spim is a self-contained software simulator for running R2000/R3000 assembly language programs. It reads and can immediately execute files containing assembly language code. spim also provides a debugger and simple set of operating system services. spim provides both a simple, textual interface and a fancier, graphical interface. The package includes complete source code and documentation.
Opdis is a wrapper for the libopcodes disassembler library distributed as part of GNU binutils. It extends the libopcodes library by offering linear and control-flow disassembly algorithms, instruction and operand objects that are suitable for analysis, and a command-line utility to perform disassembly on arbitrary locations in a file. The Opdis project consists of the libopdis library and the opdis command-line utility. There is a Ruby gem providing access to libopdis, and a supporting gem providing access to libbfd.