</p>

<h3 id="Letters_and_digits">Letters and digits</h3>

<p>
The underscore character <code>_</code> (U+005F) is considered a letter.
</p>
<pre class="ebnf">
letter        = unicode_letter | "_" .
decimal_digit = "0" … "9" .
binary_digit  = "0" | "1" .
octal_digit   = "0" … "7" .
hex_digit     = "0" … "9" | "A" … "F" | "a" … "f" .
</pre>

</p>

<h3 id="Letters_and_digits">Letters and digits</h3>

<p>
The underscore character <code>_</code> (U+005F) is considered a lowercase letter.
</p>
<pre class="ebnf">
letter        = unicode_letter | "_" .
decimal_digit = "0" … "9" .
binary_digit  = "0" | "1" .
octal_digit   = "0" … "7" .
hex_digit     = "0" … "9" | "A" … "F" | "a" … "f" .
</pre>

<p>
The name <code>SP</code> always refers to the virtual stack pointer described earlier.
For the hardware register, use <code>R13</code>.
</p>

<p>
Condition code syntax is to append a period and the one- or two-letter code to the instruction,
as in <code>MOVW.EQ</code>.
Multiple codes may be appended: <code>MOVM.IA.W</code>.
The order of the code modifiers is irrelevant.
</p>

<p>
Addressing modes:
</p>

<ul>