Defining CPU Models (as of M5 2.0 - beta 3)

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First, make sure you have basic understanding of how the CPU models function within the M5 framework. A good start is the CPU Models page.

The easiest way is to derive a new C++ class of your CPU Model from M5 CPU Models that are already defined and the easiest model to start with is probably the 'AtomicSimpleCPU' located in the 'm5/cpu/simple' directory.

After you create a separate directory for your code (e.g. 'm5/cpu/my_cpu'), there are a couple files that need to be updated:

  • m5/SConstruct: Add the name of your CPU model to the 'ALL_CPU_LIST'
  • m5/cpu/SConscript: Add your CPU model and the relevant files that need to be built in here
  • m5/cpu/static_inst.hh: Put a forward class declaration of your model in here
  • m5/cpu/ Add in CPU Model-specific information for the ISA Parser ( check out the ISA Description Language documentation page for more details)
  • m5/python/objects/ Create a python file (e.g. your model. A good example to follow is the file ''.
  • m5/python/objects/ Add the base name of your python file into the 'file_bases' list.

Now build your model:

scons build/ALPHA_SE/m5.debug CPU_MODELS=MY_CPU

If you have dual-core CPU use this to speed-up the compilation:

scons -j3 build/ALPHA_SE/m5.debug CPU_MODELS=MY_CPU

Create and edit configuration files for your model:

  • m5/configs/test/ Define a configuration class w/corresponding parameters for your model. Look to '' in the same directory for an example of how to do this.
  • m5/configs/test/ Import your model's configuration at the top of the file (i.e. 'import MyCPUConfig') and add in a parser option for your CPU model (e.g. '--my_cpu').

Test your model:

build/ALPHA_SE/m5.debug configs/example/ --my_cpu --cmd=<bin_path>