Change log:
1. code_generator , format is roughly completed.
2. The program has not been tested.

Unsolved compile error:

    code_generator.o:(.data+0x0): multiple definition of `fields'
    assembler.o:(.data+0x0): first defined here
    code_generator.o:(.data+0x40): multiple definition of `format'
    assembler.o:(.data+0x40): first defined here

`fields` and `format` are global variables.  They're first defined
in bitsOperation.c , and declared in bitsOperation.h ( extern
declaration ).  I think it should have worked.