ex5_exponent.dot

// Data-flow diagram for Exponent register machine

digraph Exponent {
        // the stack
        stack [shape=box];
        
        // labels
        "expt-done" [shape=triangle];
        "after-expt" [shape=triangle];

        // constants
        1 [shape=triangle];
        0 [shape=triangle];

        // registers
        n [shape=box];
        b [shape=box];
        continue [shape=box];
        val [shape=box];
        
        // operations
        "*" [shape=polygon,sides=4,distortion=0.6];
        "-" [shape=polygon,sides=4,distortion=0.6];

        // tests
        "=";

        // edges
        "expt-done" -> continue;
        n -> "=";
        0 -> "=";
        continue -> stack;
        "after-expt" -> continue;
        "-" -> n;
        n -> "-";
        1 -> "-";
        stack -> continue;
        "*" -> val;
        val -> "*";
        b -> "*";
        1 -> val;
}