RetroArch/android/andretro/assets/libretro_prboom.so.xml

<retro>
    <system fullname="DOOM" shortname="doom"/>
    <module libraryname="prboom" extensions="wad|iwad"/>
    
    <input>
        <port shortname="p1" fullname="Player 1" defaultdevice="pad">
            <device shortname="pad" fullname="Gamepad">
                <button shortname="up" fullname="Up" mappedkey="UP"/>
                <button shortname="down" fullname="Down" mappedkey="DOWN"/>
                <button shortname="left" fullname="Left" mappedkey="LEFT"/>
                <button shortname="right" fullname="Right" mappedkey="RIGHT"/>
                <button shortname="strafeleft" fullname="Strafe Left" mappedkey="L1"/>
                <button shortname="straferight" fullname="Strafe Right" mappedkey="R1"/>

                <button shortname="fire" fullname="Fire" mappedkey="X"/>
                <button shortname="use" fullname="Use" mappedkey="A"/>
                <button shortname="run" fullname="Run" mappedkey="Y"/>                
                <button shortname="strafe" fullname="Strafe" mappedkey="B"/>                

                <button shortname="menu" fullname="Menu" mappedkey="START"/>
                <button shortname="map" fullname="Map" mappedkey="SELECT"/>

                <button shortname="prevweapon" fullname="Previous Weapon" mappedkey="L2"/>
                <button shortname="nextweapon" fullname="Next Weapon" mappedkey="R2"/>
            </device>
        </port>
    </input>
    
</retro>