Below User RPL is System RPL (SysRPL). Most System RPL commands lack argument checking and are defined only for specific argument types (e.g. short integer vs. long integer), making System RPL programs run dramatically faster than equivalent User RPL ones. In addition, System RPL includes many advanced functions that are not available in User RPL. System RPL programs can be created without the use of PC software (although it is available), thanks to the calculator's built-in compiler, MASD. MASD also can compile Saturn assembly language and, with the latest firmware revision for the 49g+/50g, ARMv4T assembly language on the calculator itself. Many tools exist to assist programmers and make the calculator a powerful programming environment.