path: root/ecos/doc/sgml/user-guide/programming.sgml

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<part ID="user-guide-programming">
<TITLE>Programming With <productname>eCos</productname></TITLE>

<CHAPTER ID="PROGRAMMING-WITH-ECOS">
<TITLE>Programming With <productname>eCos</productname></TITLE>

<PARA>The following chapters of this manual comprise a simple tutorial
for configuring and building <productname>eCos</productname>, building and running <productname>eCos</productname> tests,
and finally building three stand-alone example programs which use
the  <productname>eCos</productname> API to perform some simple tasks.</PARA>

<PARA>You will need a properly installed <productname>eCos</productname> system, with the correct
versions of the GNU toolchain.<!-- <conditionaltext> --> On Windows
you will be using the bash command line interpreter that comes with
Cygwin, with the environment variables set as described in the
toolchain documentation.</PARA>

<SECT1 id="development-process">
<TITLE>The Development Process</TITLE>

<PARA>Most development projects using <productname>eCos</productname> would contain some (or
most) of  the following:</PARA>

<SECT2>
<TITLE><productname>eCos</productname> Configuration</TITLE>

<PARA><productname>eCos</productname> is configured to provide the desired API (the inclusion
of libc, uitron, and the disabling of certain undesired funtions,
etc.), and semantics (selecting scheduler, mutex behavior, etc.).
See <XREF LINKEND="CONFIGURING-AND-BUILDING-ECOS-FROM-SOURCE">.</PARA>

<PARA>It would normally make sense to enable <productname>eCos</productname> assertion checking
at this time as well, to catch as many programming errors during
the development phase as possible.</PARA>

<PARA>Note that it should not be necessary to spend much time on
<productname>eCos</productname> configuration initially. It may be important to perform fine
tuning to reduce the memory footprint and to improve performance
later when the product reaches a testable state.</PARA>
</SECT2>

<SECT2>
<TITLE>    Integrity check of the <productname>eCos</productname> configuration</TITLE>

<PARA>While we strive to thoroughly test <productname>eCos</productname>, the vast number
of configuration permutations mean that the particular configuration
parameters used for your project may not have been tested. Therefore,
we advise running the <productname>eCos</productname> tests after the project's
<productname>eCos</productname> configuration has been determined. See <XREF LINKEND="RUNNING-AN-ECOS-TEST-CASE">.</PARA>

<PARA>Obviously, this should be repeated if the configuration changes
later on in the development process.</PARA>
</SECT2>

<SECT2>
<TITLE>    Application Development - Target Neutral Part</TITLE>

<PARA>While your project is probably targeting a specific architecture
and platform, possibly custom hardware, it may be possible to perform
part of the application development using simulated or synthetic
targets.</PARA>

<PARA>There are three good reasons for doing this:</PARA>

<ITEMIZEDLIST>

<LISTITEM>
<PARA>It may be possible by this means to perform application
development in parallel with the design/implementation
of the target hardware, thus providing more time for developing
and testing functionality, and reducing time-to-market.</PARA>
</LISTITEM>

<LISTITEM>
<PARA>The build-run-debug-cycle may be faster when the application
does not have to be downloaded to a target via a serial interface.
Debugging is also likely to be more responsive when you do not have to
to communicate with the remote GDB stubs in RedBoot via serial. It
also removes the need for manually or automatically resetting the
target hardware.</PARA>
</LISTITEM>

<listitem>
<para>
New hardware can often be buggy. Comparing the behaviour of the
program on the hardware and in the simulator or synthetic target may
allow you to identify where the problems lie.
</para>
</listitem>

</ITEMIZEDLIST>

<PARA>This approach is possible because all targets (including
simulators and synthetic ones) provide the same basic API: that
is, kernel, libc, libm, uitron, infra, and to some extent, HAL and
IO.</PARA>

<PARA>Synthetic targets are especially suitable as they allow you
to construct simulations of elaborate devices by interaction with
the host system, where an IO device API can hide the details from
the application. When switching to hardware later in the development
cycle, the IO driver is properly implemented.
</para>

<para>
Simulators can also do this, but it all depends on the
design and capabilities of the simulator you use. Some, like
<ULINK URL="http://sources.redhat.com/sid">SID</ULINK> or
<ULINK URL="http://bochs.sourceforge.net/">Bochs</ULINK> provide
complete hardware emulation, while others just support enough of the
instruction set to run compiled code.
</PARA>

<PARA>Therefore, select a simulator or synthetic target and use
it for as long as possible for application development. That is,
configure for the selected target, build <productname>eCos</productname>, build the application
and link with <productname>eCos</productname>, run and debug. Repeat the latter two steps until
you are happy with it.</PARA>

<PARA>Obviously, at some time you will have to switch to the intended
target hardware, for example when adding target specific feature
support, for memory footprint/performance characterization,
and for final tuning of <productname>eCos</productname> and the application.</PARA>

</SECT2>

<SECT2>
<TITLE>    Application Development - Target Specific Part</TITLE>

<PARA>Repeat the build-run-debug-cycle while performing final tuning
and debugging of application. Remember to disable <productname>eCos</productname> assertion
checking if you are testing any performance-related aspects, it can
make a big difference.</PARA>

<PARA>It may be useful to switch between this and the previous step
repeatedly through the development process; use the simulator/synthetic
target for actual development, and use the target hardware to continually
check memory footprint and performance. There should be little cost
in switching between the two targets when using two separate build
trees. </PARA>
</SECT2>

</SECT1>

</CHAPTER>

<!-- ==================================================== -->

<CHAPTER ID="CONFIGURING-AND-BUILDING-ECOS-FROM-SOURCE"><!-- <conditionaltext> -->
<TITLE><!-- <xref> --><!-- <index></index> -->Configuring and Building <productname>eCos</productname> from Source</TITLE>

<PARA>This chapter documents the configuration of <productname>eCos</productname>. The process is
the same for any of the supported targets: you may select a
hardware target (if you have a board available), any one of the
simulators, or a synthetic target (if your host platform has synthetic
target support).</PARA>

<!-- ==================================================== -->

<SECT1 id="ecos-startup-configs">
<TITLE><!-- <xref> --><productname>eCos</productname> Start-up Configurations</TITLE>

