Compiling C and assembling ASM into machine code [closed]

Question

I have three questions:

1. What compiler can I use and how can I use it to compile C source code into machine code?
2. What assembler can I use and how can I use it to assemble ASM to machine code?
3. (optional) How would you recommend placing machine code in the proper addresses (i.e. bootloader machine code must be placed in the boot sector)?

My goal: I'm trying to make a basic operating system. This would use a personally made bootloader and kernel. I would also try to take bits and pieces from the Linux kernel (namely the drivers) and integrate them into my kernel. I hope to create a 32-bit DOS-like operating system for messing with memory on most modern computers. I don't think I will be creating a executable format for my operating system, as my operating system wont be dynamic enough to require it.

My situation: I'm running on a x86-64 windows 8 laptop with a Intel Celeron CPU; I believe it uses secure boot. I would be testing my operating system on a x86-64 desktop with Intel Core I3 CPU. I have a average understanding of operating systems and their techniques. I know the C, ASM, and computer theory required for this project. I think it is also note worthy that I'm sixteen with no formal education about computer science.

My research: After searching Google for what C normally compiles into, I found answers ranging from machine code, binary, plain binary, raw binary, assembly, and relocatable object code. Assembly as I understand normally assembles into a PE formatted executable. I have heard of the Cygwin, GCC C, and MingW C compilers. As for assemblers, I have heard of FASM, MASM, and NASM. I have searched websites such as OSDev and OSDever.

What I have tried: I tried to setup GCC (a nightmare) and create a cross compiler (another nightmare).

Conclusion: As you can tell, I'm vary confused about compilers, assemblers, and executable formats. Please dispel my ignorance along with answering my questions. These are probably the only things keeping me from having a OS on my resume. Sorry, I would have included more links, but stackoverflow wouldn't let me make more then two. Thanks a ton!

Answer 1

First, some quick answers to your three questions.

1. Pretty much any compiler will translate C code into assembly code. That's what compilers do. GCC and clang are popular and free.

   clang -S -o example.s example.c
   

2. Whichever compiler you choose will probably support assembly as well, simply by using the same compiler driver.

   clang -o example.o example.s
   

3. Your linker documentation will tell you how to put specific code at specific addresses and so forth. If you use GCC or clang as described above, you will probably use ld(1). In that case, read into 'linker scripts'.

Next, some notes:

• You don't need a cross compiler or to set up GCC by yourself. You're working on an Intel machine, generating code for an Intel machine. Any binary distribution of clang or GCC that comes with your linux distribution should work fine.

• C compilers normally compile code into assembly, and then pass the resulting assembly off to a system assembler to end up with machine code. Machine code, binary, plain binary, raw binary, are all basically synonymous.

• The generated machine code is packaged into some kind of executable file format, to tell the host operating system how to load and run the code. On windows, it's PE, on Linux, it's ELF, and on Mac OS X it's Mach-O.

• You don't need to create an executable format for your OS, but you will probably want to use one. ELF is a pretty straightforward (and well-documented) option.

And a bit of a personal note that I hope doesn't discourage you too much - If you are not very familiar with how compilers, assemblers, linkers, and all of those tools work, your project is going to be very difficult and confusing. You might want to start with some smaller projects to get your "sea legs", so to speak.