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dd139897 | 1 | /* Startup code compliant to the ELF Mips ABI. |
2b778ceb | 2 | Copyright (C) 1995-2021 Free Software Foundation, Inc. |
db31c863 | 3 | This file is part of the GNU C Library. |
dd139897 | 4 | |
db31c863 | 5 | The GNU C Library is free software; you can redistribute it and/or |
3214b89b AJ |
6 | modify it under the terms of the GNU Lesser General Public |
7 | License as published by the Free Software Foundation; either | |
8 | version 2.1 of the License, or (at your option) any later version. | |
dd139897 | 9 | |
0bec0145 RM |
10 | In addition to the permissions in the GNU Lesser General Public |
11 | License, the Free Software Foundation gives you unlimited | |
12 | permission to link the compiled version of this file with other | |
13 | programs, and to distribute those programs without any restriction | |
14 | coming from the use of this file. (The GNU Lesser General Public | |
15 | License restrictions do apply in other respects; for example, they | |
16 | cover modification of the file, and distribution when not linked | |
17 | into another program.) | |
18 | ||
19 | Note that people who make modified versions of this file are not | |
20 | obligated to grant this special exception for their modified | |
21 | versions; it is their choice whether to do so. The GNU Lesser | |
22 | General Public License gives permission to release a modified | |
23 | version without this exception; this exception also makes it | |
24 | possible to release a modified version which carries forward this | |
25 | exception. | |
26 | ||
db31c863 UD |
27 | The GNU C Library is distributed in the hope that it will be useful, |
28 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
29 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
3214b89b | 30 | Lesser General Public License for more details. |
dd139897 | 31 | |
3214b89b | 32 | You should have received a copy of the GNU Lesser General Public |
ab84e3ff | 33 | License along with the GNU C Library. If not, see |
5a82c748 | 34 | <https://www.gnu.org/licenses/>. */ |
dd139897 | 35 | |
5c8f22b4 | 36 | #define __ASSEMBLY__ 1 |
5a50d6f5 | 37 | #include <entry.h> |
b8ddf7a1 | 38 | #include <sgidefs.h> |
ca2b264c | 39 | #include <sys/asm.h> |
5a50d6f5 UD |
40 | |
41 | #ifndef ENTRY_POINT | |
42 | #error ENTRY_POINT needs to be defined for start.S on MIPS/ELF. | |
43 | #endif | |
44 | ||
dd139897 UD |
45 | /* This is the canonical entry point, usually the first thing in the text |
46 | segment. The SVR4/Mips ABI (pages 3-31, 3-32) says that when the entry | |
47 | point runs, most registers' values are unspecified, except for: | |
48 | ||
4decd16a | 49 | v0 ($2) Contains a function pointer to be registered with `atexit'. |
db31c863 | 50 | This is how the dynamic linker arranges to have DT_FINI |
dd139897 UD |
51 | functions called for shared libraries that have been loaded |
52 | before this code runs. | |
53 | ||
54 | sp ($29) The stack contains the arguments and environment: | |
db31c863 | 55 | 0(%esp) argc |
dd139897 UD |
56 | 4(%esp) argv[0] |
57 | ... | |
58 | (4*argc)(%esp) NULL | |
59 | (4*(argc+1))(%esp) envp[0] | |
60 | ... | |
61 | NULL | |
62 | ra ($31) The return address register is set to zero so that programs | |
63 | that search backword through stack frames recognize the last | |
64 | stack frame. | |
65 | */ | |
66 | ||
fc16ca32 AJ |
67 | |
68 | /* We need to call: | |
69 | __libc_start_main (int (*main) (int, char **, char **), int argc, | |
70 | char **argv, void (*init) (void), void (*fini) (void), | |
71 | void (*rtld_fini) (void), void *stack_end) | |
72 | */ | |
5556231d | 73 | |
db31c863 | 74 | .text |
5a50d6f5 | 75 | .globl ENTRY_POINT |
13906e12 | 76 | .type ENTRY_POINT,@function |
43301bd3 | 77 | #ifndef __mips16 |
