addrmap external_registers {

    reg {
        field {} f1 [15:0];
        field {} f2 [31:16];
        f2->sw = w;
    } reg_int0;
    
    // The registers below shall not be implemented by RTL that is
    // generated by srdl2sv but rather, the tool shall provide an
    // interface to communicate with the bus.
    external reg {
        field {} f1 [15:0];
        field {} f2 [31:16];
        f2->sw = w;
    } reg_ext0;
    
    // Multi-dimensional registers must work
    external reg {
        field {} f1 [15:0];
        field {} f2 [31:20];
        f2->sw = w;
    } reg_ext1 [2];

    external reg {
        field {} f1 [14:3];
        field {} f2 [31:20];
        f1->sw = rw;
        f2->sw = rw;
    } reg_ext2 [2];

    // Add an alias to verify that alias capabilities work fine for
    // external registers
    reg reg_ext2_alias_t {
        field {} f1 [14:3];
        f1->sw = rw;
    };

    external alias reg_ext2 reg_ext2_alias_t reg_ext2_alias;

    reg {
        field {} f1 [15:0];
        field {} f2 [31:16];
        f2->sw = w;
    } reg_int1 [2];
};