#define __NR_exit 60
#define __NR_write 1

typedef long ssize_t;
typedef unsigned long size_t;

int  errno = 0;

static unsigned long
errno_munge(unsigned long r)
{
    if ((long)r < 0 && (long)r > -4096) {
        errno = -r;
        return (unsigned long)-1;
    } else {
        return r;
    }
}

unsigned long
_syscall1(int sysnr, unsigned long arg)
{
    unsigned long res;
    asm ("syscall\n"
         : "=a" (res)
         : "0" (sysnr), "D" (arg)
         : "memory");
    return errno_munge(res);
}

unsigned long
_syscall3(int sysnr, unsigned long arg1, unsigned long arg2, unsigned long arg3)
{
    unsigned long res;
    asm ("syscall\n"
         : "=a" (res)
         : "0" (sysnr), "D" (arg1), "S" (arg2), "d" (arg3)
         : "memory");
    return errno_munge(res);
}

void
exit(int code)
{
    _syscall1(__NR_exit, code);
}

ssize_t
write(int fd, const void *buf, size_t sz)
{
    return _syscall3(__NR_write, fd, (unsigned long)buf, sz);
}

int
main(int argc, char *argv[])
{
    write(1, "HELLO WORLD\n", sizeof("HELLO WORLD\n"));
    return argc;
}

void _start()
    __asm__("pop %rdi");
    __asm__("movq %rsp, %rsi");
    __asm__("lea -8(%rsp),%rsp");
    __asm__("call main");
    __asm__("mov %rax, %rdi");
    __asm__("call exit");