mirror of
git://sourceware.org/git/glibc.git
synced 2024-12-27 04:41:02 +08:00
161 lines
4.4 KiB
ArmAsm
161 lines
4.4 KiB
ArmAsm
/* Startup code compliant to the ELF Mips ABI.
|
|
Copyright (C) 1995, 1997 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 Library General Public License as
|
|
published by the Free Software Foundation; either version 2 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
|
|
Library General Public License for more details.
|
|
|
|
You should have received a copy of the GNU Library General Public
|
|
License along with the GNU C Library; see the file COPYING.LIB. If not,
|
|
write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
|
|
Boston, MA 02111-1307, USA. */
|
|
|
|
#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:
|
|
|
|
v1 ($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.
|
|
*/
|
|
|
|
#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
|
|
ENTRY_POINT:
|
|
#ifdef PIC
|
|
SET_GP
|
|
#endif
|
|
move $31, $0
|
|
|
|
/* $2 contains the address of the shared library termination
|
|
function, which we will register with `atexit' to be called by
|
|
`exit'. I suspect that on some systems, and when statically
|
|
linked, this will not be set by anything to any function
|
|
pointer; hopefully it will be zero so we don't try to call
|
|
random pointers. */
|
|
beq $2, $0, nofini
|
|
move $4, $2
|
|
jal atexit
|
|
#ifdef PIC
|
|
SET_GP
|
|
#endif
|
|
nofini:
|
|
|
|
/* Do essential libc initialization. In statically linked
|
|
programs under the GNU Hurd, this is what sets up the
|
|
arguments on the stack for the code below. Since the argument
|
|
registers (a0 - a3) saved to the first 4 stack entries by
|
|
the prologue of __libc_init_first, we preload them to
|
|
prevent clobbering the stack tops. In Hurd case, stack pointer
|
|
($29) may be VM_MAX_ADDRESS here. If so, we must modify it. */
|
|
#if 0
|
|
jal mach_host_self
|
|
#endif
|
|
li $4, 0x80000000
|
|
bne $29, $4, 1f
|
|
subu $29, 16
|
|
sw $0, 0($29)
|
|
sw $0, 4($29)
|
|
sw $0, 8($29)
|
|
sw $0, 12($29)
|
|
1:
|
|
lw $4, 0($29)
|
|
lw $5, 4($29)
|
|
lw $6, 8($29)
|
|
lw $7, 12($29)
|
|
jal __libc_init_first
|
|
#ifdef PIC
|
|
SET_GP
|
|
#endif
|
|
lw $4, 0($29)
|
|
lw $5, 4($29)
|
|
lw $6, 8($29)
|
|
lw $7, 12($29)
|
|
|
|
/* Call `_init', which is the entry point to our own `.init'
|
|
section; and register with `atexit' to have `exit' call
|
|
`_fini', which is the entry point to our own `.fini' section. */
|
|
jal _init
|
|
#ifdef PIC
|
|
SET_GP
|
|
#endif
|
|
#if (__mips64)
|
|
dla $4, _fini
|
|
#else /* __mips64 */
|
|
la $4, _fini
|
|
#endif /* __mips64 */
|
|
|
|
jal atexit
|
|
#ifdef PIC
|
|
SET_GP
|
|
#endif
|
|
|
|
/* Extract the arguments and environment as encoded on the stack
|
|
and set up the arguments for `main': argc, argv, envp. */
|
|
lw $4, 0($29) /* argc */
|
|
addu $5, $29, 4 /* argv */
|
|
sll $6, $4, 2
|
|
addu $6, $6, 4
|
|
addu $6, $5, $6 /* envp = &argv[argc + 1] */
|
|
|
|
/* Call the user's main function, and exit with its value. */
|
|
jal main
|
|
#ifdef PIC
|
|
SET_GP
|
|
#endif
|
|
move $4, $2
|
|
jal exit /* This should never return. */
|
|
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
|
|
|
|
.comm errno, 4, 4
|
|
#ifdef __ELF__
|
|
.type errno, @object
|
|
#endif
|