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<h5 class="subsubsection">9.35.3.5 Size Translations</h5>

<p><a name="index-Sparc-size-translations-1649"></a><a name="index-size_002c-translations_002c-Sparc-1650"></a>
Often it is desirable to write code in an operand size agnostic
manner.  <code>as</code> provides support for this via
operand size opcode translations.  Translations are supported
for loads, stores, shifts, compare-and-swap atomics, and the
&lsquo;<samp><span class="samp">clr</span></samp>&rsquo; synthetic instruction.

   <p>If generating 32-bit code, <code>as</code> will generate the
32-bit opcode.  Whereas if 64-bit code is being generated,
the 64-bit opcode will be emitted.  For example <code>ldn</code>
will be transformed into <code>ld</code> for 32-bit code and
<code>ldx</code> for 64-bit code.

   <p>Here is an example meant to demonstrate all the supported
opcode translations:

<pre class="example">     ldn   [%o0], %o1
     ldna  [%o0] %asi, %o2
     stn   %o1, [%o0]
     stna  %o2, [%o0] %asi
     slln  %o3, 3, %o3
     srln  %o4, 8, %o4
     sran  %o5, 12, %o5
     casn  [%o0], %o1, %o2
     casna [%o0] %asi, %o1, %o2
     clrn  %g1
</pre>
   <p>In 32-bit mode <code>as</code> will emit:

<pre class="example">     ld   [%o0], %o1
     lda  [%o0] %asi, %o2
     st   %o1, [%o0]
     sta  %o2, [%o0] %asi
     sll  %o3, 3, %o3
     srl  %o4, 8, %o4
     sra  %o5, 12, %o5
     cas  [%o0], %o1, %o2
     casa [%o0] %asi, %o1, %o2
     clr  %g1
</pre>
   <p>And in 64-bit mode <code>as</code> will emit:

<pre class="example">     ldx   [%o0], %o1
     ldxa  [%o0] %asi, %o2
     stx   %o1, [%o0]
     stxa  %o2, [%o0] %asi
     sllx  %o3, 3, %o3
     srlx  %o4, 8, %o4
     srax  %o5, 12, %o5
     casx  [%o0], %o1, %o2
     casxa [%o0] %asi, %o1, %o2
     clrx  %g1
</pre>
   <p>Finally, the &lsquo;<samp><span class="samp">.nword</span></samp>&rsquo; translating directive is supported
as well.  It is documented in the section on Sparc machine
directives.

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