SEGA SATURN DEVELOPER'S MANUAL

x=2-0: Indicates that there are 3,1,03 types. For example, there is DxR26-0 [x = 2-0] in the reading address of Section 3.2 “DMA Control Register”, which means that D2R26-0, D1R26-0, D0R26-0 exist. It is. Similarly, D2R26-0 means that there are D2R26 to D2R0.