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96 lines
2.9 KiB
ArmAsm
96 lines
2.9 KiB
ArmAsm
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/* Startup code compliant to the ELF s390 ABI.
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Copyright (C) 2000 Free Software Foundation, Inc.
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Contributed by Martin Schwidefsky (schwidefsky@de.ibm.com).
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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 Library General Public License as
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published by the Free Software Foundation; either version 2 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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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with the GNU C Library; see the file COPYING.LIB. If not,
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write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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Boston, MA 02111-1307, USA. */
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/*
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This is the canonical entry point, usually the first thing in the text
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segment. Most registers' values are unspecified, except for:
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%r14 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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%r15 The stack contains the arguments and environment:
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0(%r15) argc
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4(%r15) argv[0]
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...
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(4*argc)(%r15) NULL
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(4*(argc+1))(%r15) 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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_start:
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/* Setup pointer to literal pool of _start */
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basr %r13,0
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.L0: ahi %r13,.Llit-.L0
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/* load argc and argv from stack */
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la %r4,4(%r15) # get argv
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l %r3,0(%r15) # get argc
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/* align the stack to a double word boundary */
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lhi %r0,-8
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nr %r15,%r0
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/* Setup a stack frame and a parameter area */
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ahi %r15,-104 # make room on stack
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xc 0(4,%r15),0(%r15) # clear back-chain
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/* set up arguments for __libc_start_main:
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main, argc, argv, envp, _init, _fini, rtld_fini, stack_end
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Note that envp will be determined later in __libc_start_main
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*/
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stm %r14,%r15,96(%r15) # store rtld_fini/stack_end to parameter area
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la %r7,96(%r15)
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l %r6,.L2-.Llit(%r13) # load pointer to _fini
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l %r5,.L1-.Llit(%r13) # load pointer to _init
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l %r2,.L3-.Llit(%r13) # load pointer to main
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/* ok, now branch to the libc main routine */
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l %r1,.L4-.Llit(%r13)
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basr %r14,%r1
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/* crash if __libc_start_main returns */
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.word 0
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.Llit:
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.L1: .long _init
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.L2: .long _fini
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.L3: .long main
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.L4: .long __libc_start_main
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/* FIXME: FPU flags or what ?!? */
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.section .rodata
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.globl _fp_hw
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.long 3
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.size _fp_hw, 4
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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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