The MPC problem setup description is found in firefly.py, which is here without disturbance states.
The automatically generated code are in the cmpc directory.
All the available constants are found in cmpc/include/mpc_const.h.
cmpc/include/mpc_base.h includes the type definition real_t, which is the type for all numeric operations of the algorithm. By default, the generated code uses double precision float (64-bit) for all computations.
firefly_mpc.c is a test file to make use of the generated code.