sysdeps/unix/sysv/linux/i386/brk.S

   1 /* Copyright (C) 1991, 1992, 1993, 1995 Free Software Foundation, Inc.
   2 This file is part of the GNU C Library.
   3
   4 The GNU C Library is free software; you can redistribute it and/or
   5 modify it under the terms of the GNU Library General Public License as
   6 published by the Free Software Foundation; either version 2 of the
   7 License, or (at your option) any later version.
   8
   9 The GNU C Library is distributed in the hope that it will be useful,
  10 but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12 Library General Public License for more details.
  13
  14 You should have received a copy of the GNU Library General Public
  15 License along with the GNU C Library; see the file COPYING.LIB.  If
  16 not, write to the Free Software Foundation, Inc., 675 Mass Ave,
  17 Cambridge, MA 02139, USA.  */
  18
  19 #include <sysdep.h>
  20
  21 .data
  22 .globl C_SYMBOL_NAME(__curbrk)
  23 C_LABEL(__curbrk)
  24 #ifdef PIC
  25         .long 0
  26 #else
  27 # ifdef HAVE_GNU_LD
  28         .long C_SYMBOL_NAME(_end)
  29 # else
  30         .long C_SYMBOL_NAME(end)
  31 # endif
  32 #endif
  33
  34 .text
  35
  36         SYSCALL_ERROR_HANDLER
  37 ENTRY (__brk)
  38         movl %ebx, %edx
  39         movl $SYS_ify(brk), %eax
  40         movl 4(%esp), %ebx
  41         int $0x80
  42         movl %edx, %ebx
  43
  44         cmpl 4(%esp), %eax
  45         jne syscall_error
  46
  47 #ifdef PIC
  48         /* Standard PIC nonsense to store into `__curbrk' through the GOT.  */
  49         call here
  50 here:   popl %ecx
  51         addl $_GLOBAL_OFFSET_TABLE_+[.-here], %ecx
  52         movl C_SYMBOL_NAME(__curbrk@GOT)(%ecx), %ecx
  53         movl %eax, (%ecx)
  54 #else
  55         movl %eax, C_SYMBOL_NAME(__curbrk)
  56 #endif
  57         xorl %eax, %eax
  58         ret
  59
  60 weak_alias (__brk, brk)