ELF startup code for Arm.

diff --git a/sysdeps/arm/elf/start.S b/sysdeps/arm/elf/start.S
new file mode 100644 (file)
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+++ b/sysdeps/arm/elf/start.S
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+/* Startup code for ARM & ELF
+   Copyright (C) 1995, 1996, 1997, 1998 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 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., 59 Temple Place - Suite 330,
+   Boston, MA 02111-1307, USA.  */
+
+/* This is the canonical entry point, usually the first thing in the text
+   segment.
+
+       Note that the code in the .init section has already been run.
+       This includes _init and _libc_init
+
+
+       At this entry point, most registers' values are unspecified, except for:
+
+   r0          Contains a function pointer to be registered with `atexit'.
+               This is how the dynamic linker arranges to have DT_FINI
+               functions called for shared libraries that have been loaded
+               before this code runs.
+
+   sp          The stack contains the arguments and environment:
+               0(%esp)                 argc
+               4(%esp)                 argv[0]
+               ...
+               (4*argc)(%esp)          NULL
+               (4*(argc+1))(%esp)      envp[0]
+               ...
+                                       NULL
+*/
+
+       .text
+       .globl _start
+_start:
+       /* Clear the frame pointer.  The Intel ABI suggests this be done,
+               to mark the outermost frame obviously. This seems like a
+               sensible thing to do  */
+       mov fp, #0
+
+       /* r0 contains the address of the shared library termination
+          function, which we will register with `atexit' to be called by
+          `exit'.  I suspect that on some systems, and when statically
+          linked, this will not be set by anything to any function
+          pointer; hopefully it will be zero so we don't try to call
+          random pointers.  */
+       cmp r0,#0
+       blne atexit(PLT)
+
+       /* Do essential libc initialization.  In statically linked
+          programs under the GNU Hurd, this is what sets up the
+          arguments on the stack for the code below. For dyn-link
+          programs, this has been run already, in the .init code. */
+#ifndef PIC
+       bl __libc_init_first
+
+       /* Extract the arguments and environment as encoded on the stack
+          and set up the arguments for `main': argc, argv, envp.  */
+       ldr r0,[sp]
+       add r1,sp,#4
+       add r2,r1,r0,lsl #2
+       add r2,r2,#4
+       /* save a copy of envp while we have it */
+       ldr r3,L_environ
+       str r2,[r3]
+
+       /* Call `_init', which is the entry point to our own `.init'
+          section; and register with `atexit' to have `exit' call
+          `_fini', which is the entry point to our own `.fini' section.  */
+       bl _init
+       ldr r0,L_fini
+       bl atexit
+       b L_pfini
+
+L_fini:        .word _fini
+L_environ: .word _environ
+L_pfini:
+#endif
+       /* rebuild the arg list for main() */
+       ldr r0,[sp]
+       add r1,sp,#4
+       add r2,r1,r0,lsl #2
+       add r2,r2,#4
+
+       /* Call the user's main function, and exit with its value.  */
+       bl main
+       bl exit
+       /* should never get here....*/
+       bl abort
+
+
+/* Define a symbol for the first piece of initialized data.  */
+       .data
+       .globl __data_start
+__data_start:
+       .long 0
+       .weak data_start
+       data_start = __data_start