Tag Archives: subnotebook

Adventures In MIPS Tools

I’m trying to compile a program that will run on my new MIPS-based subnotebook. I finally got a cross-compiling toolchain built and building a super-simple C program. But the program failed to run. When I tried to run my sample program, the shell complained about not knowing what to do with a ‘(‘ character. Puzzling.

This is the ‘file’ type of my compiled program:

ELF 32-bit MSB executable, MIPS, MIPS-I version 1 (SYSV), statically linked, not stripped

I finally thought to extract a binary from the MIPS machine and check its file type:

ELF 32-bit LSB executable, MIPS, version 1 (SYSV), dynamically linked (uses shared libs), stripped

Okay, I think I’m getting wise to the discrepancy already. It turns out that I want a target called “mipsel” rather than just plain “mips” as the former specifies little endian (and because a MIPS CPU can be wired to run either endian — that’s how simple and reduced this reduced instruction set is).

So I rebuilt the toolchain using the ‘mipsel’ target (building the toolchain is surprisingly quick when you know how). Now the test program segfaults when I try to run it. That’s unfortunate, though I still perceive it to be a step up from the last position. This is the new type reported by ‘file’:

ELF 32-bit LSB executable, MIPS, MIPS-I version 1 (SYSV), statically linked, not stripped

It’s MIPS-I version 1, vs. simply MIPS version 1, which is what the existing binaries are. I wonder if that’s the problem? I’m also struggling with a linker warning about the start location. That’s more likely to be the issue.

BTW, this is the C code I am testing with:

int main()
{
  return 77;
}

My thinking here is that I should be able to run the program followed by “echo $?” to get the last command’s exit status– 77 in this case.