2014-01-01 19:03:15 +08:00
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/* Copyright (C) 1995-2014 Free Software Foundation, Inc.
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2012-11-10 01:53:51 +08:00
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public License as
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published by the Free Software Foundation; either version 2.1 of the
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License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library. If not, see
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<http://www.gnu.org/licenses/>. */
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/* This is the canonical entry point, usually the first thing in the text
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segment.
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Note that the code in the .init section has already been run.
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This includes _init and _libc_init
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At this entry point, most registers' values are unspecified, except:
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x0 Contains a function pointer to be registered with `atexit'.
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This is how the dynamic linker arranges to have DT_FINI
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functions called for shared libraries that have been loaded
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before this code runs.
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sp The stack contains the arguments and environment:
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0(sp) argc
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8(sp) argv[0]
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...
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(8*argc)(sp) NULL
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(8*(argc+1))(sp) envp[0]
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...
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NULL
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*/
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.text
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.globl _start
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.type _start,#function
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_start:
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/* Create an initial frame with 0 LR and FP */
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mov x29, #0
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mov x30, #0
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mov x29, sp
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/* Setup rtld_fini in argument register */
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mov x5, x0
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/* Load argc and a pointer to argv */
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ldr x1, [sp, #0]
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add x2, sp, #8
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/* Setup stack limit in argument register */
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mov x6, sp
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#ifdef SHARED
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adrp x0, :got:main
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ldr x0, [x0, #:got_lo12:main]
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adrp x3, :got:__libc_csu_init
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ldr x3, [x3, #:got_lo12:__libc_csu_init]
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adrp x4, :got:__libc_csu_fini
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ldr x4, [x4, #:got_lo12:__libc_csu_fini]
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#else
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/* Set up the other arguments in registers */
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ldr x0, =main
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ldr x3, =__libc_csu_init
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ldr x4, =__libc_csu_fini
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#endif
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/* __libc_start_main (main, argc, argv, init, fini, rtld_fini,
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stack_end) */
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/* Let the libc call main and exit with its return code. */
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bl __libc_start_main
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/* should never get here....*/
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bl abort
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/* Define a symbol for the first piece of initialized data. */
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.data
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.globl __data_start
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__data_start:
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.long 0
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.weak data_start
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data_start = __data_start
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