1 /* Startup code compliant to the ELF Mips ABI.
2 Copyright (C) 1995, 1997, 2000, 2001, 2002, 2003, 2004
3 Free Software Foundation, Inc.
4 This file is part of the GNU C Library.
6 The GNU C Library is free software; you can redistribute it and/or
7 modify it under the terms of the GNU Lesser General Public
8 License as published by the Free Software Foundation; either
9 version 2.1 of the License, or (at your option) any later version.
11 In addition to the permissions in the GNU Lesser General Public
12 License, the Free Software Foundation gives you unlimited
13 permission to link the compiled version of this file with other
14 programs, and to distribute those programs without any restriction
15 coming from the use of this file. (The GNU Lesser General Public
16 License restrictions do apply in other respects; for example, they
17 cover modification of the file, and distribution when not linked
18 into another program.)
20 Note that people who make modified versions of this file are not
21 obligated to grant this special exception for their modified
22 versions; it is their choice whether to do so. The GNU Lesser
23 General Public License gives permission to release a modified
24 version without this exception; this exception also makes it
25 possible to release a modified version which carries forward this
28 The GNU C Library is distributed in the hope that it will be useful,
29 but WITHOUT ANY WARRANTY; without even the implied warranty of
30 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
31 Lesser General Public License for more details.
33 You should have received a copy of the GNU Lesser General Public
34 License along with the GNU C Library; if not, see
35 <http://www.gnu.org/licenses/>. */
38 #include <sys/regdef.h>
43 /* This is the canonical entry point, usually the first thing in the text
44 segment. The SVR4/Mips ABI (pages 3-31, 3-32) says that when the entry
45 point runs, most registers' values are unspecified, except for:
47 v0 ($2) Contains a function pointer to be registered with `atexit'.
48 This is how the dynamic linker arranges to have DT_FINI
49 functions called for shared libraries that have been loaded
50 before this code runs.
52 sp ($29) The stack contains the arguments and environment:
57 (4*(argc+1))(%esp) envp[0]
60 ra ($31) The return address register is set to zero so that programs
61 that search backword through stack frames recognize the last
67 __uClibc_main (int (*main) (int, char **, char **), int argc,
68 char **argv, void (*init) (void), void (*fini) (void),
69 void (*rtld_fini) (void), void *stack_end)
74 .type __start,@function
77 #ifndef __UCLIBC_CTOR_DTOR__
82 .type __uClibc_main,@function
90 PTR_LA $28, _gp /* Setup GP correctly if we're non-PIC. */
94 PTR_LA $4, main /* main */
95 PTR_L $5, 0($29) /* argc */
96 PTR_ADDIU $6, $29, PTRSIZE /* argv */
98 /* Allocate space on the stack for seven arguments and
99 * make sure the stack is aligned to double words (8 bytes) */
103 #if _MIPS_SIM == _MIPS_SIM_ABI32
106 PTR_LA $7, _init /* init */
108 #if _MIPS_SIM == _MIPS_SIM_ABI32
109 PTR_S $8, 16($29) /* fini */
110 PTR_S $2, 20($29) /* rtld_fini */
111 PTR_S $29, 24($29) /* stack_end */
113 move $9, $2 /* rtld_fini */
114 move $10, $29 /* stack_end */
118 /* Crash if somehow `__uClibc_main' returns anyway. */
120 .size __start,.-__start
123 /* Define a symbol for the first piece of initialized data. */
129 data_start = __data_start