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<h3 class="section">17.2 Continuing at a Different Address</h3>

<p>Ordinarily, when you continue your program, you do so at the place where
it stopped, with the <code>continue</code> command.  You can instead continue at
an address of your own choosing, with the following commands:

     
<a name="index-jump-928"></a>
<dl><dt><code>jump </code><var>linespec</var><dt><code>jump </code><var>location</var><dd>Resume execution at line <var>linespec</var> or at address given by
<var>location</var>.  Execution stops again immediately if there is a
breakpoint there.  See <a href="Specify-Location.html#Specify-Location">Specify Location</a>, for a description of the
different forms of <var>linespec</var> and <var>location</var>.  It is common
practice to use the <code>tbreak</code> command in conjunction with
<code>jump</code>.  See <a href="Set-Breaks.html#Set-Breaks">Setting Breakpoints</a>.

     <p>The <code>jump</code> command does not change the current stack frame, or
the stack pointer, or the contents of any memory location or any
register other than the program counter.  If line <var>linespec</var> is in
a different function from the one currently executing, the results may
be bizarre if the two functions expect different patterns of arguments or
of local variables.  For this reason, the <code>jump</code> command requests
confirmation if the specified line is not in the function currently
executing.  However, even bizarre results are predictable if you are
well acquainted with the machine-language code of your program. 
</dl>

<!-- Doesn't work on HP-UX; have to set $pcoqh and $pcoqt. -->
   <p>On many systems, you can get much the same effect as the <code>jump</code>
command by storing a new value into the register <code>$pc</code>.  The
difference is that this does not start your program running; it only
changes the address of where it <em>will</em> run when you continue.  For
example,

<pre class="smallexample">     set $pc = 0x485
</pre>
   <p class="noindent">makes the next <code>continue</code> command or stepping command execute at
address <code>0x485</code>, rather than at the address where your program stopped. 
See <a href="Continuing-and-Stepping.html#Continuing-and-Stepping">Continuing and Stepping</a>.

   <p>The most common occasion to use the <code>jump</code> command is to back
up&mdash;perhaps with more breakpoints set&mdash;over a portion of a program
that has already executed, in order to examine its execution in more
detail.

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