     $D0B0/53424/SCPU+64:   SuperCPU Mode Detect Register

       +----------+---------------------------------------------------+
       | Bits 7+6 |   00 = SuperCPU V2 in 128 mode                    |                                    |
       |          |   01 = SuperCPU V2 in 64 mode                     |
       |          |   11 = SuperCPU V1, no or disabled SuperCPU       |
       +----------+---------------------------------------------------+

         This register is read only with hardware registers enabled or
         disabled (write with hardware registers enabled has no effect).