<PARA>There are various ways to download an executable image to a
target board, and these involve different ways of preparing the
executable image. In the <productname>eCos</productname> Hardware Abstraction Layer (HAL package)
there are configuration options to support the different download
methods. <XREF LINKEND="user-guide-download-methods"> summarizes the
ways in which an <productname>eCos</productname> image can be prepared for different types of
download. This is not an exhaustive list, some targets define
additional start-up types of their own. Where a ROM Monitor is
mentioned, this will usually be RedBoot, although on some older, or
low resource, targets you may need to use CygMon or the GDB stubs ROM,
see the target documentation for details.</PARA>


<TABLE id="user-guide-download-methods">
<TITLE>Configuration for various download methods</TITLE>
<TGROUP COLS="2">
<THEAD>
<ROW>
<ENTRY>Download method</ENTRY>
<ENTRY>HAL configuration</ENTRY>
</ROW>
</THEAD>
<TBODY>
<ROW>
<ENTRY>Burn hardware ROM</ENTRY>
<ENTRY>&nbsp;ROM or ROMRAM start-up</ENTRY>
</ROW>
<ROW>
<ENTRY>Download to ROM emulator</ENTRY>
<ENTRY>&nbsp;ROM or ROMRAM start-up</ENTRY>
</ROW>
<ROW>
<ENTRY>Download to board with ROM Monitor</ENTRY>
<ENTRY>&nbsp;RAM start-up</ENTRY>
</ROW>
<ROW>
<ENTRY>Download to simulator without ROM Monitor</ENTRY>
<ENTRY>&nbsp;ROM start-up</ENTRY>
</ROW>
<ROW>
<ENTRY>Download to simulator with ROM Monitor</ENTRY>
<ENTRY>&nbsp;RAM start-up</ENTRY>
</ROW>
<ROW>
<ENTRY>Download to simulator ignoring devices</ENTRY>
<ENTRY>&nbsp;SIM configuration</ENTRY>
</ROW>
<ROW>
<ENTRY>Run synthetic target</ENTRY>
<ENTRY>&nbsp;RAM start-up</ENTRY>
</ROW>
</TBODY>
</TGROUP>
</TABLE>

<CAUTION>

<PARA>You cannot run an application configured for RAM start-up
on the simulator directly: it will fail during start-up. You can
only download it to the simulator if
you are already running RedBoot in the simulator,
as described in the toolchain documentation
or you load through the 
<EMPHASIS>SID </EMPHASIS>
GDB debugging component.  This is not the same as the simulated
stub, since it does not require a target program to be running to
get GDB to talk to it.  It can be done before letting the simulator
run
or you use the ELF loader component to get a program into memory.</PARA>

</CAUTION><!-- <label> --><!-- <conditionaltext> --><!-- NOTE</label> -->

<NOTE>
<PARA>Configuring <productname>eCos</productname>' HAL package for simulation should
rarely be needed for real development; binaries built with such
a kernel will not run on target boards at all,<!-- <conditionaltext> -->
and the MN10300 and
TX39 simulators can run binaries built for stdeval1 and jmr3904
target boards.
The main use for a ``simulation'' configuration
is if you are trying to work around problems with the device drivers
or with the simulator.  Also note that when using a TX39 system configured
for simulator start-up you should then invoke the simulator with 
the <OPTION>--board=jmr3904pal</OPTION>
option instead of 
<OPTION>--board=jmr3904</OPTION><!-- <conditionaltext> --></PARA>
</NOTE>

<NOTE>
<PARA>If your chosen architecture does not have simulator support,
then the combinations above that refer to the simulator do not apply.
Similarly, if your chosen platform does not have RedBoot
ROM support, the combinations listed above that use 
RedBoot do not apply.</PARA>
</NOTE>

<PARA>The debugging environment for most developers will be either
a hardware board or the simulator, in which case they will be able
to select a single HAL configuration.</PARA>

</SECT1>

<!-- ==================================================== -->

<SECT1 id="using-configtool-windows-linux">
<TITLE><!-- <index></index> -->
Configuration Tool on Windows and Linux Quick Start</TITLE>

<PARA><!-- <conditionaltext> --> 

This section described the GUI based configuration tool. This
tool is probably more suited to users who prefer GUI's. The next
section describes a CLI based tool which Unix users may
prefer. </PARA>

<PARA>Note that the use of the <application>Configuration Tool</application>
is described in detail in <XREF
LINKEND="THE-ECOS-CONFIGURATION-TOOL">.</PARA>

<PARA>The <application>Configuration Tool</application> (see <XREF LINKEND="PROGRAMMING-FIGURE-CONFIGURATION-TOOL">)
has five main elements: the <EMPHASIS>configuration window</EMPHASIS>,
the <emphasis>conflicts window</emphasis>,
the <EMPHASIS>properties window</EMPHASIS>, the <!-- <xref> --><EMPHASIS>short
description window</EMPHASIS>,
and the <EMPHASIS>output window</EMPHASIS>.</PARA>

<FIGURE ID="PROGRAMMING-FIGURE-CONFIGURATION-TOOL">
<TITLE>Configuration Tool</TITLE><!-- <xref> -->
<GRAPHIC ENTITYREF="programming-graphic1"></GRAPHIC>
</FIGURE>

<PARA>Start by opening the templates window via <GUIMENUITEM>Build-&#62;Templates</GUIMENUITEM>.
Select the desired target (see <XREF LINKEND="FIGURE-TEMPLATE-SELECTION">).</PARA>

<FIGURE ID="FIGURE-TEMPLATE-SELECTION">
<TITLE>Template selection</TITLE><!-- <xref> -->
<GRAPHIC ENTITYREF="programming-graphic2"></GRAPHIC>
</FIGURE>

<PARA>Make sure that the configuration is correct for the target
in terms of endianness, CPU model, Startup type, etc. (see <XREF LINKEND="CONFIGURING-FOR-THE-TARGET">).</PARA>

<FIGURE ID="CONFIGURING-FOR-THE-TARGET">
<TITLE><!-- <conditionaltext> --><!-- <xref> -->Configuring
for the target</TITLE>
<GRAPHIC ENTITYREF="programming-graphic3"></GRAPHIC>
</FIGURE>

