</p>

<p>
On architectures with a hardware register named <code>SP</code>,
the name prefix distinguishes
references to the virtual stack pointer from references to the architectural
<code>SP</code> register.
That is, <code>x-8(SP)</code> and <code>-8(SP)</code>
are different memory locations:
the first refers to the virtual stack pointer pseudo-register,
while the second refers to the