about carbone/comp/generator.c:

  This is the file that implements the last step in compilation:
  generation of a sequence of instructions

  All the functions that begin with  `gen_' and end with the name of a
  VM instruction  (defined in vm/rb-inst.vmg) call  functions that are
  automatically generated by vmgen.

  Each of them appends the named instruction to the code pointer given
  as first param and increments the code pointer.

  All other  arguments are immediate values for  the instruction (They
  are saved in the instruction stream. Thats also the reason why those
  functions  have the  responsibility to  increment the  code pointer.
  Each  instruction  can  have  arbitrary  many  immediate  values  as
  parameters;  This information  can be  won from  the  VM description
  (vm/rb-inst.vmg):  All  parameters  that  are prefixed  by  `#'  are
  imm. see vm/gen/rb-gen.i