MIPS32 Simulator -- "1/25th the performance at none of the cost"

Spim/Xspim simulates MIPS32 assembly code, providing a gdb and xgdb
like interface to the classical MIPS RISC CPU.  The virtual machine
it provides can be either the one presented by the MIPS assembler or the
one of the bare hardware.  The simulator can also be built to simulate the
pipeline architecture of the MIPS machine (both the control and floating
point pipelines).  When built for this, it also simulates and displays
an instruction and data cache.

This simulator is useful in CS and EE classes, including providing a
target machine for compilers courses, lower division assembly language
programming, microprocessor design courses, etc...