| 1 | /* start, OpenRISC version. |
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| 2 | Copyright (C) 2022 Free Software Foundation, Inc. |
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| 3 | This file is part of the GNU C Library. |
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| 4 | |
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| 5 | The GNU C Library is free software; you can redistribute it and/or |
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| 6 | modify it under the terms of the GNU Lesser General Public |
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| 7 | License as published by the Free Software Foundation; either |
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| 8 | version 2.1 of the License, or (at your option) any later version. |
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| 9 | |
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| 10 | The GNU C Library is distributed in the hope that it will be useful, |
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| 11 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
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| 12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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| 13 | Lesser General Public License for more details. |
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| 14 | |
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| 15 | You should have received a copy of the GNU Lesser General Public |
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| 16 | License along with the GNU C Library; if not, write to the Free |
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| 17 | Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA |
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| 18 | 02111-1307 USA. */ |
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| 19 | |
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| 20 | /* This is the canonical entry point, usually the first thing in the text |
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| 21 | segment. |
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| 22 | |
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| 23 | sp The stack contains the arguments and environment: |
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| 24 | 0(sp) argc |
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| 25 | 4(sp) argv[0] |
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| 26 | ... |
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| 27 | (4*argc)(sp) NULL |
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| 28 | (4*(argc+1))(sp) envp[0] |
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| 29 | ... |
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| 30 | NULL |
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| 31 | */ |
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| 32 | |
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| 33 | #define __ASSEMBLY__ |
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| 34 | #include <sysdep.h> |
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| 35 | #include <entry.h> |
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| 36 | |
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| 37 | ENTRY (ENTRY_POINT) |
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| 38 | |
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| 39 | /* Setup Arguments to the __libc_start_main function. */ |
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| 40 | |
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| 41 | /* Take values for argc and argv off the stack. |
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| 42 | These will be passed as arguments two and three to main |
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| 43 | and thus go in registers r4 and r5, respectively. */ |
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| 44 | l.lwz r4, 0(r1) |
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| 45 | l.addi r5, r1, 4 |
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| 46 | |
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| 47 | /* Pass in rtld_fini from dl-start.S. */ |
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| 48 | l.or r8, r3, r3 |
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| 49 | |
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| 50 | #ifdef PIC |
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| 51 | /* Obtain a pointer to .got in r16 */ |
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| 52 | l.jal 0x8 |
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| 53 | l.movhi r16, gotpchi(_GLOBAL_OFFSET_TABLE_-4) |
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| 54 | l.ori r16, r16, gotpclo(_GLOBAL_OFFSET_TABLE_+0) |
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| 55 | l.add r16, r16, r9 |
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| 56 | |
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| 57 | /* Pass in the the main symbol. */ |
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| 58 | l.lwz r3, got(main)(r16) |
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| 59 | #else |
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| 60 | /* Pass in the the main symbol. */ |
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| 61 | l.movhi r3, hi(main) |
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| 62 | l.ori r3, r3, lo(main) |
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| 63 | #endif |
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| 64 | /* Used to be init and fini. */ |
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| 65 | l.movhi r6, 0x0 |
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| 66 | l.movhi r7, 0x0 |
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| 67 | |
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| 68 | /* Push stack limit onto the stack. |
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| 69 | This provides the highest stack address to user code (as stack grows |
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| 70 | downwards. |
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| 71 | This is the seventh argument to __libc_start_main and thus needs to |
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| 72 | be passed on the stack. */ |
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| 73 | l.sw -4(r1), r1 |
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| 74 | |
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| 75 | /* Adjust stack to account for a total of 7 args (i.e. the last one is |
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| 76 | on the stack. */ |
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| 77 | l.addi r1, r1, -4 |
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| 78 | |
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| 79 | /* Clear the frame pointer and link register since this is the |
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| 80 | outermost frame. */ |
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| 81 | l.movhi r2, 0x0 |
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| 82 | l.movhi r9, 0x0 |
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| 83 | |
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| 84 | /* Let the libc call main and exit with its return code. */ |
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| 85 | #ifdef PIC |
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| 86 | l.j plt(__libc_start_main) |
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| 87 | #else |
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| 88 | l.j __libc_start_main |
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| 89 | #endif |
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| 90 | l.nop |
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| 91 | END (ENTRY_POINT) |
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| 92 | |
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| 93 | /* Define a symbol for the first piece of initialized data. */ |
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| 94 | .data |
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| 95 | .globl __data_start |
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| 96 | __data_start: |
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| 97 | .long 0 |
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| 98 | .weak data_start |
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| 99 | data_start = __data_start |
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| 100 | |
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