sysdeps/alpha/start.S

   1 /* Startup code for Alpha/ELF.
   2    Copyright (C) 1993-2019 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4    Contributed by Richard Henderson <rth@tamu.edu>
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Lesser General Public
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the License, or (at your option) any later version.
  10
  11    In addition to the permissions in the GNU Lesser General Public
  12    License, the Free Software Foundation gives you unlimited
  13    permission to link the compiled version of this file with other
  14    programs, and to distribute those programs without any restriction
  15    coming from the use of this file. (The GNU Lesser General Public
  16    License restrictions do apply in other respects; for example, they
  17    cover modification of the file, and distribution when not linked
  18    into another program.)
  19
  20    Note that people who make modified versions of this file are not
  21    obligated to grant this special exception for their modified
  22    versions; it is their choice whether to do so. The GNU Lesser
  23    General Public License gives permission to release a modified
  24    version without this exception; this exception also makes it
  25    possible to release a modified version which carries forward this
  26    exception.
  27
  28    The GNU C Library is distributed in the hope that it will be useful,
  29    but WITHOUT ANY WARRANTY; without even the implied warranty of
  30    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  31    Lesser General Public License for more details.
  32
  33    You should have received a copy of the GNU Lesser General Public
  34    License along with the GNU C Library.  If not, see
  35    <http://www.gnu.org/licenses/>.  */
  36
  37 #include <sysdep.h>
  38
  39         .text
  40         .align 3
  41         .globl _start
  42         .ent _start, 0
  43         .type _start,@function
  44 _start:
  45         .frame  $15, 0, $15
  46         br      gp, 1f
  47 1:      ldgp    gp, 0(gp)
  48         subq    sp, 16, sp
  49         mov     0, $15
  50         .prologue 0
  51
  52   /* Load address of the user's main function.  */
  53         lda     a0, main
  54
  55         ldl     a1, 16(sp)      /* get argc */
  56         lda     a2, 24(sp)      /* get argv */
  57
  58   /* Load address of our own entry points to .fini and .init.  */
  59         lda     a3, __libc_csu_init
  60         lda     a4, __libc_csu_fini
  61
  62   /* Store address of the shared library termination function.  */
  63         mov     v0, a5
  64
  65   /* Provide the highest stack address to the user code.  */
  66         stq     sp, 0(sp)
  67
  68   /* Call the user's main function, and exit with its value.
  69      But let the libc call main.  */
  70         jsr     ra, __libc_start_main
  71
  72   /* Die very horribly if exit returns.  Call_pal hlt is callable from
  73      kernel mode only; this will result in an illegal instruction trap.  */
  74         call_pal 0
  75         .end _start
  76
  77 /* For ECOFF backwards compatibility. */
  78 weak_alias (_start, __start)
  79
  80 /* Define a symbol for the first piece of initialized data.  */
  81         .data
  82         .globl __data_start
  83 __data_start:
  84         .weak data_start
  85         data_start = __data_start