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<a name="Emulation-Primitives"></a>
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<a name="Emulation-Primitives-1"></a>
<h2 class="section">3.8 Emulation Primitives</h2>

<p>The functions documented in this section can be used to take very
specific control over the evaluation of virtual code applications. It is
unlikely that a client program will have any need for them unless it
aims to replace or extend the <code>avm_apply</code> function.
</p>
<p>The virtual machine is somewhat removed from a conventional von Neumann
model of computation, so emulating it in C or any other imperative
language is less straightforward than one would prefer. An elaborate
system of interdependent data structures is used to represent partially
evaluated computations, which does not particularly lend itself to a
convenient, modular API. The abstraction provided by the functions in
this section is limited mainly to that of simple memory management and
stack operations. Consequently, a developer wishing to build on them
effectively would need to <em>grok</em> the data structures involved,
which are described in some detail.
</p>
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<tr><td align="left" valign="top"><a href="Lists-of-Pairs-of-Ports.html#Lists-of-Pairs-of-Ports">3.8.1 Lists of Pairs of Ports</a></td><td>&nbsp;&nbsp;</td><td align="left" valign="top">     
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<tr><td align="left" valign="top"><a href="Ports-and-Packets.html#Ports-and-Packets">3.8.2 Ports and Packets</a></td><td>&nbsp;&nbsp;</td><td align="left" valign="top">           
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<tr><td align="left" valign="top"><a href="Instruction-Stacks.html#Instruction-Stacks">3.8.3 Instruction Stacks</a></td><td>&nbsp;&nbsp;</td><td align="left" valign="top">          
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