5a50d6f5 | 78 | ENTRY_POINT: |
43301bd3 | 79 | # ifdef __PIC__ |
ca2b264c AO |
80 | SETUP_GPX($0) |
81 | SETUP_GPX64($25,$0) | |
43301bd3 | 82 | # else |
ca2b264c | 83 | PTR_LA $28, _gp /* Setup GP correctly if we're non-PIC. */ |
dd139897 | 84 | move $31, $0 |
43301bd3 | 85 | # endif |
dd139897 | 86 | |
ca2b264c AO |
87 | PTR_LA $4, main /* main */ |
88 | PTR_L $5, 0($29) /* argc */ | |
89 | PTR_ADDIU $6, $29, PTRSIZE /* argv */ | |
5556231d | 90 | |
ca2b264c | 91 | /* Allocate space on the stack for seven arguments (o32 only) |
5556231d | 92 | and make sure the stack is aligned to double words (8 bytes) |
ca2b264c | 93 | on o32 and quad words (16 bytes) on n32 and n64. */ |
5556231d | 94 | |
ca2b264c | 95 | and $29, -2 * SZREG |
43301bd3 | 96 | # if _MIPS_SIM == _ABIO32 |
ca2b264c | 97 | PTR_SUBIU $29, 32 |
43301bd3 | 98 | # endif |
ca2b264c AO |
99 | PTR_LA $7, __libc_csu_init /* init */ |
100 | PTR_LA $8, __libc_csu_fini | |
43301bd3 | 101 | # if _MIPS_SIM == _ABIO32 |
ca2b264c AO |
102 | PTR_S $8, 16($29) /* fini */ |
103 | PTR_S $2, 20($29) /* rtld_fini */ | |
104 | PTR_S $29, 24($29) /* stack_end */ | |
43301bd3 | 105 | # else |
ca2b264c AO |
106 | move $9, $2 /* rtld_fini */ |
107 | move $10, $29 /* stack_end */ | |
43301bd3 | 108 | # endif |
bbe4c142 PJ |
109 | PTR_LA $25, __libc_start_main |
110 | jalr $25 | |
dd139897 UD |
111 | hlt: b hlt /* Crash if somehow it does return. */ |
112 | ||
43301bd3 MR |
113 | #elif _MIPS_SIM == _ABIO32 /* __mips16 */ |
114 | /* MIPS16 entry point. */ | |
115 | .set mips16 | |
116 | ENTRY_POINT: | |
117 | # ifdef __PIC__ | |
118 | li $3, %hi(_gp_disp) | |
119 | addiu $4, $pc, %lo(_gp_disp) | |
120 | sll $3, 16 | |
121 | addu $3, $4 | |
122 | move $gp, $3 | |
123 | # else | |
124 | li $3, %hi(_gp) | |
125 | sll $3, 16 | |
126 | addiu $3, %lo(_gp) | |
127 | move $gp, $3 | |
128 | # endif | |
129 | /* Tie end of stack frames. */ | |
130 | li $4, 0 | |
131 | move $31, $4 | |
132 | /* Create new SP value in $7, including alignment. */ | |
133 | li $4, 2 * SZREG | |
134 | neg $4, $4 | |
135 | move $7, $sp | |
136 | and $7, $4 | |
137 | addiu $7, -32 | |
138 | /* Load arguments with original SP. */ | |
139 | lw $5, 0($sp) | |
140 | addiu $6, $sp, PTRSIZE | |
141 | /* Update SP. */ | |
142 | move $sp, $7 | |
143 | /* Lay out last arguments, and call __libc_start_main(). */ | |
144 | # ifdef __PIC__ | |
145 | sw $7, 24($sp) /* stack_end */ | |
146 | lw $4, %got(__libc_csu_fini)($3) | |
147 | lw $7, %got(__libc_csu_init)($3) /* init */ | |
148 | sw $4, 16($sp) /* fini */ | |
149 | lw $4, %got(main)($3) /* main */ | |
150 | lw $3, %call16(__libc_start_main)($3) | |
151 | sw $2, 20($sp) /* rtld_fini */ | |
152 | move $25, $3 | |
153 | jalr $3 | |
154 | # else | |
155 | lw $4, 1f | |
156 | sw $7, 24($sp) /* stack_end */ | |
157 | lw $7, 2f /* init */ | |
158 | sw $4, 16($sp) /* fini */ | |
159 | lw $4, 3f /* main */ | |
160 | sw $2, 20($sp) /* rtld_fini */ | |
bbe4c142 PJ |
161 | /* Load and call __libc_start_main(). */ |
162 | lw $3, 4f | |
163 | jalr $3 | |
43301bd3 MR |
164 | # endif |
165 | hlt: b hlt /* Crash if somehow it does return. */ | |
166 | # ifndef __PIC__ | |
167 | .align 2 | |
168 | 1: .word __libc_csu_fini | |
169 | 2: .word __libc_csu_init | |
170 | 3: .word main | |
bbe4c142 | 171 | 4: .word __libc_start_main |
43301bd3 MR |
172 | # endif |
173 | ||
174 | #else /* __mips16 && _MIPS_SIM != _ABIO32 */ | |
175 | # error "MIPS16 support for N32/N64 not implemented" | |
176 | ||
177 | #endif /* __mips16 */ | |
178 | ||
dd139897 UD |
179 | /* Define a symbol for the first piece of initialized data. */ |
180 | .data | |
181 | .globl __data_start | |
182 | __data_start: | |
5a50d6f5 | 183 | .long 0 |
dd139897 UD |
184 | .weak data_start |
185 | data_start = __data_start |