| 1 | /* memcpy with REP MOVSB/STOSB |
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| 2 | Copyright (C) 2015-2024 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, see |
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| 17 | <https://www.gnu.org/licenses/>. */ |
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| 18 | |
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| 19 | #include <sysdep.h> |
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| 20 | #include "asm-syntax.h" |
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| 21 | |
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| 22 | #ifndef MEMCPY |
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| 23 | # define MEMCPY memcpy |
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| 24 | # define MEMCPY_CHK __memcpy_chk |
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| 25 | #endif |
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| 26 | |
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| 27 | #define STR1 12 |
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| 28 | #define STR2 STR1+4 |
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| 29 | #define N STR2+4 |
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| 30 | |
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| 31 | #define CFI_PUSH(REG) \ |
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| 32 | cfi_adjust_cfa_offset (4); \ |
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| 33 | cfi_rel_offset (REG, 0) |
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| 34 | |
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| 35 | #define CFI_POP(REG) \ |
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| 36 | cfi_adjust_cfa_offset (-4); \ |
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| 37 | cfi_restore (REG) |
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| 38 | |
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| 39 | #define PUSH(REG) pushl REG; CFI_PUSH (REG) |
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| 40 | #define POP(REG) popl REG; CFI_POP (REG) |
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| 41 | |
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| 42 | .text |
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| 43 | #if defined SHARED && IS_IN (libc) |
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| 44 | ENTRY (MEMCPY_CHK) |
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| 45 | movl 12(%esp), %eax |
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| 46 | cmpl %eax, 16(%esp) |
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| 47 | jb HIDDEN_JUMPTARGET (__chk_fail) |
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| 48 | END (MEMCPY_CHK) |
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| 49 | libc_hidden_builtin_def (MEMCPY_CHK) |
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| 50 | #endif |
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| 51 | ENTRY (MEMCPY) |
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| 52 | PUSH (%esi) |
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| 53 | PUSH (%edi) |
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| 54 | movl N(%esp), %ecx |
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| 55 | movl STR1(%esp), %edi |
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| 56 | movl STR2(%esp), %esi |
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| 57 | mov %edi, %eax |
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| 58 | #ifdef USE_AS_MEMPCPY |
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| 59 | add %ecx, %eax |
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| 60 | #endif |
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| 61 | |
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| 62 | #ifdef USE_AS_MEMMOVE |
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| 63 | cmp %esi, %edi |
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| 64 | ja L(copy_backward) |
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| 65 | je L(bwd_write_0bytes) |
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| 66 | #endif |
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| 67 | |
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| 68 | rep movsb |
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| 69 | POP (%edi) |
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| 70 | POP (%esi) |
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| 71 | ret |
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| 72 | |
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| 73 | #ifdef USE_AS_MEMMOVE |
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| 74 | L(copy_backward): |
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| 75 | lea -1(%edi,%ecx), %edi |
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| 76 | lea -1(%esi,%ecx), %esi |
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| 77 | std |
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| 78 | rep movsb |
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| 79 | cld |
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| 80 | L(bwd_write_0bytes): |
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| 81 | POP (%edi) |
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| 82 | POP (%esi) |
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| 83 | ret |
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| 84 | #endif |
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| 85 | |
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| 86 | END (MEMCPY) |
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| 87 | |
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| 88 | libc_hidden_builtin_def (MEMCPY) |
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| 89 | |
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