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<h3 class="section">4.7 <code>ld</code> and MMIX</h3>

<p>For MMIX, there is a choice of generating <code>ELF</code> object files or
<code>mmo</code> object files when linking.  The simulator <code>mmix</code>
understands the <code>mmo</code> format.  The binutils <code>objcopy</code> utility
can translate between the two formats.

   <p>There is one special section, the &lsquo;<samp><span class="samp">.MMIX.reg_contents</span></samp>&rsquo; section. 
Contents in this section is assumed to correspond to that of global
registers, and symbols referring to it are translated to special symbols,
equal to registers.  In a final link, the start address of the
&lsquo;<samp><span class="samp">.MMIX.reg_contents</span></samp>&rsquo; section corresponds to the first allocated
global register multiplied by 8.  Register <code>$255</code> is not included in
this section; it is always set to the program entry, which is at the
symbol <code>Main</code> for <code>mmo</code> files.

   <p>Global symbols with the prefix <code>__.MMIX.start.</code>, for example
<code>__.MMIX.start..text</code> and <code>__.MMIX.start..data</code> are special. 
The default linker script uses these to set the default start address
of a section.

   <p>Initial and trailing multiples of zero-valued 32-bit words in a section,
are left out from an mmo file.

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