The Hitachi H8/300 target family toolchain controls variances in code generation directly from the command line.
When you run GCC, you can use command-line options to
choose whether to take advantage of the extra Hitachi H8/300 machine
instructions, and whether to generate code for hardware or software floating
point.
This special release includes support for the C++ language. This support may in certain circumstances add up to 5K to the size of your executables.
The new C++ support involves new startup code that runs C++ initializers before `main()' is invoked. If you have a replacement for the file `crt0.o' (or if you call `main()' yourself) you must call `_main()' before calling `main()'.
You may need to run these C++ initializers even if you do not write in C++ yourself. This could happen, for instance, if you are linking against a third-party library which itself was written in C++. You may not be able to tell that it was written in C++ because you are calling it with C entry points prototyped in a C header file. Without these initializers, functions written in C++ may malfunction.
If you are not using any third-party libraries, or are otherwise certain that you will not require any C++ constructors you may suppress them by adding the following definition to your program:
int __main() {}