LAPACK/ScaLAPACK Development

I need to compute the eigen-decomposition of a diagonal plus rank one matrix. I know this is done as a part of the divide and conquer algorithm for symmetric tridiagonal matrices (xstedc). Is there an interface for doing only this operation and not the whole tridiagonal eigen-decomposition? Any suggestions? I think I might be able to use xlaed[1-3] in some way.

Thanks
James