| 1 | /* memcpy/mempcpy/memmove implement with rep movsb |
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| 2 | Copyright (C) 2022-2024 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 | |
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| 20 | #include <sysdep.h> |
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| 21 | |
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| 22 | #if defined USE_MULTIARCH && IS_IN (libc) |
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| 23 | .text |
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| 24 | ENTRY (__mempcpy_chk_erms) |
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| 25 | cmp %RDX_LP, %RCX_LP |
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| 26 | jb HIDDEN_JUMPTARGET (__chk_fail) |
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| 27 | END (__mempcpy_chk_erms) |
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| 28 | |
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| 29 | /* Only used to measure performance of REP MOVSB. */ |
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| 30 | ENTRY (__mempcpy_erms) |
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| 31 | mov %RDI_LP, %RAX_LP |
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| 32 | /* Skip zero length. */ |
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| 33 | test %RDX_LP, %RDX_LP |
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| 34 | jz 2f |
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| 35 | add %RDX_LP, %RAX_LP |
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| 36 | jmp L(start_movsb) |
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| 37 | END (__mempcpy_erms) |
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| 38 | |
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| 39 | ENTRY (__memmove_chk_erms) |
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| 40 | cmp %RDX_LP, %RCX_LP |
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| 41 | jb HIDDEN_JUMPTARGET (__chk_fail) |
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| 42 | END (__memmove_chk_erms) |
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| 43 | |
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| 44 | ENTRY (__memmove_erms) |
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| 45 | movq %rdi, %rax |
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| 46 | /* Skip zero length. */ |
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| 47 | test %RDX_LP, %RDX_LP |
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| 48 | jz 2f |
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| 49 | L(start_movsb): |
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| 50 | mov %RDX_LP, %RCX_LP |
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| 51 | cmp %RSI_LP, %RDI_LP |
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| 52 | jb 1f |
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| 53 | /* Source == destination is less common. */ |
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| 54 | je 2f |
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| 55 | lea (%rsi,%rcx), %RDX_LP |
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| 56 | cmp %RDX_LP, %RDI_LP |
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| 57 | jb L(movsb_backward) |
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| 58 | 1: |
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| 59 | rep movsb |
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| 60 | 2: |
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| 61 | ret |
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| 62 | L(movsb_backward): |
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| 63 | leaq -1(%rdi,%rcx), %rdi |
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| 64 | leaq -1(%rsi,%rcx), %rsi |
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| 65 | std |
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| 66 | rep movsb |
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| 67 | cld |
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| 68 | ret |
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| 69 | END (__memmove_erms) |
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| 70 | strong_alias (__memmove_erms, __memcpy_erms) |
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| 71 | strong_alias (__memmove_chk_erms, __memcpy_chk_erms) |
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| 72 | #endif |
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| 73 | |
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