toolchain/gcc-linaro-6.3.1-2017.02-x8.../share/doc/ld.html/Entry-Point.html

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<a name="Setting-the-Entry-Point"></a>
<h4 class="subsection">3.4.1 Setting the Entry Point</h4>
<a name="index-ENTRY_0028symbol_0029"></a>
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<p>The first instruction to execute in a program is called the <em>entry
point</em>. You can use the <code>ENTRY</code> linker script command to set the
entry point. The argument is a symbol name:
</p><div class="smallexample">
<pre class="smallexample">ENTRY(<var>symbol</var>)
</pre></div>
<p>There are several ways to set the entry point. The linker will set the
entry point by trying each of the following methods in order, and
stopping when one of them succeeds:
</p><ul>
<li> the &lsquo;<samp>-e</samp>&rsquo; <var>entry</var> command-line option;
</li><li> the <code>ENTRY(<var>symbol</var>)</code> command in a linker script;
</li><li> the value of a target specific symbol, if it is defined; For many
targets this is <code>start</code>, but PE and BeOS based systems for example
check a list of possible entry symbols, matching the first one found.
</li><li> the address of the first byte of the &lsquo;<samp>.text</samp>&rsquo; section, if present;
</li><li> The address <code>0</code>.
</li></ul>
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