<PARA>Next, select the <EMPHASIS>Build-&#62;Library</EMPHASIS> menu
item to start building <productname>eCos</productname> (see <XREF
LINKEND="FIGURE-SELECTING-THE-BUILD-LIBRARY-MENU-ITEM">).  The
application will configure the sources, prepare a build tree, and
build the <FILENAME>libtarget.a</FILENAME> library, which contains the
<productname>eCos</productname> kernel and other packages.</PARA>

<FIGURE ID="FIGURE-SELECTING-THE-BUILD-LIBRARY-MENU-ITEM"><!-- <xref> -->
<TITLE>Selecting the Build Library menu item</TITLE>
<GRAPHIC ENTITYREF="programming-graphic4"></GRAPHIC>
</FIGURE>


<PARA>The <EMPHASIS>Save As</EMPHASIS> dialog box will appear, asking
you to specify a directory in which to place your save file. You
can use the default, but it is a good idea to make a subdirectory,
called <filename>ecos-work</filename> for example. </PARA>

<FIGURE>
<TITLE>Save file dialog</TITLE>
<GRAPHIC ENTITYREF="programming-graphic5"></GRAPHIC>
</FIGURE>

<PARA>The first time you build an <productname>eCos</productname> library for a specific
architecture, the <application>Configuration Tool</application> may prompt
you for the location of the appropriate build tools (including
<command>make</command> and
<command><replaceable>TARGET-</replaceable>gcc</command>) using a
<EMPHASIS>Build Tools</EMPHASIS> dialog box (as shown in <XREF
LINKEND="FIGURE-BUILD-TOOLS-DIALOG">). You can select a location from
the drop down list, browse to the directory using the
<EMPHASIS>Browse</EMPHASIS> button, or type in the location of the
build tools manually.</PARA>

<FIGURE ID="FIGURE-BUILD-TOOLS-DIALOG"><!-- <xref> -->
<TITLE>Build tools dialog</TITLE>
<GRAPHIC ENTITYREF="programming-graphic6"></GRAPHIC>
</FIGURE>

<PARA>The <application>Configuration Tool</application> may also prompt you
for the location of the user tools (such as <command>cat</command> and
<command>ls</command>) using a <emphasis>User Tools</emphasis> dialog
box (as shown in <XREF LINKEND="FIGURE-USER-TOOLS-DIALOG">). As with
the <EMPHASIS>Build Tools</EMPHASIS> dialog, you can select a location
from the drop down list, browse to the directory using the
<EMPHASIS>Browse</EMPHASIS> button, or type in the location of the
user tools manually. Note that on Linux, this will often be
unnecessary as the tools will already be on your PATH.</PARA>

<FIGURE ID="FIGURE-USER-TOOLS-DIALOG"><!-- <xref> -->
<TITLE>User tools dialog</TITLE>
<GRAPHIC ENTITYREF="programming-graphic7"></GRAPHIC>
</FIGURE>

<PARA>When the tool locations have been entered, the <application>Configuration
Tool</application> will configure the sources, prepare a build tree,
and build the <filename>libtarget.a</filename> library, which contains
the <productname>eCos</productname> kernel and other packages.</PARA>

<PARA>The output from the configuration process and the building
of <filename>libtarget.a</filename> will be shown in the output
window.</PARA>

<PARA>Once the build process has finished you will have a kernel
with other packages in <FILENAME>libtarget.a</FILENAME>. You should
now build the <productname>eCos</productname> tests for your particular configuration. </PARA>

<PARA>You can do this by selecting <EMPHASIS>Build</EMPHASIS> -&#62; <EMPHASIS>Tests</EMPHASIS>.
Notice that you could have selected <EMPHASIS>Tests</EMPHASIS> instead
of <EMPHASIS>Library</EMPHASIS> in the earlier step and it would
have built <EMPHASIS>both</EMPHASIS> the library and the tests,
but this would increase the build time substantially, and if you
do not need to build the tests it is unnecessary.</PARA>

<FIGURE>
<TITLE>Selecting the Build Tests menu item</TITLE>
<GRAPHIC ENTITYREF="programming-graphic8"></GRAPHIC>
</FIGURE>

<PARA><XREF LINKEND="RUNNING-AN-ECOS-TEST-CASE"> will guide you through running one
	    of the test cases you just built on the selected target,
	    using GDB. </PARA>
</SECT1>

<!-- ==================================================== -->

<SECT1 ID="USING-ECOSCONFIG-ON-LINUX">
<TITLE><!-- <index></index> -->
Ecosconfig on Windows and Linux Quick Start</TITLE>

<PARA>As an alternative to using the graphical
<application>Configuration Tool</application>, it is possible to
configure and build a kernel by editing a configuration file manually
and using the <command>ecosconfig</command> command. Users with a Unix
background may find this tool more suitable than the GUI tool
described in the previous section.</PARA>

<para>
Manual configuration and the <command>ecosconfig</command> command are
described in detail in <XREF LINKEND="manual-configuration">.
</para>

<para>
To use the <command>ecosconfig</command> command you need to start a
shell. In Windows you need to start a
<productname>CygWin</productname> <command>bash</command> shell, not a
DOS command line.
</para>

<!--
<para>
XXXXX Need to know whether there will be a packaged shell entry in the
start menu, and where XXXXX
</para>
-->

<PARA>The following instructions assume that the
<literal>PATH</literal> and <literal>ECOS_REPOSITORY</literal>
environment variables have been setup correctly as described in <XREF
LINKEND="user-guide-installation-linux">.  They also assume Linux
usage but equally well apply to Windows running Cygwin.</PARA>

<PARA>Before invoking <command>ecosconfig</command> you need to
choose a directory in which to work. For the purposes of this tutorial,
the default path will be <FILENAME><replaceable>BASE_DIR</replaceable>/ecos-work</FILENAME>.
Create this directory and change to it by typing: </PARA>

<PROGRAMLISTING>
$ mkdir <replaceable>BASE_DIR</replaceable>/ecos-work
$ cd <replaceable>BASE_DIR</replaceable>/ecos-work
</PROGRAMLISTING>

<PARA>To see what options can be used with <command>ecosconfig</command>,
type: </PARA>

<PROGRAMLISTING>$ ecosconfig --help</PROGRAMLISTING>

<PARA>The available packages, targets and templates may be listed
as follows:</PARA>

