diff options
Diffstat (limited to 'sysdeps/i386/elf/start.S')
| -rw-r--r-- | sysdeps/i386/elf/start.S | 51 |
1 files changed, 29 insertions, 22 deletions
diff --git a/sysdeps/i386/elf/start.S b/sysdeps/i386/elf/start.S index c5796e8db9..53e324b91b 100644 --- a/sysdeps/i386/elf/start.S +++ b/sysdeps/i386/elf/start.S @@ -1,21 +1,21 @@ /* Startup code compliant to the ELF i386 ABI. -Copyright (C) 1995 Free Software Foundation, Inc. -This file is part of the GNU C Library. + Copyright (C) 1995, 1996, 1997 Free Software Foundation, Inc. + This file is part of the GNU C Library. -The GNU C Library is free software; you can redistribute it and/or -modify it under the terms of the GNU Library General Public License as -published by the Free Software Foundation; either version 2 of the -License, or (at your option) any later version. + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Library General Public License as + published by the Free Software Foundation; either version 2 of the + License, or (at your option) any later version. -The GNU C Library is distributed in the hope that it will be useful, -but WITHOUT ANY WARRANTY; without even the implied warranty of -MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU -Library General Public License for more details. + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Library General Public License for more details. -You should have received a copy of the GNU Library General Public -License along with the GNU C Library; see the file COPYING.LIB. If -not, write to the Free Software Foundation, Inc., 675 Mass Ave, -Cambridge, MA 02139, USA. */ + You should have received a copy of the GNU Library General Public + License along with the GNU C Library; see the file COPYING.LIB. If not, + write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, + Boston, MA 02111-1307, USA. */ /* This is the canonical entry point, usually the first thing in the text segment. The SVR4/i386 ABI (pages 3-31, 3-32) says that when the entry @@ -36,12 +36,12 @@ Cambridge, MA 02139, USA. */ NULL */ - .text + .text .globl _start _start: /* Clear the frame pointer. The ABI suggests this be done, to mark the outermost frame obviously. */ - movl $0, %ebp + xorl %ebp, %ebp /* %edx contains the address of the shared library termination function, which we will register with `atexit' to be called by @@ -53,7 +53,8 @@ _start: jz nofini pushl %edx call atexit - addl $4, %esp + popl %eax /* Pop value to unused register to remove + argument from stack. */ nofini: /* Do essential libc initialization. In statically linked @@ -66,9 +67,15 @@ nofini: popl %esi /* Pop the argument count. */ leal 4(%esp,%esi,4), %eax /* envp = &argv[argc + 1] */ movl %eax, _environ /* Store it in the global variable. */ + movl %esp, %edx /* argv starts just at the current stack top.*/ + + /* Before pushing the arguments align the stack to a double word + boundary to avoid penalties from misaligned accesses. Thanks + to Edward Seidl <seidl@janed.com> for pointing this out. */ + andl $0xfffffff8, %esp + pushl %eax /* Push third argument: envp. */ - leal 4(%esp), %eax /* argv starts just above that word. */ - pushl %eax /* Push second argument: argv. */ + pushl %edx /* Push second argument: argv. */ pushl %esi /* Push first argument: argc. */ /* Call `_init', which is the entry point to our own `.init' @@ -77,13 +84,13 @@ nofini: call _init pushl $_fini call atexit - addl $4, %esp + popl %eax /* Call the user's main function, and exit with its value. */ call main pushl %eax - call exit /* This should never return. */ - hlt /* Crash if somehow it does return. */ + call exit + hlt /* Crash if somehow `exit' does return. */ /* Define a symbol for the first piece of initialized data. */ .data |