write_xaiger - write design to XAIGER file

    write_xaiger [options] [filename]

Write the top module (according to the (* top *) attribute or if only one module
is currently selected) to an XAIGER file. Any non $_NOT_, $_AND_, (optionally
$_DFF_N_, $_DFF_P_), or non (* abc9_box *) cells will be converted into psuedo-
inputs and pseudo-outputs. Whitebox contents will be taken from the equivalent
module in the '$abc9_holes' design, if it exists.

    -ascii
        write ASCII version of AIGER format

    -map <filename>
        write an extra file with port and box symbols

    -dff
        write $_DFF_[NP]_ cells