<PROGRAMLISTING>
$ ecosconfig list
</PROGRAMLISTING>

<PARA>Here is sample output from <command>ecosconfig</command> showing
the usage message.</PARA>

<EXAMPLE>
<TITLE>Getting <!-- <index></index> --> help from ecosconfig</TITLE>

<PROGRAMLISTING>
$ ecosconfig --help
Usage: ecosconfig [ qualifier ... ] [ command ]
  commands are:
    list                                       : list repository contents
    new TARGET [ TEMPLATE [ VERSION ] ]        : create a configuration
    target TARGET                              : change the target hardware
    template TEMPLATE [ VERSION ]              : change the template
    add PACKAGE [ PACKAGE ... ]                : add package(s)
    remove PACKAGE [ PACKAGE ... ]             : remove package(s)
    version VERSION PACKAGE [ PACKAGE ... ]    : change version of package(s)
    export FILE                                : export minimal config info
    import FILE                                : import additional config info
    check                                      : check the configuration
    resolve                                    : resolve conflicts
    tree                                       : create a build tree
  qualifiers are:
    --config=FILE                              : the configuration file
    --prefix=DIRECTORY                         : the install prefix
    --srcdir=DIRECTORY                         : the source repository
    --no-resolve                               : disable conflict
resolution
    --version                                  : show version and copyright
$
</PROGRAMLISTING>
</EXAMPLE>

<EXAMPLE>

<TITLE>ecosconfig output &mdash; <!-- <index></index> -->
list of available packages, targets and templates</TITLE>

<PROGRAMLISTING>
$ ecosconfig list
Package CYGPKG_CYGMON (CygMon support via eCos): 
aliases: cygmon 
versions: &Version; 
Package CYGPKG_DEVICES_WALLCLOCK_DALLAS_DS1742 (Wallclock driver for Dallas 1742): 
aliases: devices_wallclock_ds1742 device_wallclock_ds1742 
versions: &Version; 
Package CYGPKG_DEVICES_WALLCLOCK_SH3 (Wallclock driver for SH3 RTC module): 
aliases: devices_wallclock_sh3 device_wallclock_sh3 
versions: &Version; 
Package CYGPKG_DEVICES_WATCHDOG_ARM_AEB (Watchdog driver for ARM/AEB board): 
aliases: devices_watchdog_aeb device_watchdog_aeb 
versions: &Version; 
Package CYGPKG_DEVICES_WATCHDOG_ARM_EBSA285 (Watchdog driver for ARM/EBSA285 board): 
aliases: devices_watchdog_ebsa285 device_watchdog_ebsa285 
versions: &Version; 
&hellip;
</PROGRAMLISTING>
</EXAMPLE>


<SECT2>
<TITLE>Selecting a <!-- <index></index> --> Target</TITLE>

<PARA>To configure for a listed target, type: </PARA>

<PROGRAMLISTING>
$ ecosconfig new &lt;target&#62;
</PROGRAMLISTING>

<PARA>For example, to configure for the ARM PID development board,
type: </PARA>

<PROGRAMLISTING>
$ ecosconfig new pid
</PROGRAMLISTING>

<PARA>You can then edit the generated file,
<FILENAME>ecos.ecc</FILENAME>, setting the options as required for the
target (endianess, CPU model, Startup type, etc.).  For detailed
information about how to edit the <filename>ecos.ecc</filename> file,
see the <citetitle>CDL Writer's Guide</citetitle> and <XREF
LINKEND="editing-an-ecos-savefile">.
</PARA>

<PARA>Create a build tree for the configured target by typing:</PARA>

<PROGRAMLISTING>
$ ecosconfig tree
</PROGRAMLISTING>

<para>
If there are any problem with the configuration,
<command>ecosconfig</command> will tell you. The most likely cause of
this is mistakes when editing the <filename>ecos.ecc</filename> file.
You can check whether the configuration you have made is correct,
without building the tree with the following command:
</para>

<PROGRAMLISTING>
$ ecosconfig check
</PROGRAMLISTING>

<para>
If this reports any conflicts you can get
<command>ecosconfig</command> to try and resolve them itself by typing:
</para>

<PROGRAMLISTING>
$ ecosconfig resolve
</PROGRAMLISTING>

<para>
See <XREF LINKEND="conflicts-and-constraints"> for more details.
</para>

<PARA>You can now run the command <command>make</command> or <command>make
tests</command>, after which you will be at the same point you
would be after running the <application>Configuration Tool</application>
&mdash; you can start developing your own applications,
following the steps in <XREF LINKEND="BUILDING-AND-RUNNING-SAMPLE-APPLIATIONS">. </PARA>

<PARA>The procedure shown above allows you to do very coarse-grained
configuration of the <productname>eCos</productname> kernel: you can select which packages
to include in your kernel, and give target and start-up options.
But you cannot select components within a package, or set the very
fine-grained options. </PARA>

<PARA>To select fine-grained configuration options you will need to
edit the configuration file <filename>ecos.ecc</filename> in the
current directory and regenerate the build tree.</PARA>

<CAUTION>
<PARA>You should follow the manual configuration process described
above very carefully, and you should read the comments in each file
to see when one option depends on other options or packages being
enabled or disabled. If you do not, you might end up with an inconsistently
configured kernel which could fail to build or might execute
incorrectly.</PARA>
</CAUTION>

</SECT2>
</SECT1>

</CHAPTER>

<!-- ==================================================== -->

<CHAPTER ID="RUNNING-AN-ECOS-TEST-CASE">
<TITLE>Running an <productname>eCos</productname> Test Case</TITLE>

<PARA>In <XREF LINKEND="using-configtool-windows-linux"> or <XREF
LINKEND="using-ecosconfig-on-linux"> you created the <productname>eCos</productname> test cases
as part of the build process. Now it is time to try and run one.
</para>

<!-- ==================================================== -->

<SECT1 id="using-configtool-testcase">
<TITLE>Using the <application>Configuration Tool</application></TITLE>

<PARA>Test executables that have been linked using the
<emphasis>Build-&gt;Tests</emphasis> operation against the current
configuration can be executed by selecting <EMPHASIS>Tools-&#62;Run
Tests</EMPHASIS>.</PARA>

<PARA>When a test run is invoked, a property sheet is displayed, see
<xref linkend="programming-run-tests">. Press the <emphasis>Uncheck
All</emphasis> button and then find and check just one test,
<filename>bin_sem0</filename> for example.
</para>

