/*
 * This header implements the macro 'argcargv(int argc, char **argv)' that
 * sets its two arguments to the argument count and the argument vector,
 * respectively, regardless of:
 *
 *   1) the main function having been declared with or without (argc, argv).
 *   2) the location 'argcargv' is being called from.
 *
 * Thus, in a situation where main is declared as 'main() { ... }' and
 * we are in a function 'foo()' called from 'bar()' called from 'baz()'
 * ... called from 'main()', argcargv() will retrieve argc and argv.
 *
 * Caveat: valid only for the x86 architecture and needs GNU C.
 */

#ifndef _ARGCARGV_H
#define _ARGCARGV_H 1

#if (!(defined(__i386__) && defined(__GNUC__)))
#error "valid only for GNU C on the x86 architecture"
#endif

#define aa_EBP(r) __asm __volatile( \
                "movl %%ebp, %0;" \
                : "=g" (r) : \
        );

#define aa_XREG(r, a) __asm __volatile( \
                "movl (%1), %0;" \
                : "=g" (a) : "g" (r) \
        );

#define aa_AA(argc, argv, base) __asm __volatile( \
                "movl 8(%2), %0;" \
                "movl 12(%2), %1;" \
                : "=g" (argc), "=g" (argv) : "g" (base) \
        );

inline int
__find_main_frame()
{
  int base = 0, _base = 0, __base = 0;

  aa_EBP(__base);
  base = __base;

DOXREG:
  aa_XREG(__base, _base);

  if (_base == 0x0)
    return base;
  else {
    base = __base;
    __base = _base;
    goto DOXREG;
  }
}

#define argcargv(argc, argv) aa_AA(argc, argv, __find_main_frame())

#endif /* _ARGCARGV_H */