mirror of
https://sourceware.org/git/glibc.git
synced 2024-11-30 00:31:08 +00:00
149 lines
4.2 KiB
ArmAsm
149 lines
4.2 KiB
ArmAsm
/* Startup code for ARM & ELF
|
|
Copyright (C) 1995-2012 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 Lesser General Public
|
|
License as published by the Free Software Foundation; either
|
|
version 2.1 of the License, or (at your option) any later version.
|
|
|
|
In addition to the permissions in the GNU Lesser General Public
|
|
License, the Free Software Foundation gives you unlimited
|
|
permission to link the compiled version of this file with other
|
|
programs, and to distribute those programs without any restriction
|
|
coming from the use of this file. (The GNU Lesser General Public
|
|
License restrictions do apply in other respects; for example, they
|
|
cover modification of the file, and distribution when not linked
|
|
into another program.)
|
|
|
|
Note that people who make modified versions of this file are not
|
|
obligated to grant this special exception for their modified
|
|
versions; it is their choice whether to do so. The GNU Lesser
|
|
General Public License gives permission to release a modified
|
|
version without this exception; this exception also makes it
|
|
possible to release a modified version which carries forward this
|
|
exception.
|
|
|
|
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
|
|
Lesser General Public License for more details.
|
|
|
|
You should have received a copy of the GNU Lesser General Public
|
|
License along with the GNU C Library. If not, see
|
|
<http://www.gnu.org/licenses/>. */
|
|
|
|
/* 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:
|
|
|
|
a1 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(sp) argc
|
|
4(sp) argv[0]
|
|
...
|
|
(4*argc)(sp) NULL
|
|
(4*(argc+1))(sp) envp[0]
|
|
...
|
|
NULL
|
|
*/
|
|
|
|
/* Tag_ABI_align8_preserved: This code preserves 8-byte
|
|
alignment in any callee. */
|
|
.eabi_attribute 25, 1
|
|
/* Tag_ABI_align8_needed: This code may require 8-byte alignment from
|
|
the caller. */
|
|
.eabi_attribute 24, 1
|
|
|
|
#if defined(__thumb2__)
|
|
.thumb
|
|
.syntax unified
|
|
#endif
|
|
|
|
.text
|
|
.globl _start
|
|
.type _start,#function
|
|
_start:
|
|
/* Protect against unhandled exceptions. */
|
|
.fnstart
|
|
/* Clear the frame pointer and link register since this is the outermost frame. */
|
|
mov fp, #0
|
|
mov lr, #0
|
|
|
|
/* Pop argc off the stack and save a pointer to argv */
|
|
ldr a2, [sp], #4
|
|
mov a3, sp
|
|
|
|
/* Push stack limit */
|
|
str a3, [sp, #-4]!
|
|
|
|
/* Push rtld_fini */
|
|
str a1, [sp, #-4]!
|
|
|
|
#ifdef SHARED
|
|
ldr sl, .L_GOT
|
|
adr a4, .L_GOT
|
|
add sl, sl, a4
|
|
|
|
ldr ip, .L_GOT+4 /* __libc_csu_fini */
|
|
ldr ip, [sl, ip]
|
|
|
|
str ip, [sp, #-4]! /* Push __libc_csu_fini */
|
|
|
|
ldr a4, .L_GOT+8 /* __libc_csu_init */
|
|
ldr a4, [sl, a4]
|
|
|
|
ldr a1, .L_GOT+12 /* main */
|
|
ldr a1, [sl, a1]
|
|
|
|
/* __libc_start_main (main, argc, argv, init, fini, rtld_fini, stack_end) */
|
|
/* Let the libc call main and exit with its return code. */
|
|
bl __libc_start_main(PLT)
|
|
#else
|
|
/* Fetch address of __libc_csu_fini */
|
|
ldr ip, =__libc_csu_fini
|
|
|
|
/* Push __libc_csu_fini */
|
|
str ip, [sp, #-4]!
|
|
|
|
/* Set up the other arguments in registers */
|
|
ldr a1, =main
|
|
ldr a4, =__libc_csu_init
|
|
|
|
/* __libc_start_main (main, argc, argv, init, fini, rtld_fini, stack_end) */
|
|
/* Let the libc call main and exit with its return code. */
|
|
bl __libc_start_main
|
|
#endif
|
|
|
|
/* should never get here....*/
|
|
bl abort
|
|
|
|
#ifdef SHARED
|
|
.align 2
|
|
.L_GOT:
|
|
.word _GLOBAL_OFFSET_TABLE_ - .L_GOT
|
|
.word __libc_csu_fini(GOT)
|
|
.word __libc_csu_init(GOT)
|
|
.word main(GOT)
|
|
#endif
|
|
|
|
.cantunwind
|
|
.fnend
|
|
|
|
/* 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
|