<FIGURE id="programming-run-tests">
<TITLE>Run tests</TITLE>
<GRAPHIC ENTITYREF="graphic27"></GRAPHIC>
</FIGURE>

<para>
Now press the <emphasis>Properties</emphasis> button to set up
communications with the target. This will bring up a properties dialog
shown in <xref linkend="programming-run-properties">. If you have
connected the target board via a serial cable, check the
<emphasis>Serial</emphasis> radio button, and select the serial port
and baud rate for the board. If the target is connected via the
network select the <emphasis>TCP/IP</emphasis> button and enter the IP
address that the board has been given, and the port number (usually
9000).
</para>

<FIGURE id="programming-run-properties">
<TITLE>Properties dialog box</TITLE>
<GRAPHIC ENTITYREF="graphic25"></GRAPHIC>
</FIGURE>

<para>
Click OK on this dialog and go back to the <emphasis>Run
Tests</emphasis> dialog. Press the <emphasis>Run</emphasis> button and
the selected test will be downloaded and run. The
<emphasis>Output</emphasis> tab will show you how this is
progressing. If it seems to stop for a long time, check that the
target board is correctly connected, and that <productname>eCos</productname> has been correctly
configured -- especially the start-up type.
</para>

<para>
When the program runs you should see a couple of line similar to this appear:
</para>

<PROGRAMLISTING>
PASS:&lt;Binary Semaphore 0 OK&gt;
EXIT:&lt;done&gt;
</PROGRAMLISTING>

<para>
This indicates that the test has run successfully.
</para>

<PARA>See <xref linkend="config-tool-test-execution"> for
further details.</PARA>

</SECT1>

<!-- ==================================================== -->

<SECT1 id="using-commandline-testcase">
<TITLE>Using the command line</TITLE>

<PARA>Start a command shell (such as a Cygwin shell window in Windows)
with the environment variables set as described in the toolchain
documentation.  Change to the directory in which you set up your build
tree, and invoke <!-- <index></index> --> GDB on the test
program.</PARA>

<PARA>To run the <!-- <index></index> -->bin_sem0 test (which will
test the kernel for the correct creation and destruction of binary
semaphores) type: </PARA>

<PROGRAMLISTING>
$ <replaceable>TARGET-</replaceable>gdb -nw install/tests/kernel/<replaceable>&Version;</replaceable>/tests/bin_sem0
</PROGRAMLISTING>

<PARA>You should see output similar to the following in the command
window:</PARA>

<PROGRAMLISTING>
GNU gdb THIS-GDB-VERSION
Copyright 2001 Free Software Foundation, Inc.
GDB is free software, covered by the GNU General Public License, and you are
welcome to change it and/or distribute copies of it under certain conditions.
Type "show copying" to see the conditions.
There is absolutely no warranty for GDB.  Type "show warranty" for details.
This GDB was configured as "--host=THIS-HOST --target=THIS-TARGET".
(gdb)
</PROGRAMLISTING>

<PARA>If you are trying to run a synthetic target test on <!--
<index></index> -->Linux, skip the following connection and download
steps. Otherwise, connect to the target by typing: </PARA>

<PROGRAMLISTING>
(gdb) set remotebaud 38400
(gdb) target remote /dev/ttyS0
</PROGRAMLISTING>
<PARA>on Linux or</PARA>
<PROGRAMLISTING>
(gdb) set remotebaud 38400
(gdb) target remote com1
</PROGRAMLISTING>
<PARA>on Windows or</PARA>
<PROGRAMLISTING>
(gdb) target sim
</PROGRAMLISTING>
<para>to use a simulator in either host O/S.</para>

<para>
Check the documentation for the target board for the actual baud rate
to use when connecting to real targets.
</para>

<PARA>
You will see output similar to the following: </PARA>

<programlisting width=72>
Remote debugging using /dev/ttyS1
0x0000d50c in ?? ()
    at <replaceable>BASE_DIR</replaceable>/kernel/<replaceable>&Version;</replaceable>/src/common/kapi.cxx:345

Current language:  auto; currently c++
(gdb) 
</programlisting>

<para>
Or if you are using the simulator:
</para>

<PROGRAMLISTING>
Connected to the simulator.
(gdb)
</PROGRAMLISTING>

<PARA>Now download the program to the target with</PARA>

<PROGRAMLISTING>
(gdb) load
</PROGRAMLISTING>

<PARA>You should see output similar to the following on your screen: </PARA>

<PROGRAMLISTING>
Loading section .text, size 0x4b04 lma 0x108000
Loading section .rodata, size 0x738 lma 0x10cb08
Loading section .data, size 0x1c0 lma 0x10d240
Start address 0x108000, load size 21500
Transfer rate: 24571 bits/sec, 311 bytes/write.
(gdb)
</PROGRAMLISTING>

<PARA>You are now ready to run your program. If you type: </PARA>

<PROGRAMLISTING>
(gdb) continue
</PROGRAMLISTING>

<PARA>you will see output similar to the following: </PARA>

<PROGRAMLISTING>
Continuing.
PASS:&lt;Binary Semaphore 0 OK&gt;
EXIT:&lt;done&gt;
</PROGRAMLISTING>

<NOTE>
<PARA> If you are using a simulator or the synthetic target rather
	    than real hardware, you must use the GDB command
	    &ldquo;run&rdquo; rather than &ldquo;continue&rdquo; to
	    start your program.</PARA>
</NOTE>

<PARA>You can terminate your GDB session with
<EMPHASIS>Control+C</EMPHASIS>, otherwise it will sit in the
&ldquo;idle&rdquo; thread and use up CPU time. This is not a problem
with real targets, but may have undesirable effects in simulated or
synthetic targets. Type <command>quit</command> and you are
done. </PARA>

</SECT1>

<!-- ==================================================== -->

<SECT1 id="testing-filters">
<TITLE>Testing Filters</TITLE>

<PARA>While most test cases today run solely in the target environment,
some packages may require external testing infrastructure and/or
feedback from the external environment to do complete testing.</PARA>

