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a23bd00f9d
This started as a trivial change to Anton's rawmemchr. I got carried away. This is a hybrid between P8's asympotically faster 64B checks with extremely efficient small string checks e.g <64B (and sometimes a little bit more depending on alignment). The second trick is to align to 64B by running a 48B checking loop 16B at a time until we naturally align to 64B (i.e checking 48/96/144 bytes/iteration based on the alignment after the first 5 comparisons). This allieviates the need to check page boundaries. Finally, explicly use the P7 strlen with the runtime loader when building P9. We need to be cautious about vector/vsx extensions here on P9 only builds.
50 lines
1.8 KiB
C
50 lines
1.8 KiB
C
/* Multiple versions of strlen. PowerPC64 version.
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Copyright (C) 2013-2020 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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#if defined SHARED && IS_IN (libc)
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/* Redefine strlen so that the compiler won't complain about the type
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mismatch with the IFUNC selector in strong_alias, below. */
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# undef strlen
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# define strlen __redirect_strlen
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# include <string.h>
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# include <shlib-compat.h>
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# include "init-arch.h"
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extern __typeof (__redirect_strlen) __libc_strlen;
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extern __typeof (__redirect_strlen) __strlen_ppc attribute_hidden;
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extern __typeof (__redirect_strlen) __strlen_power7 attribute_hidden;
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extern __typeof (__redirect_strlen) __strlen_power8 attribute_hidden;
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extern __typeof (__redirect_strlen) __strlen_power9 attribute_hidden;
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libc_ifunc (__libc_strlen,
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# ifdef __LITTLE_ENDIAN__
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(hwcap2 & PPC_FEATURE2_ARCH_3_00)
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? __strlen_power9 :
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# endif
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(hwcap2 & PPC_FEATURE2_ARCH_2_07)
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? __strlen_power8 :
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(hwcap & PPC_FEATURE_HAS_VSX)
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? __strlen_power7
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: __strlen_ppc);
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#undef strlen
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strong_alias (__libc_strlen, strlen)
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libc_hidden_ver (__libc_strlen, strlen)
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#endif
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