glibc/sysdeps/aarch64/start.S
Marcus Shawcroft 75eff3fe90 Relocate AArch64 from ports to libc.
This patch moves the AArch64 port to the main sysdeps hierarchy.  The
move is essentially:

  git mv ports/sysdeps/aarch64 sysdeps/aarch64
  git mv ports/sysdeps/unix/sysv/linux/aarch64 sysdeps/unix/sysv/linux/aarch64

The README is updated and I've updated ChangeLog.aarch64 along the
lines of the ARM move.  The AArch64 build has been tested to confirm
that there were no changes in objdump -dr output or the shared
objects.
2014-02-11 11:36:00 +00:00

94 lines
2.5 KiB
ArmAsm

/* Copyright (C) 1995-2014 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.
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:
x0 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
8(sp) argv[0]
...
(8*argc)(sp) NULL
(8*(argc+1))(sp) envp[0]
...
NULL
*/
.text
.globl _start
.type _start,#function
_start:
/* Create an initial frame with 0 LR and FP */
mov x29, #0
mov x30, #0
mov x29, sp
/* Setup rtld_fini in argument register */
mov x5, x0
/* Load argc and a pointer to argv */
ldr x1, [sp, #0]
add x2, sp, #8
/* Setup stack limit in argument register */
mov x6, sp
#ifdef SHARED
adrp x0, :got:main
ldr x0, [x0, #:got_lo12:main]
adrp x3, :got:__libc_csu_init
ldr x3, [x3, #:got_lo12:__libc_csu_init]
adrp x4, :got:__libc_csu_fini
ldr x4, [x4, #:got_lo12:__libc_csu_fini]
#else
/* Set up the other arguments in registers */
ldr x0, =main
ldr x3, =__libc_csu_init
ldr x4, =__libc_csu_fini
#endif
/* __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
/* 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