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<a name="Putting-it-All-Together"></a>
<h4 class="subsection">20.5.3 Putting it All Together</h4>

<a name="index-remote-serial-debugging-summary"></a>
<p>In summary, when your program is ready to debug, you must follow these
steps.
</p>
<ol>
<li> Make sure you have defined the supporting low-level routines
(see <a href="Bootstrapping.html#Bootstrapping">What You Must Do for the Stub</a>):
<div class="display">
<pre class="display"><code>getDebugChar</code>, <code>putDebugChar</code>,
<code>flush_i_cache</code>, <code>memset</code>, <code>exceptionHandler</code>.
</pre></div>

</li><li> Insert these lines in your program&rsquo;s startup code, before the main
procedure is called:

<div class="smallexample">
<pre class="smallexample">set_debug_traps();
breakpoint();
</pre></div>

<p>On some machines, when a breakpoint trap is raised, the hardware
automatically makes the PC point to the instruction after the
breakpoint.  If your machine doesn&rsquo;t do that, you may need to adjust
<code>handle_exception</code> to arrange for it to return to the instruction
after the breakpoint on this first invocation, so that your program
doesn&rsquo;t keep hitting the initial breakpoint instead of making
progress.
</p>
</li><li> For the 680x0 stub only, you need to provide a variable called
<code>exceptionHook</code>.  Normally you just use:

<div class="smallexample">
<pre class="smallexample">void (*exceptionHook)() = 0;
</pre></div>

<p>but if before calling <code>set_debug_traps</code>, you set it to point to a
function in your program, that function is called when
<code><small>GDB</small></code> continues after stopping on a trap (for example, bus
error).  The function indicated by <code>exceptionHook</code> is called with
one parameter: an <code>int</code> which is the exception number.
</p>
</li><li> Compile and link together: your program, the <small>GDB</small> debugging stub for
your target architecture, and the supporting subroutines.

</li><li> Make sure you have a serial connection between your target machine and
the <small>GDB</small> host, and identify the serial port on the host.

</li><li> Download your program to your target machine (or get it there by
whatever means the manufacturer provides), and start it.

</li><li> Start <small>GDB</small> on the host, and connect to the target
(see <a href="Connecting.html#Connecting">Connecting to a Remote Target</a>).

</li></ol>

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