<PARA>The serial package is an example of this. The network package
also contains some tests that require programs to be run on a
host. See the network <citetitle>Tests and Demonstrations</citetitle>
section in the network documentation in the <citetitle><productname>eCos</productname> Reference
Guide</citetitle>. Here we will concentrate on the serial tests since
these are applicable to more targets.
</para>

<PARA>Since the serial line is also used for communication with
GDB, a  filter is inserted in the communication pathway between
GDB and the serial device which is connected to the hardware target.
The filter forwards all communication between the two, but also
listens for special commands embedded in the data stream from the
target.</PARA>

<PARA>When such a command is seen, the filter stops forwarding data
to GDB from the target and enters a special mode. In this mode
the test case running on the target is able to control the filter,
commanding it to run various tests. While these tests run, GDB is
isolated from the target.</PARA>

<PARA>As the test completes (or if the filter detects a target crash)
the communication path between GDB and the hardware target is re-established,
allowing GDB to resume control.</PARA>

<PARA>In theory, it is possible to extend the filter to provide
a generic framework for other target-external testing components,
thus decoupling the testing infrastructure from the (possibly limited)
communication means provided by the target (serial, JTAG, Ethernet,
etc). </PARA>

<PARA>Another advantage is that the host tools do not need to
know about the various testing environments required by the <productname>eCos</productname>
packages, since all contact with the target continues to happen
via GDB.</PARA>

</sect1>

</CHAPTER>


<!-- ==================================================== -->

<CHAPTER ID="BUILDING-AND-RUNNING-SAMPLE-APPLIATIONS"><!-- <conditionaltext> -->
<TITLE><!-- <xref> -->Building and <!-- <index></index> -->Running Sample Applications</TITLE>

<PARA>The example programs in this tutorial are included, along
with a <filename>Makefile</filename>, in the <filename>examples</filename> directory
of the <productname>eCos</productname> distribution. The first program you will run is a <EMPHASIS>hello
world</EMPHASIS>-style application, then you will run a more complex
application that demonstrates the creation of threads and the use
of cyg_thread_delay(), and finally you will run
one that uses clocks and alarm handlers.</PARA>

<PARA>The <filename>Makefile</filename> depends on an externally
defined variable to find the <productname>eCos</productname> library and header files. This
variable is <literal>INSTALL_DIR</literal> and must be set to the
pathname of the install directory created in <xref
linkend="using-configtool-windows-linux">.
</PARA>

<para>
<literal>INSTALL_DIR</literal> may be either be set in the shell
environment or may be supplied on the command line. To set it in the
shell do the following in a <command>bash</command> shell:
</para>

<programlisting width=72>
$ export INSTALL_DIR=BASE_DIR/ecos-work/arm_install
</programlisting>

<para>
You can then run <command>make</command> without any extra parameters
to build the examples.
</para>

<para>
Alternatively, if you can do the following:
</para>

<programlisting width=72>
$ make INSTALL_DIR=BASE_DIR/ecos-work/arm_install
</programlisting>

<!-- ==================================================== -->

<SECT1 id="ecos-hello-world">
<TITLE><productname>eCos</productname> Hello World</TITLE>

<PARA>The following code is found in the file <FILENAME><!-- <index></index> -->hello.c</FILENAME>
in the <FILENAME>examples</FILENAME> directory: </PARA>

<SECT2>
<TITLE><productname>eCos</productname><!-- <index></index> --> hello world program listing</TITLE>

<PROGRAMLISTING>
/* this is a simple hello world program */
#include &lt;stdio.h&#62;
int main(void)
{
 printf("Hello, eCos world!\n");
 return 0;
}
</PROGRAMLISTING>

<PARA>To compile this or any other program that is not part of the
<productname>eCos</productname> distribution, you can follow the procedures described below. Type
this explicit compilation command (assuming your current working
directory is also where you built the <productname>eCos</productname> kernel):</PARA>

<PROGRAMLISTING>
$ <replaceable>TARGET-</replaceable>gcc -g -I<replaceable>BASE_DIR</replaceable>/ecos-work/install/include hello.c -L<replaceable>BASE_DIR</replaceable>/ecos-work/install/lib -Ttarget.ld -nostdlib
</PROGRAMLISTING>

<PARA>The compilation command above contains some standard GCC
options (for example, <OPTION>-g</OPTION> enables debugging), as well
as some mention of paths
(<OPTION>-I<replaceable>BASE_DIR</replaceable>/ecos-work/install/include</OPTION> allows files
like <FILENAME>cyg/kernel/kapi.h</FILENAME> to be found, and
<OPTION>-L<replaceable>BASE_DIR</replaceable>/ecos-work/install/lib</OPTION> allows the linker to
find <OPTION>-Ttarget.ld</OPTION>). </PARA>

<PARA>The executable program will be called <FILENAME>a.out</FILENAME>. </PARA>

<NOTE>
<PARA>Some target systems require special options to be passed to
gcc to compile correctly for that system. Please examine the Makefile
in the examples directory to see if this applies to your target.</PARA>
</NOTE>

<PARA>You can now run the resulting program using GDB in exactly the
same the way you ran the test case before. The procedure will be the
same, but this time run
<command><replaceable>TARGET-</replaceable>gdb</command> specifying
<option>-nw a.out</option> on the command line:</PARA>

<PROGRAMLISTING>
$ <replaceable>TARGET-</replaceable>gdb -nw a.out
</PROGRAMLISTING>

<PARA>For targets other than the synthetic linux target, you should
now run the usual GDB commands described earlier. Once this is done,
typing the command "continue" at the (gdb) prompt ("run" for
simulators) will allow the program to execute and print the string
"Hello, eCos world!" on your screen.</PARA>

<PARA>On the synthetic linux target, you may use the "run" command
immediately - you do not need to connect to the target, nor use the
"load" command.<!-- <conditionaltext> --></PARA>

</SECT2>
</SECT1>

<!-- ==================================================== -->

<SECT1 id="sample-twothreads">
<TITLE>A Sample Program with Two Threads</TITLE>

<PARA>Below is a program that uses some of <productname>eCos</productname>' system calls. It
creates two threads, each of which goes into an infinite loop in which
it sleeps for a while (using cyg_thread_delay()).  This code is found
in the file <filename><!-- <index></index> -->twothreads.c</filename>
in the examples directory.</PARA>

<SECT2>
<TITLE><productname>eCos</productname> <!-- <index></index> -->two-threaded program listing</TITLE>

