ports/sysdeps/hppa/start.S

   1 /* ELF startup code for HPPA.
   2    Copyright (C) 2002-2013 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 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, see
  34    <http://www.gnu.org/licenses/>.  */
  35
  36         .import main, code
  37         .import $global$, data
  38         .import __libc_start_main, code
  39         .import __libc_csu_fini, code
  40         .import __libc_csu_init, code
  41
  42         /* Have the linker create plabel words so we get PLABEL32
  43            relocs and not 21/14.  The use of 21/14 relocs is only
  44            supported in the latest dynamic linker.  */
  45         .section        .rodata
  46         .align 4
  47 .Lpmain:
  48         .word P%main
  49 .Lp__libc_start_main:
  50         .word P%__libc_start_main
  51 .Lp__libc_csu_fini:
  52         .word P%__libc_csu_fini
  53 .Lp__libc_csu_init:
  54         .word P%__libc_csu_init
  55
  56         .text
  57         .align 4
  58         .globl _start
  59         .export _start, ENTRY
  60         .type _start,@function
  61 _start:
  62         /* At entry to the function we have:
  63
  64                 r26 - Unused
  65                 r25 - argc
  66                 r24 - argv
  67                 r23 - False _dl_fini plabel address
  68
  69            This function is called from the lower half of RTLD_START.
  70
  71            The call to __libc_start_main expects:
  72
  73                 1. r26 - Application main
  74                 2. r25 - argc
  75                 3. r24 - argv
  76                 4. r23 - __libc_csu_init
  77                 5. sp-52 - __libc_csu_fini
  78                 6. sp-56 - rtld_fini
  79                 7. sp-60 - stackend  */
  80
  81         .proc
  82         .callinfo
  83         /* Clear previous-sp.  */
  84         stw     %r0, -4(%sp)
  85         /* Setup the stack and frame.  */
  86         stw     %rp, -20(%sp)
  87         ldo     64(%sp), %sp
  88         stw     %sp, -4(%sp)
  89         stw     %r19, -32(%sp)
  90
  91         /* argc and argv should be in 25 and 24 (2nd and 3rd argument) */
  92         /* void (*rtld_fini) (void) (6th argument) */
  93         stw     %r23, -56(%sp)
  94         /* Need to setup 1, 4, 5, and 7th arguments */
  95
  96 #if SHARED
  97         /* load main (1st argument) */
  98         addil   LT'.Lpmain, %r19
  99         ldw     RT'.Lpmain(%r1), %r26
 100         ldw     0(%r26),%r26
 101         /* void (*init) (void) (4th argument) */
 102         addil   LT'.Lp__libc_csu_init, %r19
 103         ldw     RT'.Lp__libc_csu_init(%r1), %r23
 104         ldw     0(%r23), %r23
 105         /* void (*fini) (void) (5th argument) */
 106         addil   LT'.Lp__libc_csu_fini, %r19
 107         ldw     RT'.Lp__libc_csu_fini(%r1), %r22
 108         ldw     0(%r22), %r22
 109 #else
 110         /* load main (1st argument) */
 111         ldil    LR'.Lpmain, %r26
 112         ldw     RR'.Lpmain(%r26), %r26
 113         /* void (*init) (void) (4th argument) */
 114         ldil    LR'.Lp__libc_csu_init, %r23
 115         ldw     RR'.Lp__libc_csu_init(%r23), %r23
 116         /* void (*fini) (void) (5th argument) */
 117         ldil    LR'.Lp__libc_csu_fini, %r22
 118         ldw     RR'.Lp__libc_csu_fini(%r22), %r22
 119 #endif
 120         /* Store 5th argument */
 121         stw     %r22, -52(%sp)
 122         /* void *stack_end (7th argument) */
 123         stw     %sp, -60(%sp)
 124
 125         /* load global */
 126         ldil    L%$global$, %dp
 127         ldo     R%$global$(%dp), %dp
 128
 129         bl      __libc_start_main,%r2
 130         nop
 131         /* die horribly if it returned (it shouldn't) */
 132         iitlbp %r0,(%sr0,%r0)
 133         nop
 134
 135         .procend
 136
 137 /* Define a symbol for the first piece of initialized data.  */
 138         .data
 139         .globl __data_start
 140 __data_start:
 141         .long 0
 142         .weak data_start
 143         data_start = __data_start