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/* Startup code compliant to the ELF Mips ABI.
Copyright (C) 1995, 1997, 2000, 2001 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, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
#define __ASSEMBLY__ 1
#include <entry.h>
#ifndef ENTRY_POINT
#error ENTRY_POINT needs to be defined for start.S on MIPS/ELF.
#endif
/* This is the canonical entry point, usually the first thing in the text
segment. The SVR4/Mips ABI (pages 3-31, 3-32) says that when the entry
point runs, most registers' values are unspecified, except for:
v0 ($2) 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 ($29) 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
ra ($31) The return address register is set to zero so that programs
that search backword through stack frames recognize the last
stack frame.
*/
/* We need to call:
__libc_start_main (int (*main) (int, char **, char **), int argc,
char **argv, void (*init) (void), void (*fini) (void),
void (*rtld_fini) (void), void *stack_end)
*/
#ifdef __PIC__
/* A macro to (re)initialize gp. We can get the run time address of 0f in
ra ($31) by blezal instruction. In this early phase, we can't save gp
in stack and .cprestore doesn't work properly. So we set gp by using
this macro. */
#define SET_GP \
.set noreorder; \
bltzal $0,0f; \
nop; \
0: .cpload $31; \
.set reorder;
#endif
.text
.globl ENTRY_POINT
.type ENTRY_POINT,@function
ENTRY_POINT:
#ifdef __PIC__
SET_GP
#endif
move $31, $0
la $4, main /* main */
lw $5, 0($29) /* argc */
addu $6, $29, 4 /* argv */
/* Allocate space on the stack for seven arguments and make sure
the stack is aligned to double words (8 bytes). */
and $29, 0xfffffff8
subu $29, 32
la $7, _init /* init */
la $8, _fini
sw $8, 16($29) /* fini */
sw $2, 20($29) /* rtld_fini */
sw $29, 24($29) /* stack_end */
jal __libc_start_main
hlt: b hlt /* Crash if somehow it does return. */
/* 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
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