char *
swapstring(str)
	    SV *str
      INIT:
	    STRLEN len;
	    char* buf = SvPVbyte(str, len);
	CODE:

	    while(len--){
		asm("ror $4,%1" : "+r" (buf[len]));
	    }
	    RETVAL = buf;
	OUTPUT:
	    RETVAL