| 1 | /* Copy memory block and return pointer to beginning of destination block |
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| 2 | For Intel 80x86, x>=6. |
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| 3 | This file is part of the GNU C Library. |
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| 4 | Copyright (C) 2003-2024 Free Software Foundation, Inc. |
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| 5 | |
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| 6 | The GNU C Library is free software; you can redistribute it and/or |
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| 7 | modify it under the terms of the GNU Lesser General Public |
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| 8 | License as published by the Free Software Foundation; either |
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| 9 | version 2.1 of the License, or (at your option) any later version. |
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| 10 | |
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| 11 | The GNU C Library is distributed in the hope that it will be useful, |
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| 12 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
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| 13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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| 14 | Lesser General Public License for more details. |
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| 15 | |
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| 16 | You should have received a copy of the GNU Lesser General Public |
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| 17 | License along with the GNU C Library; if not, see |
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| 18 | <https://www.gnu.org/licenses/>. */ |
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| 19 | |
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| 20 | #include <sysdep.h> |
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| 21 | #include "asm-syntax.h" |
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| 22 | |
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| 23 | #define PARMS 4+4 /* one spilled register */ |
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| 24 | #define RTN PARMS |
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| 25 | |
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| 26 | .text |
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| 27 | |
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| 28 | #define DEST RTN |
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| 29 | #define SRC DEST+4 |
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| 30 | #define LEN SRC+4 |
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| 31 | |
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| 32 | #if defined PIC && IS_IN (libc) |
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| 33 | ENTRY_CHK (__memmove_chk) |
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| 34 | movl 12(%esp), %eax |
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| 35 | cmpl %eax, 16(%esp) |
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| 36 | jb HIDDEN_JUMPTARGET (__chk_fail) |
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| 37 | END_CHK (__memmove_chk) |
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| 38 | libc_hidden_builtin_def (__memmove_chk) |
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| 39 | #endif |
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| 40 | |
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| 41 | ENTRY (memmove) |
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| 42 | |
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| 43 | pushl %edi |
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| 44 | cfi_adjust_cfa_offset (4) |
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| 45 | |
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| 46 | movl LEN(%esp), %ecx |
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| 47 | movl DEST(%esp), %edi |
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| 48 | cfi_rel_offset (edi, 0) |
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| 49 | movl %esi, %edx |
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| 50 | movl SRC(%esp), %esi |
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| 51 | cfi_register (esi, edx) |
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| 52 | |
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| 53 | movl %edi, %eax |
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| 54 | subl %esi, %eax |
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| 55 | cmpl %eax, %ecx |
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| 56 | ja 3f |
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| 57 | |
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| 58 | cld |
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| 59 | shrl $1, %ecx |
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| 60 | jnc 1f |
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| 61 | movsb |
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| 62 | 1: shrl $1, %ecx |
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| 63 | jnc 2f |
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| 64 | movsw |
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| 65 | 2: rep |
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| 66 | movsl |
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| 67 | movl %edx, %esi |
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| 68 | cfi_restore (esi) |
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| 69 | movl DEST(%esp), %eax |
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| 70 | |
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| 71 | popl %edi |
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| 72 | cfi_adjust_cfa_offset (-4) |
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| 73 | cfi_restore (edi) |
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| 74 | |
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| 75 | ret |
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| 76 | |
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| 77 | cfi_adjust_cfa_offset (4) |
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| 78 | cfi_rel_offset (edi, 0) |
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| 79 | cfi_register (esi, edx) |
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| 80 | |
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| 81 | /* Backward copying. */ |
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| 82 | 3: std |
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| 83 | leal -1(%edi, %ecx), %edi |
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| 84 | leal -1(%esi, %ecx), %esi |
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| 85 | shrl $1, %ecx |
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| 86 | jnc 1f |
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| 87 | movsb |
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| 88 | 1: subl $1, %edi |
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| 89 | subl $1, %esi |
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| 90 | shrl $1, %ecx |
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| 91 | jnc 2f |
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| 92 | movsw |
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| 93 | 2: subl $2, %edi |
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| 94 | subl $2, %esi |
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| 95 | rep |
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| 96 | movsl |
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| 97 | movl %edx, %esi |
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| 98 | cfi_restore (esi) |
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| 99 | movl DEST(%esp), %eax |
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| 100 | |
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| 101 | cld |
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| 102 | popl %edi |
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| 103 | cfi_adjust_cfa_offset (-4) |
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| 104 | cfi_restore (edi) |
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| 105 | |
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| 106 | ret |
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| 107 | END (memmove) |
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| 108 | libc_hidden_builtin_def (memmove) |
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| 109 | |
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