are predefined and refer to registers.
The exact set depends on the architecture.
</p>

<p>
There are four predeclared symbols that refer to pseudo-registers.
These are not real registers, but rather virtual registers maintained by
the toolchain, such as a frame pointer.
The set of pseudo-registers is the same for all architectures:
</p>

<ul>

<li>
<code>FP</code>: Frame pointer: arguments and locals.
</li>

<li>

and looks for type arguments for those type parameters such that the LHS
and RHS match (become identical or assignment-compatible, depending on
context).
To that effect, type inference maintains a map of bound type parameters
to inferred type arguments; this map is consulted and updated during type unification.
Initially, the bound type parameters are known but the map is empty.