\documentclass{article}

\usepackage[letterpaper, landscape, margin=1cm]{geometry}

\usepackage{tabularx}
\usepackage{tabulary}
\usepackage{booktabs}
\usepackage{tikz}

\usetikzlibrary{shapes.multipart,positioning}

\tikzstyle{stack}=[rectangle split, rectangle split parts=#1,draw,anchor=center]

\newenvironment{opsummary}[2]{%
\begin{tikzpicture}
\newcommand{\opsummaryshort}{#1}
\newcommand{\opsummarylong}{#2}
}{%
\draw[->, double distance=1pt] (before) -- node[above] {\texttt{\opsummaryshort}} node[below] {\texttt{\opsummarylong}} (after);
\end{tikzpicture}
}

\begin{document}

\begin{tabulary}{\textwidth}{@{}cccccccccccccccc@{}} \toprule
    \begin{opsummary}{0}{BNEZ}
        \node[stack=2] (before) {%
            \nodepart{one}$x$
            \nodepart{two}\ldots
        };
        \node[stack=1,right=of before] (after) {%
            \nodepart{one}\ldots
        };
    \end{opsummary}
    &

    \begin{opsummary}{1}{LDAB}
        \node[stack=2] (before) {%
            \nodepart{one}$p$
            \nodepart{two}…
        };
        \node[stack=2,right=of before] (after) {%
            \nodepart{one}$x$
            \nodepart{two}…
        };
    \end{opsummary}
    &

    \begin{opsummary}{2}{LDAS}
        \node[stack=2] (before) {%
            \nodepart{one}$p$
            \nodepart{two}…
        };
        \node[stack=2,right=of before] (after) {%
            \nodepart{one}$x$
            \nodepart{two}…
        };
    \end{opsummary}
    &

    \begin{opsummary}{3}{LDAI}
        \node[stack=2] (before) {%
            \nodepart{one}$p$
            \nodepart{two}…
        };
        \node[stack=2,right=of before] (after) {%
            \nodepart{one}$x$
            \nodepart{two}…
        };
    \end{opsummary}
    &

    \begin{opsummary}{4}{LDAW}
        \node[stack=2] (before) {%
            \nodepart{one}$p$
            \nodepart{two}…
        };
        \node[stack=2,right=of before] (after) {%
            \nodepart{one}$x$
            \nodepart{two}…
        };
    \end{opsummary}
    &

    5 &
    6 &
    7 &
    8 &
    9 &
    A &
    B &
    C &
    D &
    E &
    F \\

    G &
    H &
    I &
    J &
    K &
    L &
    M &
    N &
    O &
    P &
    Q &
    R &
    S &
    T &
    U &
    V \\

\end{tabulary}

\end{document}