/up_unblocktask.c
new file mode 100644
index 000000000..bf3148506
--- /dev/null
+++ b/nuttx/arch/sim/src/up_unblocktask.c
@@ -0,0 +1,146 @@
+/************************************************************
+ * up_unblocktask.c
+ *
+ *   Copyright (C) 2007 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * 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 Gregory Nutt 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.
+ *
+ ************************************************************/
+
+/************************************************************
+ * Included Files
+ ************************************************************/
+
+#include <nuttx/config.h>
+#include <sys/types.h>
+#include <sched.h>
+#include <debug.h>
+#include <nuttx/arch.h>
+#include "os_internal.h"
+#include "up_internal.h"
+
+/************************************************************
+ * Private Definitions
+ ************************************************************/
+
+/************************************************************
+ * Private Data
+ ************************************************************/
+
+/************************************************************
+ * Private Funtions
+ ************************************************************/
+
+/************************************************************
+ * Public Funtions
+ ************************************************************/
+
+/************************************************************
+ * Name: up_unblock_task
+ *
+ * Description:
+ *   A task is currently in an inactive task list
+ *   but has been prepped to execute.  Move the TCB to the
+ *   ready-to-run list, restore its context, and start execution.
+ *
+ * Inputs:
+ *   tcb: Refers to the tcb to be unblocked.  This tcb is
+ *     in one of the waiting tasks lists.  It must be moved to
+ *     the ready-to-run list and, if it is the highest priority
+ *     ready to run taks, executed.
+ *
+ ************************************************************/
+
+void up_unblock_task(_TCB *tcb)
+{
+  /* Verify that the context switch can be performed */
+  if ((tcb->task_state < FIRST_BLOCKED_STATE) ||
+      (tcb->task_state > LAST_BLOCKED_STATE))
+    {
+      PANIC(OSERR_BADUNBLOCKSTATE);
+    }
+  else
+    {
+      _TCB *rtcb = (_TCB*)g_readytorun.head;
+
+      dbg("Unblocking TCB=%p\n", tcb);
+
+     /* Remove the task from the blocked task list */
+
+     sched_removeblocked(tcb);
+
+     /* Reset its timeslice.  This is only meaningful for round
+      * robin tasks but it doesn't here to do it for everything
+      */
+
+#if CONFIG_RR_INTERVAL > 0
+     tcb->timeslice = CONFIG_RR_INTERVAL;
+#endif
+
+     /* Add the task in the correct location in the prioritized
+      * g_readytorun task list
+      */
+
+     if (sched_addreadytorun(tcb))
+       {
+         /* The currently active task has changed! Copy the exception context
+          * into the TCB of the task that was previously active.  if 
+          * up_setjmp returns a non-zero value, then this is really the
+          * previously running task restarting!
+          */
+
+         if (!up_setjmp(rtcb->xcp.regs))
+           {
+             /* Restore the exception context of the new task that is ready to
+              * run (probably tcb).  This is the new rtcb at the head of the
+              * g_readytorun task list.
+              */
+
+             rtcb = (_TCB*)g_readytorun.head;
+             dbg("New Active Task TCB=%p\n", rtcb);
+
+              /* The way that we handle signals in the simulation is kind of
+               * a kludge.  This would be unsafe in a truly multi-threaded, interrupt
+               * driven environment.
+               */
+
+              if (rtcb->xcp.sigdeliver)
+                {
+                  dbg("Delivering signals TCB=%p\n", rtcb);
+                  ((sig_deliver_t)rtcb->xcp.sigdeliver)(rtcb);
+                  rtcb->xcp.sigdeliver = NULL;
+                }
+
+              /* Then switch contexts */
+
+             up_longjmp(rtcb->xcp.regs, 1);
+           }
+       }
+    }
+}
diff --git a/nuttx/arch/sim/src/up_usestack.c b/nuttx/arch/sim/src/up_usestack.c
new file mode 100644
index 000000000..26bf14b21
--- /dev/null
+++ b/nuttx/arch/sim/src/up_usestack.c
@@ -0,0 +1,100 @@
+/************************************************************
+ * up_usestack.c
+ *
+ *   Copyright (C) 2007 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * 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 Gregory Nutt 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.
+ *
+ ************************************************************/
+
+/************************************************************
+ * Included Files
+ ************************************************************/
+
+#include <nuttx/config.h>
+#include <sys/types.h>
+#include <debug.h>
+#include <nuttx/arch.h>
+#include "os_internal.h"
+#include "up_internal.h"
+
+/************************************************************
+ * Private Definitions
+ ************************************************************/
+
+/************************************************************
+ * Private Data
+ ************************************************************/
+
+/************************************************************
+ * Private Funtions
+ ************************************************************/
+
+/************************************************************
+ * Public Funtions
+ ************************************************************/
+
+/************************************************************
+ * Name: up_use_stack
+ *
+ * Description:
+ *   Setup up stack-related information in the TCB
+ *   using pre-allocated stack memory
+ *
+ *   The following TCB fields must be initialized:
+ *   adj_stack_size: Stack size after adjustment for hardware,
+ *     processor, etc.  This value is retained only for debug
+ *     purposes.
+ *   stack_alloc_ptr: Pointer to allocated stack
+ *   adj_stack_ptr: Adjusted StatckAllocPtr for HW.  The
+ *     initial value of the stack pointer.
+ *
+ * Inputs:
+ *   tcb: The TCB of new task
+ *   stack_size: The allocated stack size.
+ *
+ ************************************************************/
+
+STATUS up_use_stack(_TCB *tcb, uint32 *stack, uint32 stack_size)
+{
+  /* Move up to next even word boundary if necessary */
+
+  uint32 adj_stack_size = stack_size & ~3;
+  uint32 adj_stack_words = adj_stack_size >> 2;
+
+  /* This is the address of the last word in the allocation */
+
+  uint32 *adj_stack_ptr = &stack[adj_stack_words - 1];
+
+  /* Save the values in the TCB */
+  tcb->adj_stack_size  = adj_stack_size;
+  tcb->stack_alloc_ptr = stack;
+  tcb->adj_stack_ptr   = adj_stack_ptr;
+  return OK;
+}