sysdeps/unix/arm/start.c

   1 /* Special startup code for ARM a.out binaries.
   2    Copyright (C) 1998 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Library General Public License as
   7    published by the Free Software Foundation; either version 2 of the
   8    License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Library General Public License for more details.
  14
  15    You should have received a copy of the GNU Library General Public
  16    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  17    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  18    Boston, MA 02111-1307, USA.  */
  19
  20 #include <errno.h>
  21 #include <stdlib.h>
  22 #include <unistd.h>
  23 #include <sysdep.h>
  24
  25 /* The first piece of initialized data.  */
  26 int __data_start = 0;
  27 #ifdef HAVE_WEAK_SYMBOLS
  28 weak_alias (__data_start, data_start)
  29 #endif
  30
  31 #ifndef errno
  32 volatile int __errno;
  33 strong_alias (__errno, errno)
  34 #endif
  35
  36 extern void __libc_init __P ((int argc, char **argv, char **envp));
  37 extern int main __P ((int argc, char **argv, char **envp));
  38
  39 /* N.B.: It is important that this be the first function.
  40    This file is the first thing in the text section.  */
  41
  42 /* If this was in C it might create its own stack frame and
  43    screw up the arguments.  */
  44 #ifdef NO_UNDERSCORES
  45 asm (".text; .globl _start; _start: B start1");
  46 #else
  47 asm (".text; .globl __start; __start: B _start1");
  48
  49 /* Make an alias called `start' (no leading underscore, so it can't
  50    conflict with C symbols) for `_start'.  This is the name vendor crt0.o's
  51    tend to use, and thus the name most linkers expect.  */
  52 asm (".set start, __start");
  53 #endif
  54
  55 /* Fool gcc into thinking that more args are passed.  This makes it look
  56    on the stack (correctly) for the real arguments.  It causes somewhat
  57    strange register usage in start1(), but we aren't too bothered about
  58    that at the moment. */
  59 #define DUMMIES a1, a2, a3, a4
  60
  61 #ifdef  DUMMIES
  62 #define ARG_DUMMIES     DUMMIES,
  63 #define DECL_DUMMIES    int DUMMIES;
  64 #else
  65 #define ARG_DUMMIES
  66 #define DECL_DUMMIES
  67 #endif
  68
  69 /* ARGSUSED */
  70 static void
  71 start1 (ARG_DUMMIES argc, argv, envp)
  72      DECL_DUMMIES
  73      int argc;
  74      char **argv;
  75      char **envp;
  76 {
  77   /* Store a pointer to the environment.  */
  78   __environ = envp;
  79
  80   /* Do C library initializations.  */
  81   __libc_init (argc, argv, __environ);
  82
  83   /* Call the user program.  */
  84   exit (main (argc, argv, __environ));
  85 }