<PROGRAMLISTING>
#include &lt;cyg/kernel/kapi.h&#62;
#include &lt;stdio.h&#62;
#include &lt;math.h&#62;
#include &lt;stdlib.h&#62;

/* now declare (and allocate space for) some kernel objects,
  like the two threads we will use */
cyg_thread thread_s[2];	/* space for two thread objects */

char stack[2][4096];	/* space for two 4K stacks */

/* now the handles for the threads */
cyg_handle_t simple_threadA, simple_threadB;

/* and now variables for the procedure which is the thread */
cyg_thread_entry_t simple_program;

/* and now a mutex to protect calls to the C library */
cyg_mutex_t cliblock;

/* we install our own startup routine which sets up threads */
void cyg_user_start(void)
{
 printf("Entering twothreads' cyg_user_start() function\n");

 cyg_mutex_init(&amp;cliblock);

 cyg_thread_create(4, simple_program, (cyg_addrword_t) 0,
	"Thread A", (void *) stack[0], 4096,
	&amp;simple_threadA, &amp;thread_s[0]);
 cyg_thread_create(4, simple_program, (cyg_addrword_t) 1,
	"Thread B", (void *) stack[1], 4096,
	&amp;simple_threadB, &amp;thread_s[1]);

 cyg_thread_resume(simple_threadA);
 cyg_thread_resume(simple_threadB);
}

/* this is a simple program which runs in a thread */
void simple_program(cyg_addrword_t data)
{
 int message = (int) data;
 int delay;

 printf("Beginning execution; thread data is %d\n", message);

 cyg_thread_delay(200);

 for (;;) {
 delay = 200 + (rand() % 50);

 /* note: printf() must be protected by a
 call to cyg_mutex_lock() */
 cyg_mutex_lock(&amp;cliblock); {
 printf("Thread %d: and now a delay of %d clock ticks\n",
	message, delay);
 }
 cyg_mutex_unlock(&amp;cliblock);
 cyg_thread_delay(delay);
 }
}
</PROGRAMLISTING>

<PARA>
When you run the program (by typing <command>continue</command> at
the (<EMPHASIS>gdb</EMPHASIS>) prompt) the output should look like
this:</PARA>

<PROGRAMLISTING>
Starting program: <replaceable>BASE_DIR</replaceable>/examples/twothreads.exe
Entering twothreads' cyg_user_start()
function
Beginning execution; thread data is 0
Beginning execution; thread data is 1
Thread 0: and now a delay of 240 clock ticks
Thread 1: and now a delay of 225 clock ticks
Thread 1: and now a delay of 234 clock ticks
Thread 0: and now a delay of 231 clock ticks
Thread 1: and now a delay of 224 clock ticks
Thread 0: and now a delay of 249 clock ticks
Thread 1: and now a delay of 202 clock ticks
Thread 0: and now a delay of 235 clock ticks
</PROGRAMLISTING>

<NOTE>
<PARA>When running in a simulator the <!-- <index></index> -->
delays might be quite long. On a hardware board (where the clock
speed is 100 ticks/second) the delays should average to
about 2.25 seconds. In simulation, the delay will depend on the
speed of the host processor and will almost always be much slower than
the actual board. You might want to reduce the delay parameter when running
in simulation.
</PARA>
</NOTE>

<PARA>
<XREF LINKEND="FIGURE-TWOTHREADS-WITH-SIMPLE-PRINTS"> shows how this
multitasking program executes.  Note that apart from the thread
creation system calls, this program also creates and uses a
<EMPHASIS><!-- <index></index> -->mutex</EMPHASIS> for synchronization
between the <function>printf()</function> calls in the two
threads. This is because the C library standard I/O (by default) is
configured not to be thread-safe, which means that if more than one
thread is using standard I/O they might corrupt each other. This is
fixed by a mutual exclusion (or <EMPHASIS>mutex</EMPHASIS>) lockout
mechanism: the threads do not call <function>printf()</function> until
<function>cyg_mutex_lock()</function> has returned, which only happens
when the other thread calls
<function>cyg_mutex_unlock()</function>.</PARA>

<PARA>You could avoid using the mutex by configuring the C library to
be thread-safe (by selecting the component
<LITERAL>CYGSEM_LIBC_STDIO_THREAD_SAFE_STREAMS</LITERAL>).</PARA>

<FIGURE
ID="FIGURE-TWOTHREADS-WITH-SIMPLE-PRINTS"><!-- <xref> --> <TITLE>Two
threads with simple print statements after random delays</TITLE>
<GRAPHIC ENTITYREF="programming-graphic9"></GRAPHIC>
</FIGURE>

</SECT2>

</SECT1>

</CHAPTER>

<!-- ==================================================== -->

<CHAPTER ID="CLOCKS-AND-ALARM-HANDLERS">
<TITLE>More Features &mdash; <!-- <index></index> -->Clocks and Alarm
Handlers</TITLE>

<PARA>If a program wanted to execute a task at a given time, or
periodically, it could do it in an inefficient way by sitting in a
loop and checking the real-time clock to see if the proper amount of
time has elapsed. But operating systems usually provide system calls
which allow the program to be informed at the desired time.</PARA>

<PARA><productname>eCos</productname> provides a rich timekeeping formalism, involving
<EMPHASIS>counters</EMPHASIS>, <EMPHASIS>clocks</EMPHASIS>,
<EMPHASIS>alarms</EMPHASIS>, and <EMPHASIS>timers</EMPHASIS>.  The
precise definition, relationship, and motivation of these features is
beyond the scope of this tutorial, but these examples illustrate how
to set up basic periodic tasks.</PARA>

<PARA><!-- <index></index> -->Alarms are events that happen at
a given time, either once or periodically. A thread associates an
alarm handling function with the alarm, so that the function will
be invoked every time the alarm &ldquo;goes off&rdquo;.</PARA>

<!-- ==================================================== -->

<SECT1 id="sample-alarms">
<TITLE>A Sample Program with Alarms</TITLE>

<PARA><!-- <index></index> --><FILENAME>simple-alarm.c</FILENAME> (in
the examples directory) is a short program that creates a thread that
creates an alarm. The alarm is handled by the function
<FUNCTION>test_alarm_func()</FUNCTION>, which sets a global
variable. When the main thread of execution sees that the variable has
changed, it prints a message.</PARA>

