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<h5 class="subsubsection">9.3.2.1 Special Characters</h5>
<dl>
<dt><code>%</code><dd><a name="index-register-name-prefix-character_002c-ARC-604"></a><a name="index-ARC-register-name-prefix-character-605"></a>A register name can optionally be prefixed by a ‘<samp><span class="samp">%</span></samp>’ character. So
register <code>%r0</code> is equivalent to <code>r0</code> in the assembly code.
<br><dt><code>#</code><dd><a name="index-line-comment-character_002c-ARC-606"></a><a name="index-ARC-line-comment-character-607"></a>The presence of a ‘<samp><span class="samp">#</span></samp>’ character within a line (but not at the
start of a line) indicates the start of a comment that extends to the
end of the current line.
<p><em>Note:</em> if a line starts with a ‘<samp><span class="samp">#</span></samp>’ character then it can
also be a logical line number directive (see <a href="Comments.html#Comments">Comments</a>) or a
preprocessor control command (see <a href="Preprocessing.html#Preprocessing">Preprocessing</a>).
<br><dt><code>@</code><dd><a name="index-symbol-prefix-character_002c-ARC-608"></a><a name="index-ARC-symbol-prefix-character-609"></a>Prefixing an operand with an ‘<samp><span class="samp">@</span></samp>’ specifies that the operand is a
symbol and not a register. This is how the assembler disambiguates
the use of an ARC register name as a symbol. So the instruction
<pre class="example"> mov r0, @r0
</pre>
<p>moves the address of symbol <code>r0</code> into register <code>r0</code>.
<br><dt><code>`</code><dd><a name="index-line-separator_002c-ARC-610"></a><a name="index-statement-separator_002c-ARC-611"></a><a name="index-ARC-line-separator-612"></a>The ‘<samp><span class="samp">`</span></samp>’ (backtick) character is used to separate statements on a
single line.
<p><a name="index-line-613"></a><br><dt><code>-</code><dd><a name="index-C-preprocessor-macro-separator_002c-ARC-614"></a><a name="index-ARC-C-preprocessor-macro-separator-615"></a>Used as a separator to obtain a sequence of commands from a C
preprocessor macro.
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