sysdeps/alpha/start.S

   1 /* Startup code for Alpha/ELF.
   2    Copyright (C) 1993, 1995, 1996, 1997, 1998, 2000, 2001, 2002, 2003
   3    Free Software Foundation, Inc.
   4    This file is part of the GNU C Library.
   5    Contributed by Richard Henderson <rth@tamu.edu>
   6
   7    The GNU C Library is free software; you can redistribute it and/or
   8    modify it under the terms of the GNU Lesser General Public
   9    License as published by the Free Software Foundation; either
  10    version 2.1 of the License, or (at your option) any later version.
  11
  12    In addition to the permissions in the GNU Lesser General Public
  13    License, the Free Software Foundation gives you unlimited
  14    permission to link the compiled version of this file with other
  15    programs, and to distribute those programs without any restriction
  16    coming from the use of this file. (The GNU Lesser General Public
  17    License restrictions do apply in other respects; for example, they
  18    cover modification of the file, and distribution when not linked
  19    into another program.)
  20
  21    Note that people who make modified versions of this file are not
  22    obligated to grant this special exception for their modified
  23    versions; it is their choice whether to do so. The GNU Lesser
  24    General Public License gives permission to release a modified
  25    version without this exception; this exception also makes it
  26    possible to release a modified version which carries forward this
  27    exception.
  28
  29    The GNU C Library is distributed in the hope that it will be useful,
  30    but WITHOUT ANY WARRANTY; without even the implied warranty of
  31    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  32    Lesser General Public License for more details.
  33
  34    You should have received a copy of the GNU Lesser General Public
  35    License along with the GNU C Library.  If not, see
  36    <http://www.gnu.org/licenses/>.  */
  37
  38 #include <sysdep.h>
  39
  40         .text
  41         .align 3
  42         .globl _start
  43         .ent _start, 0
  44         .type _start,@function
  45 _start:
  46         .frame  $15, 0, $15
  47         br      gp, 1f
  48 1:      ldgp    gp, 0(gp)
  49         subq    sp, 16, sp
  50         mov     0, $15
  51         .prologue 0
  52
  53   /* Load address of the user's main function.  */
  54         lda     a0, main
  55
  56         ldl     a1, 16(sp)      /* get argc */
  57         lda     a2, 24(sp)      /* get argv */
  58
  59   /* Load address of our own entry points to .fini and .init.  */
  60         lda     a3, __libc_csu_init
  61         lda     a4, __libc_csu_fini
  62
  63   /* Store address of the shared library termination function.  */
  64         mov     v0, a5
  65
  66   /* Provide the highest stack address to the user code.  */
  67         stq     sp, 0(sp)
  68
  69   /* Call the user's main function, and exit with its value.
  70      But let the libc call main.  */
  71         jsr     ra, __libc_start_main
  72
  73   /* Die very horribly if exit returns.  Call_pal hlt is callable from
  74      kernel mode only; this will result in an illegal instruction trap.  */
  75         call_pal 0
  76         .end _start
  77
  78 /* For ECOFF backwards compatibility. */
  79 weak_alias (_start, __start)
  80
  81 /* Define a symbol for the first piece of initialized data.  */
  82         .data
  83         .globl __data_start
  84 __data_start:
  85         .weak data_start
  86         data_start = __data_start