From SimpleScalar website
The SimpleScalar tool set is a system software infrastructure used to build modeling applications for program performance analysis, detailed microarchitectural modeling, and hardware-software co-verification. Using the SimpleScalar tools, users can build modeling applications that simulate real programs running on a range of modern processors and systems. The tool set includes sample simulators ranging from a fast functional simulator to a detailed, dynamically scheduled processor model that supports non-blocking caches, speculative execution, and state-of-the-art branch prediction. The SimpleScalar tools are used widely for research and instruction, for example, in 2000 more than one third of all papers published in top computer architecture conferences used the SimpleScalar tools to evaluate their designs. In addition to simulators, the SimpleScalar tool set includes performance visualization tools, statistical analysis resources, and debug and verification infrastructure.
SimpleScalar LLC is unique in the EDA community. We distribute our software under an open source model, trusting that our users will license the software that they use. The tool set is distributed with all source code, making it possible for users extend SimpleScalar, and to adapt existing models to their own ideas.