minimal-osx-tcc-hello.c

// should work with tcc 0.9.27 from: https://bellard.org/tcc/ which I
// think merges minimal Darwin support from https://github.com/andreiw/tinycc
// (I think only `-run` works; it can't output a Mach-O executable?)
//
// but the header and libc situation on macOS for non-GCC/clang is
// such an incredible mess -- I did kinda get it working, but it's
// more fun to just write something that calls directly into the OS &
// has no dependencies (:
//
//   $ tcc -nostdlib -nostdinc -run minimal-osx-tcc-hello.c
//   Hello.

int main() {
    char str[] = "Hello.\n";

    asm("mov $0x2000004, %%rax;" // write syscall
        "mov $1, %%rdi;" // stdout fd
        "mov %0, %%rsi;" // str
        "mov %1, %%rdx;" // str length (w/o null terminator)
        "syscall"
        :
        : "r" (str), "g" (sizeof str - 1)
        : "rax", "rdi", "rsi", "rdx");

    return 0;
}