MIPS (Microprocessor without Interlocked Pipeline Stages) is a reduced instruction set computing (RISC) instruction set architecture (ISA) developed by MIPS Technologies. The early MIPS architectures were 32-bit, while later versions were 64-bit. Multiple revisions of the MIPS instruction set exist. The current revisions are MIPS32 (for 32-bit implementations) and MIPS64 (for 64-bit implementations). MIPS32 and MIPS64 define a control register set as well as the instruction set.


Spim is a self-contained simulator that will run MIPS R2000/R3000 (two earliest MIPS versions) assembly language programs. It reads and immediately executes assembly language code for this processor (it does not execute binary programs). Spim provides a simple debugger and minimal set of operating system services:

• MARS: MARS is a lightweight interactive development environment (IDE) for programming in MIPS assembly language.


• QtSpim: The newest version of Spim is called QtSpim, and unlike other versions, it runs on Microsoft Windows, Mac OS X, and Linux.


• Spim: On Unix, the spim program provides the terminal interface and the xspim program provides the X window interface.


• PCSpim: On PCs, PCSpim provides the Windows interface.