The CRC code is taken from the Mälardalen WCET benchmark
suite, but altered to
remove undefined behaviour, use int instead of short (which is not fully
supported) and move static arrays out to global variables.
The C parsing and graph export code in CRC.thy is based on the examples in
the graph-refine repository and the SEL4 code. The target.py driver is
based on the graph-refine ones, but has a little extra code added to ignore
the cycle counter variable in loops.