lh | 9ed821d | 2023-04-07 01:36:19 -0700 | [diff] [blame^] | 1 | /* Startup code for SH & ELF. |
| 2 | Copyright (C) 1999-2015 Free Software Foundation, Inc. |
| 3 | This file is part of the GNU C Library. |
| 4 | |
| 5 | The GNU C Library is free software; you can redistribute it and/or |
| 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. |
| 9 | |
| 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 | |
| 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 |
| 30 | Lesser General Public License for more details. |
| 31 | |
| 32 | You should have received a copy of the GNU Lesser General Public |
| 33 | License along with the GNU C Library; if not, see |
| 34 | <http://www.gnu.org/licenses/>. */ |
| 35 | |
| 36 | /* This is the canonical entry point, usually the first thing in the text |
| 37 | segment. |
| 38 | |
| 39 | Note that the code in the .init section has already been run. |
| 40 | This includes _init and _libc_init |
| 41 | |
| 42 | |
| 43 | At this entry point, most registers' values are unspecified, except: |
| 44 | |
| 45 | r4 Contains a function pointer to be registered with `atexit'. |
| 46 | This is how the dynamic linker arranges to have DT_FINI |
| 47 | functions called for shared libraries that have been loaded |
| 48 | before this code runs. |
| 49 | |
| 50 | sp The stack contains the arguments and environment: |
| 51 | 0(sp) argc |
| 52 | 4(sp) argv[0] |
| 53 | ... |
| 54 | (4*argc)(sp) NULL |
| 55 | (4*(argc+1))(sp) envp[0] |
| 56 | ... |
| 57 | NULL |
| 58 | */ |
| 59 | |
| 60 | .text |
| 61 | .globl _start |
| 62 | .type _start,@function |
| 63 | _start: |
| 64 | /* Clear the frame pointer since this is the outermost frame. */ |
| 65 | mov #0, r14 |
| 66 | |
| 67 | /* Pop argc off the stack and save a pointer to argv */ |
| 68 | mov.l @r15+,r5 |
| 69 | mov r15, r6 |
| 70 | |
| 71 | /* Push the last arguments to main() onto the stack */ |
| 72 | mov.l r4,@-r15 |
| 73 | mov.l L_fini,r0 |
| 74 | mov.l r0,@-r15 |
| 75 | |
| 76 | /* Set up the other arguments for main() that go in registers */ |
| 77 | mov.l L_main,r4 |
| 78 | mov.l L_init,r7 |
| 79 | |
| 80 | /* __libc_start_main (main, argc, argv, init, fini, rtld_fini) */ |
| 81 | |
| 82 | /* Let the libc call main and exit with its return code. */ |
| 83 | mov.l L_libc_start_main,r1 |
| 84 | jsr @r1 |
| 85 | nop |
| 86 | /* should never get here....*/ |
| 87 | mov.l L_abort,r1 |
| 88 | jsr @r1 |
| 89 | nop |
| 90 | .align 2 |
| 91 | L_main: |
| 92 | .long main |
| 93 | L_init: |
| 94 | .long __libc_csu_init |
| 95 | L_fini: |
| 96 | .long __libc_csu_fini |
| 97 | L_libc_start_main: |
| 98 | .long __libc_start_main |
| 99 | L_abort: |
| 100 | .long abort |
| 101 | /* Define a symbol for the first piece of initialized data. */ |
| 102 | .data |
| 103 | .globl __data_start |
| 104 | __data_start: |
| 105 | .long 0 |
| 106 | .weak data_start |
| 107 | data_start = __data_start |
| 108 | .global __fpscr_values |
| 109 | __fpscr_values: |
| 110 | .long 0 |
| 111 | .long 0x80000 |