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<h4 class="subsection">3.5.1 Simple Assignments</h4>
<p>You may assign to a symbol using any of the C assignment operators:
<dl>
<dt><var>symbol</var><code> = </code><var>expression</var><code> ;</code><dt><var>symbol</var><code> += </code><var>expression</var><code> ;</code><dt><var>symbol</var><code> -= </code><var>expression</var><code> ;</code><dt><var>symbol</var><code> *= </code><var>expression</var><code> ;</code><dt><var>symbol</var><code> /= </code><var>expression</var><code> ;</code><dt><var>symbol</var><code> <<= </code><var>expression</var><code> ;</code><dt><var>symbol</var><code> >>= </code><var>expression</var><code> ;</code><dt><var>symbol</var><code> &= </code><var>expression</var><code> ;</code><dt><var>symbol</var><code> |= </code><var>expression</var><code> ;</code><dd></dl>
<p>The first case will define <var>symbol</var> to the value of
<var>expression</var>. In the other cases, <var>symbol</var> must already be
defined, and the value will be adjusted accordingly.
<p>The special symbol name ‘<samp><span class="samp">.</span></samp>’ indicates the location counter. You
may only use this within a <code>SECTIONS</code> command. See <a href="Location-Counter.html#Location-Counter">Location Counter</a>.
<p>The semicolon after <var>expression</var> is required.
<p>Expressions are defined below; see <a href="Expressions.html#Expressions">Expressions</a>.
<p>You may write symbol assignments as commands in their own right, or as
statements within a <code>SECTIONS</code> command, or as part of an output
section description in a <code>SECTIONS</code> command.
<p>The section of the symbol will be set from the section of the
expression; for more information, see <a href="Expression-Section.html#Expression-Section">Expression Section</a>.
<p>Here is an example showing the three different places that symbol
assignments may be used:
<pre class="smallexample"> floating_point = 0;
SECTIONS
{
.text :
{
*(.text)
_etext = .;
}
_bdata = (. + 3) & ~ 3;
.data : { *(.data) }
}
</pre>
<p class="noindent">In this example, the symbol ‘<samp><span class="samp">floating_point</span></samp>’ will be defined as
zero. The symbol ‘<samp><span class="samp">_etext</span></samp>’ will be defined as the address following
the last ‘<samp><span class="samp">.text</span></samp>’ input section. The symbol ‘<samp><span class="samp">_bdata</span></samp>’ will be
defined as the address following the ‘<samp><span class="samp">.text</span></samp>’ output section aligned
upward to a 4 byte boundary.
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