libgcc/config/arm/crtn.S

   1 #   Copyright (C) 2001-2022 Free Software Foundation, Inc.
   2 #   Written By Nick Clifton
   3 #
   4 # This file is free software; you can redistribute it and/or modify it
   5 # under the terms of the GNU General Public License as published by the
   6 # Free Software Foundation; either version 3, or (at your option) any
   7 # later version.
   8 #
   9 # This file is distributed in the hope that it will be useful, but
  10 # WITHOUT ANY WARRANTY; without even the implied warranty of
  11 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12 # General Public License for more details.
  13 #
  14 # Under Section 7 of GPL version 3, you are granted additional
  15 # permissions described in the GCC Runtime Library Exception, version
  16 # 3.1, as published by the Free Software Foundation.
  17 #
  18 # You should have received a copy of the GNU General Public License and
  19 # a copy of the GCC Runtime Library Exception along with this program;
  20 # see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  21 # <http://www.gnu.org/licenses/>.
  22
  23 /* An executable stack is *not* required for these functions.  */
  24 #if defined(__ELF__) && defined(__linux__)
  25 .section .note.GNU-stack,"",%progbits
  26 .previous
  27 #endif
  28
  29 #ifdef __ARM_EABI__
  30 /* Some attributes that are common to all routines in this file.  */
  31         /* Tag_ABI_align_needed: This code does not require 8-byte
  32            alignment from the caller.  */
  33         /* .eabi_attribute 24, 0  -- default setting.  */
  34         /* Tag_ABI_align_preserved: This code preserves 8-byte
  35            alignment in any callee.  */
  36         .eabi_attribute 25, 1
  37 #endif /* __ARM_EABI__ */
  38
  39 # This file just makes sure that the .fini and .init sections do in
  40 # fact return.  Users may put any desired instructions in those sections.
  41 # This file is the last thing linked into any executable.
  42
  43         # Note - this macro is complemented by the FUNC_START macro
  44         # in crti.S.  If you change this macro you must also change
  45         # that macro match.
  46         #
  47         # Note - we do not try any fancy optimizations of the return
  48         # sequences here, it is just not worth it.  Instead keep things
  49         # simple.  Restore all the save registers, including the link
  50         # register and then perform the correct function return instruction.
  51         # We also save/restore r3 to ensure stack alignment.
  52 .macro FUNC_END
  53 #ifdef __thumb__
  54         .thumb
  55
  56         pop     {r3, r4, r5, r6, r7}
  57         pop     {r3}
  58         mov     lr, r3
  59 #else
  60         .arm
  61
  62         sub     sp, fp, #40
  63         ldmfd   sp, {r4, r5, r6, r7, r8, r9, sl, fp, sp, lr}
  64 #endif
  65
  66 #if defined __THUMB_INTERWORK__ || defined __thumb__
  67         bx      lr
  68 #else
  69         mov     pc, lr
  70 #endif
  71 .endm
  72
  73
  74         .section        ".init"
  75         ;;
  76         FUNC_END
  77
  78         .section        ".fini"
  79         ;;
  80         FUNC_END
  81
  82 # end of crtn.S