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4a3f29e7e4
Implementation wise:
1. Remove the VZEROUPPER as memset_{impl}_unaligned_erms does not
use the L(stosb) label that was previously defined.
2. Don't give the hotpath (fallthrough) to zero size.
Code positioning wise:
Move memset_{chk}_erms to its own file. Leaving it in between the
memset_{impl}_unaligned both adds unnecessary complexity to the
file and wastes space in a relatively hot cache section.
45 lines
1.3 KiB
ArmAsm
45 lines
1.3 KiB
ArmAsm
/* memset implement with rep stosb
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Copyright (C) 2022 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>. */
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#include <sysdep.h>
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#if defined USE_MULTIARCH && IS_IN (libc)
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.text
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ENTRY (__memset_chk_erms)
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cmp %RDX_LP, %RCX_LP
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jb HIDDEN_JUMPTARGET (__chk_fail)
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END (__memset_chk_erms)
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/* Only used to measure performance of REP STOSB. */
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ENTRY (__memset_erms)
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/* Skip zero length. */
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test %RDX_LP, %RDX_LP
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jz L(stosb_return_zero)
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mov %RDX_LP, %RCX_LP
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movzbl %sil, %eax
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mov %RDI_LP, %RDX_LP
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rep stosb
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mov %RDX_LP, %RAX_LP
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ret
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L(stosb_return_zero):
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movq %rdi, %rax
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ret
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END (__memset_erms)
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#endif
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