Is it possible to run a C-File using an ARM CPU emulator?

Question

I had the idea of emulating an ARM CPU to run different programs. To begin with, I wanted emulate the CPU and run for example a simple "hello world" written in C.

Sadly I found no answer using Google etc.

Is it possible to run, for example a C-File using an ARM CPU emulator?

I thought of emulating a CPU without GUI – just using the command-line on which I want to run the C-file.

Answer 1

The answer is no. A CPU only understands CPU instructions, aka assembler language. When you have a C-File, and you want to run it, you need an interpreter to make the CPU understand the script. This means the script is compiled into a binary executable which is a list of assembly instructions that the CPU will understand.

But if your CPU emulator has some kind of interface and operating system, then you can use that operating system to run a compiler and in that case you can run a C-File through the compiler. But the operating system is the GUI you want to avoid, so... that leads me back to the first paragraph.

Answer 2

Your question was whether you can test a given C file on a CPU architecture different from the machine you're working on. For example, you may have a Windows machine with an Intel processor, but want to try the program on an ARM platform. This can of course be done.

The thing to note is that C code never runs directly on a CPU; it first has to be translated (compiled) into machine code, as different platforms require different machine code to do the same thing. This is what a compiler does.

You can tell a compiler to compile your code into a different target platform. This is called cross-compiling. This blog post, for example, describes how to cross-compile a Hello World program to ARM using the arm-linux-gnueabi-gcc compiler (which you can get under Ubuntu from apt install gcc-arm-linux-gnueabi).

I should add that these sort of things are somewhat easier under Linux hosts than Windows, but maybe that's a personal bias.

Once you have cross-compiled your program, you may want to test it on the target platform. For this, you will need a CPU emulator, of course, but that emulator alone will not be enough, as you need an operating system on top of it,^* which can load the respective compiled C program and execute it as a process. The ARM Lab VM does that for ARM. It's a virtual machine that emulates an ARM platform on any host platform.

_{* Unless that program itself is “bare-metal”, which means that it runs without an intermediate operating system.}