  Let $A$ be a $n\times n$ real matrix. The piecewise linear equation system
$z-A\vert z\vert =b$ is called an absolute value equation (AVE). It is
well-known to be equivalent to the linear complementarity problem. Unique
solvability of the AVE is known to be characterized in terms of a generalized
Perron root called the sign-real spectral radius of $A$. For mere, possibly
non-unique, solvability no such characterization exists. We narrow this gap in
the theory. That is, we define the concept of the aligned spectrum of $A$ and
prove, under some mild genericity assumptions on $A$, that the mapping degree
of the piecewise linear function $F_A:\mathbb{R}^n\to\mathbb{R}^n\,, z\mapsto
z-A\lvert z\rvert$ is congruent to $(k+1)\mod 2$, where $k$ is the number of
aligned values of $A$ which are larger than $1$. We also derive an exact--but
more technical--formula for the degree of $F_A$ in terms of the aligned
spectrum. Finally, we derive the analogous quantities and results for the LCP.
