constant SI_BASE($A480)         // $04800000..$0480001B Serial Interface (SI) Base Register
constant SI_DRAM_ADDR($00)      // $04800000..$04800003 SI: DRAM Address Register
constant SI_PIF_ADDR_RD64B($04) // $04800004..$04800007 SI: Address Read 64B Register
//*RESERVED*($08)               // $04800008..$0480000B SI: Reserved Register
//*RESERVED*($0C)               // $0480000C..$0480000F SI: Reserved Register
constant SI_PIF_ADDR_WR64B($10) // $04800010..$04800013 SI: Address Write 64B Register
//*RESERVED*($14)               // $04800014..$04800017 SI: Reserved Register
constant SI_STATUS($18)         // $04800018..$0480001B SI: Status Register