| 1 | /* memset implement with rep stosb |
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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 (__memset_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 (__memset_chk_erms) |
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| 28 | |
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| 29 | /* Only used to measure performance of REP STOSB. */ |
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| 30 | ENTRY (__memset_erms) |
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| 31 | /* Skip zero length. */ |
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| 32 | test %RDX_LP, %RDX_LP |
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| 33 | jz L(stosb_return_zero) |
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| 34 | mov %RDX_LP, %RCX_LP |
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| 35 | movzbl %sil, %eax |
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| 36 | mov %RDI_LP, %RDX_LP |
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| 37 | rep stosb |
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| 38 | mov %RDX_LP, %RAX_LP |
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| 39 | ret |
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| 40 | L(stosb_return_zero): |
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| 41 | movq %rdi, %rax |
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| 42 | ret |
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| 43 | END (__memset_erms) |
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| 44 | #endif |
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| 45 | |
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