<EXAMPLE>
<TITLE>A sample <!-- <index></index> -->program that creates an alarm</TITLE>

<PROGRAMLISTING>
/* this is a very simple program meant to demonstrate
 a basic use of time, alarms and alarm-handling functions  in eCos */

#include &lt;cyg/kernel/kapi.h&#62;

#include &lt;stdio.h&#62;

#define NTHREADS 1
#define STACKSIZE 4096

static cyg_handle_t thread[NTHREADS];

static cyg_thread thread_obj[NTHREADS];
static char stack[NTHREADS][STACKSIZE];

static void alarm_prog( cyg_addrword_t data );

/* we install our own startup routine which sets up
  threads and starts the scheduler */
void cyg_user_start(void)
{
 cyg_thread_create(4, alarm_prog, (cyg_addrword_t) 0,
	"alarm_thread", (void *) stack[0],
	STACKSIZE, &amp;thread[0], &amp;thread_obj[0]);
 cyg_thread_resume(thread[0]);
}

/* we need to declare the alarm handling function (which is
 defined below), so that we can pass it to  cyg_alarm_initialize() */
cyg_alarm_t test_alarm_func;

/* alarm_prog() is a thread which sets up an alarm which is then
 handled by test_alarm_func() */
static void alarm_prog(cyg_addrword_t data)
{
 cyg_handle_t test_counterH, system_clockH, test_alarmH;
 cyg_tick_count_t ticks;
 cyg_alarm test_alarm;
 unsigned how_many_alarms = 0, prev_alarms = 0, tmp_how_many;

 system_clockH = cyg_real_time_clock();
 cyg_clock_to_counter(system_clockH, &amp;test_counterH);
 cyg_alarm_create(test_counterH, test_alarm_func,
	(cyg_addrword_t) &amp;how_many_alarms,
	&amp;test_alarmH, &amp;test_alarm);
 cyg_alarm_initialize(test_alarmH, cyg_current_time()+200, 200);

 /* get in a loop in which we read the current time and
    print it out, just to have something scrolling by */
 for (;;) {
   ticks = cyg_current_time();
   printf("Time is %llu\n", ticks);
   /* note that we must lock access to how_many_alarms, since the
   alarm handler might change it. this involves using the
   annoying temporary variable tmp_how_many so that I can keep the
   critical region short */
   cyg_scheduler_lock();
   tmp_how_many = how_many_alarms;
   cyg_scheduler_unlock();
   if (prev_alarms != tmp_how_many) {
     printf(" --- alarm calls so far: %u\n", tmp_how_many);
     prev_alarms = tmp_how_many;
   }
   cyg_thread_delay(30);
 }
}

/* test_alarm_func() is invoked as an alarm handler, so
   it should be quick and simple. in this case it increments
   the data that is passed to it. */
void test_alarm_func(cyg_handle_t alarmH, cyg_addrword_t data)
{
 ++*((unsigned *) data);
}
</PROGRAMLISTING>
</EXAMPLE>

<PARA>When you run this program (by typing <COMMAND>continue</COMMAND> at
the (<EMPHASIS>gdb</EMPHASIS>) prompt) the output should look like
this:</PARA>
<SCREEN>
Starting program: <replaceable>BASE_DIR</replaceable>/examples/simple-alarm.exe
Time is 0
Time is 30
Time is 60
Time is 90
Time is 120
Time is 150
Time is 180
Time is 210
  --- alarm calls so far: 1
Time is 240
Time is 270
Time is 300
Time is 330
Time is 360
Time is 390
Time is 420
  --- alarm calls so far: 2
Time is 450
Time is 480
</SCREEN>

<NOTE>
<PARA>When running in a simulator the <!-- <index></index> --> delays
might be quite long. On a hardware board (where the clock speed is 100
ticks/second) the delays should average to about 0.3 seconds (and 2
seconds between alarms). In simulation, the delay will depend on the
speed of the host processor and will almost always be much slower than
the actual board. You might want to reduce the delay parameter when
running in simulation.</PARA>
</NOTE>

<PARA>Here are a few things you might notice about this program:</PARA>

<ITEMIZEDLIST>
<LISTITEM>
<PARA>It used the <function>cyg_real_time_clock()</function> function;
this always returns a handle to the default system real-time <!--
<index></index> --> clock. </PARA>
</LISTITEM>

<LISTITEM>
<PARA><!-- <index></index> -->Clocks are based on <!-- <index></index>
--> counters, so the function <function>cyg_alarm_create()</function>
uses a counter handle. The program used the function
<function>cyg_clock_to_counter()</function> to strip the clock handle
to the underlying counter handle. </PARA>
</LISTITEM>

<LISTITEM>
<PARA>Once the alarm is created it is <!-- <index></index> -->
initialized with <function>cyg_alarm_initialize()</function>, which
sets the time at which the alarm should go off, as well as the period
for repeating alarms. It is set to go off at the current time and
then to repeat every 200 ticks. </PARA>
</LISTITEM>

<LISTITEM>
<PARA>The alarm handler function
<function>test_alarm_func()</function> conforms to the guidelines for
writing alarm handlers and other <!-- <index></index> --><!--
<index></index> --> delayed service routines: it does not invoke any
functions which might lock the scheduler.  This is discussed in detail
in the <CITETITLE><productname>eCos</productname> Reference Manual</CITETITLE>, in the chapter
<citetitle>The <productname>eCos</productname> Kernel</citetitle>.</PARA>
</LISTITEM>

<LISTITEM>
<PARA>There is a <EMPHASIS>critical region</EMPHASIS> in this program:
the variable <LITERAL>how_many_alarms</LITERAL> is accessed in the
main thread of control and is also modified in the alarm handler. To
prevent a possible (though unlikely) race condition on this variable,
access to <LITERAL>how_many_alarms</LITERAL> in the principal thread
is protected by calls to <FUNCTION>cyg_scheduler_lock()</FUNCTION> and
<FUNCTION>cyg_scheduler_unlock()</FUNCTION>. When the scheduler is
locked, the alarm handler will not be invoked, so the problem is
averted. </PARA>
</LISTITEM>
</ITEMIZEDLIST>
</SECT1>
</CHAPTER>

</part>