How to make self-refering arrow with xydigram in a box

Question

I'm trying to make a nice state diagram with some arrows

I cannot find a way to make the arrows pointing to the same state: in my case, I would like a self-refering arrow to altcache

I'm not fixed about the fancybox, but it would nicely fit in the rest of the thesis.

Thanks a lot for your help

Here is an example of code and the result:

I just need a circle dashed arrow at altcache...

---

\documentclass{article}
\usepackage{amstext}
\usepackage{fancybox}
\usepackage[all]{xy}

\newcommand{\boxsize}{1.4in}
\newcommand{\state}[1]%
  {\doublebox{\text{\begin{minipage}{\boxsize}\centering #1\end{minipage}}}}
\newcommand{\switch}[1]%
  {\ovalbox{\text{\begin{minipage}{\boxsize}\centering #1\end{minipage}}}}

\begin{document}

\xymatrix{
\switch{lscache} \ar@{.>}[d] \ar@{.>}[rdd] &  &\\
\switch{tccache} \ar@{.>}[rd] & & \\
\switch{altcache} & \ar@{.>}[l] \switch{cache}  & \\
}

\end{document}

Answer 1

---

You can specify the exit/entrance directions by adding @(out,in) to the arrow command, where in and out are two direction specifiers (ul, dl, ur, dr, etc.). In order to create a circular arrow above the box altcache, add @(ul,ur):

\xymatrix{
  \switch{lscache}  \ar@{.>}[d] \ar@{.>}[rdd] & &\\
  \switch{tccache}  \ar@{.>}[rd]     & & \\
  \switch{altcache} \ar@{.>}@(ul,ur) & \ar@{.>}[l] \switch{cache}  & 
}