sysdeps/ia64/elf/start.S

   1 /* Copyright (C) 1999, 2000, 2001, 2002 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Written by Jes Sorensen, <Jes.Sorensen@cern.ch>, April 1999.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    In addition to the permissions in the GNU Lesser General Public
  11    License, the Free Software Foundation gives you unlimited
  12    permission to link the compiled version of this file with other
  13    programs, and to distribute those programs without any restriction
  14    coming from the use of this file. (The GNU Lesser General Public
  15    License restrictions do apply in other respects; for example, they
  16    cover modification of the file, and distribution when not linked
  17    into another program.)
  18
  19    Note that people who make modified versions of this file are not
  20    obligated to grant this special exception for their modified
  21    versions; it is their choice whether to do so. The GNU Lesser
  22    General Public License gives permission to release a modified
  23    version without this exception; this exception also makes it
  24    possible to release a modified version which carries forward this
  25    exception.
  26
  27    The GNU C Library is distributed in the hope that it will be useful,
  28    but WITHOUT ANY WARRANTY; without even the implied warranty of
  29    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  30    Lesser General Public License for more details.
  31
  32    You should have received a copy of the GNU Lesser General Public
  33    License along with the GNU C Library; if not, write to the Free
  34    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  35    02111-1307 USA.  */
  36
  37 #include <sysdep.h>
  38
  39 #include <asm/unistd.h>
  40 #include <asm/fpu.h>
  41
  42 /*
  43  * Arguments for __libc_start_main:
  44  *      out0:   main
  45  *      out1:   argc
  46  *      out2:   argv
  47  *      out3:   init
  48  *      out4:   fini
  49  *      out5:   rtld_fini
  50  *      out6:   stack_end
  51  */
  52
  53         .align 32
  54         .global _start
  55
  56         .proc _start
  57         .type _start,@function
  58 _start:
  59         .prologue
  60         .save rp, r0
  61         .body
  62         .prologue
  63         { .mlx
  64           alloc r2 = ar.pfs,0,0,7,0
  65           movl r3 = FPSR_DEFAULT
  66         }
  67         { .mlx
  68           adds out2 = 16, sp    /* get address of argc value */
  69           movl gp = @gprel(0f)
  70           ;;
  71         }
  72 0:      { .mmi
  73           ld8 out1 = [out2], 8  /* load argc and move out2 to become argv */
  74           mov.m r10 = ar.bsp    /* fetch rbs base address */
  75           mov r9 = ip
  76           ;;
  77         }
  78         { .mii
  79           mov ar.fpsr = r3
  80           sub gp = r9, gp       /* back-compute gp value */
  81           adds out6 = 16, sp    /* highest non-environment stack address */
  82           ;;
  83         }
  84         {
  85           addl r11 = @ltoff(__libc_ia64_register_backing_store_base), gp
  86           addl out0 = @ltoff(@fptr(main)), gp
  87           addl out3 = @ltoff(@fptr(__libc_csu_init)), gp
  88           ;;
  89         }
  90         { .mmi
  91           ld8 r3 = [r11]        /* pointer to __libc_ia64_register_backing_store_base */
  92           ld8 out0 = [out0]     /* pointer to `main' function descriptor */
  93           addl out4 = @ltoff(@fptr(__libc_csu_fini)), gp
  94           ;;
  95         }
  96         { .mmi
  97           ld8 out3 = [out3]     /* pointer to `init' function descriptor */
  98           ld8 out4 = [out4]     /* pointer to `fini' function descriptor */
  99           nop 0
 100         }
 101         .body
 102         { .mib
 103           st8 [r3] = r10
 104           mov out5 = ret0       /* dynamic linker destructor */
 105           br.call.sptk.few rp = __libc_start_main
 106         }
 107         { .mib
 108           break 0       /* break miserably if we ever return */
 109         }
 110         .endp _start
 111
 112 /* Define a symbol for the first piece of initialized data.  */
 113         .data
 114         .globl __data_start
 115 __data_start:
 116         .long 0
 117         .weak data_start
 118         data_start = __data_start
 119
 120         .common __libc_ia64_register_backing_store_base, 8, 8