addrmap Peripheral {
    regfile {
        default regwidth = 32;

        reg {
            name = "Fields";
            field {
                name = "FIRST";
                sw = r;
                hw = w;
            } first [7:0];
            field {
                name = "SECOND";
                sw = w;
                hw = r;
            } second [15:8];
            field {
                name = "THIRD";
                sw = rw;
                hw = rw;
                onwrite = woclr;
            } third [23:16];
            field {
                name = "FOURTH";
                sw = rw;
                hw = rw;
                onread = rclr;
            } fourth [31:24];
        } fields @ 0x0;
    } registers @ 0x0;
};