盒子的矩形“标签”

Question

我在创建其中一个图表时遇到了问题。我找不到一种不那么老套的方法，比如将标签放在此图表中绘制的矩形上方：

\documentclass[border=0.2cm]{standalone}

\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}

\usepackage{tikz}
\usepackage{circuitikz}
\usepackage{siunitx}

\usetikzlibrary{calc}
\usetikzlibrary{positioning}


\tikzset{
    box/.style={teal, ultra thick, dashed},
    item/.style={cyan!.9!blue, draw=cyan!80, minimum width=5cm, minimum height=1cm, text width=3cm,align=center,fill=cyan!10},
    operation block/.style={green!.9!teal,draw=teal!80, minimum width=2cm, minimum height=2cm, text width=2cm,align=center,fill=teal!10},
    variable input/.style={draw=teal!80, minimum width=.5cm, minimum height=.5cm,fill=teal!20},
    accumulator/.style={green!.9!teal, draw=teal!80, minimum width=1cm, minimum height=2cm,fill=teal!10},
    status register/.style={draw=teal!80, minimum width=.5cm, minimum height=1.5cm,fill=teal!20},
    instruction path/.style={-Latex, blue, thick},
    data path/.style={-Latex, red, line width=1mm},
    data path reverse/.style={Latex-, red, line width=1mm},
}

\begin{document}
\begin{circuitikz}[european, straight voltages]

    \draw (0, 0) node[item] (RI) {Registr instrukce} 
        ++(0, -3) node[item] (DI) {Dekodér instrukce}
        ++(0, -1.5) node[item] (GRI) {Generátor\\řídících impulzů};

    \draw ($(RI.north west)!.5!(DI.south west)$) ++(-3.5, 0) node[item] (RA) {Registr adresy};
    
    \foreach \where in {0.25, 0.5, 0.75} {
         \draw [instruction path] ($(DI.south west)!\where!(DI.south east)$) -- ($(GRI.north west)!\where!(GRI.north east)$);
    }

    \draw [instruction path] ($(GRI.north west)!.5!(GRI.south west)$) -- ++(-.5, 0) |- ($(RI.south west)!.5!(RI.north west)$);
    \draw [instruction path] ($(GRI.north west)!.5!(GRI.south west)$) -- ++(-.5, 0) |- ($(RA.south east)!.5!(RA.north east)$);

    \draw [data path] ($(RI.south west)!.5!(RI.south east)$) -- ($(DI.north west)!.5!(DI.north east)$);
    \draw [data path] ($(RA.south west)!.5!(RA.south east)$) -- ++(0, -6.5) coordinate (addr_out);
    \draw (addr_out) ++(0, -0.25) node[] {Výstup adres}; 

    \draw [data path reverse] ($(RI.north west)!.5!(RI.north east)$) -- ++(0, 1) coordinate (data_in) -- ++(0, 2) coordinate (data_in_label);
    \draw (data_in_label) ++(0, .25) node[] {Vstup dat};
    \draw [data path reverse] ($(RA.north west)!.5!(RA.north east)$) -- (data_in-|RA) -- (data_in);

    \draw [box, cyan!80] ($(RA.north west)+(-0.3,2.2)$) rectangle ($(GRI.south east)+(0.3,-0.6)$);
    \draw ($(RA.north west)+(0.3,2.3)$) node[cyan!80, above] {\textbf{Řadič}}; % FIXME: Find better positioning hack

    \draw (GRI) ++(10, -1) node[operation block] (OB) {Operační\\blok};
    \draw (OB.north east) ++(.5, -.1) node[variable input, anchor=north east] (OB_a) {};
    \draw (OB.south east) ++(.5, +.1) node[variable input, anchor=south east] (OB_b) {};

    \draw (OB) ++(-3, 0) node[accumulator] (ACC) {Střádač};

    \draw [data path] ($(OB.north west)!.5!(OB.south west)$) -- ($(ACC.north east)!.5!(ACC.south east)$);
    \draw [data path] ($(ACC.north west)!.75!(ACC.north east)$) -- ++(0, .5) coordinate (j0) -- (j0-|OB_a.east) -- ++(1, 0) |- (OB_a);
    \draw [data path] ($(ACC.south west)!.75!(ACC.south east)$) coordinate (j1) -- (j1|-addr_out) coordinate (data_out);
    \draw (data_out) ++(0, -0.25) node[] {Výstup dat}; 

    \draw (ACC.north west) ++(-.05, 0) node[status register, anchor=north east] (SR) {};

    \draw [box] ($(SR.north west)+(-0.3,1.5)$) rectangle ($(OB_b.south east)+(0.3,-1)$);
    \draw ($(SR.north west)+(4.3,1.5)$) node[teal, above] {\textbf{Aritmetická jednotka}}; % FIXME: Find better positioning hack

    \draw ($(ACC.south west)!.25!(ACC.south east)$) coordinate (acc_instr_in); % Prepare the midpoint for the path label
    \draw [instruction path] (GRI.south) -- ++(0, -2)  coordinate (j6) -- (j6-|acc_instr_in) node[below, midway] {Řídící signály} -- (acc_instr_in);
    
    \draw ($(ACC.north west)!.25!(ACC.north east)$) coordinate (j4);
    \draw [data path] (data_in) -- (data_in-|j4) -- (j4);

    \draw [instruction path] ($(GRI.north east)!.15!(GRI.south east)$) -| ($(OB.north east)!.5!(OB.north west)$);
    \draw [instruction path] ($(GRI.north east)!.75!(GRI.south east)$) coordinate (j2) -- (j2-|SR.west) coordinate (j3);
    \draw (j3) ++(0, -0.25) [instruction path] -- ++(-2, 0) node[teal, midway, below, xshift=-0.55cm] (SR_label) {reg. příznaků};

    \draw (SR_label) ++(0, 2) node[blue, text width=2cm] {Řízení\\ artimetické\\ jednotky};

    \draw [data path] (j4) ++(0, 1) coordinate (j5) -- (j5-|OB_b.east) -- ++(1.25, 0) |- (OB_b);
\end{circuitikz}
\end{document}

期望的结果如图所示，我只是想找到一些巧妙的方法，而不是从框坐标手动计算它：

感谢你的帮助！