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30891f35fa
We stopped adding "Contributed by" or similar lines in sources in 2012 in favour of git logs and keeping the Contributors section of the glibc manual up to date. Removing these lines makes the license header a bit more consistent across files and also removes the possibility of error in attribution when license blocks or files are copied across since the contributed-by lines don't actually reflect reality in those cases. Move all "Contributed by" and similar lines (Written by, Test by, etc.) into a new file CONTRIBUTED-BY to retain record of these contributions. These contributors are also mentioned in manual/contrib.texi, so we just maintain this additional record as a courtesy to the earlier developers. The following scripts were used to filter a list of files to edit in place and to clean up the CONTRIBUTED-BY file respectively. These were not added to the glibc sources because they're not expected to be of any use in future given that this is a one time task: https://gist.github.com/siddhesh/b5ecac94eabfd72ed2916d6d8157e7dc https://gist.github.com/siddhesh/15ea1f5e435ace9774f485030695ee02 Reviewed-by: Carlos O'Donell <carlos@redhat.com>
97 lines
2.7 KiB
ArmAsm
97 lines
2.7 KiB
ArmAsm
/* Optimized version of the standard strlen() function.
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This file is part of the GNU C Library.
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Copyright (C) 2000-2021 Free Software Foundation, Inc.
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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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/* Return: the length of the input string
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Input:
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in0: str
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Look for the null character byte by byte, until we reach a word aligned
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address, then search word by word, using the czx instruction. We're
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also doing one word of read ahead, which could cause problems if the
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null character is on the last word of a page and the next page is not
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mapped in the process address space. Hence the use of the speculative
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load.
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This implementation assumes little endian mode. For big endian mode,
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the instruction czx1.r should be replaced by czx1.l. */
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#include <sysdep.h>
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#undef ret
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#define saved_lc r18
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#define str r19
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#define pos0 r20
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#define val1 r21
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#define val2 r22
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#define origadd r23
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#define tmp r24
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#define loopcnt r30
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#define len ret0
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ENTRY(strlen)
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.prologue
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alloc r2 = ar.pfs, 1, 0, 0, 0
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.save ar.lc, saved_lc
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mov saved_lc = ar.lc // save the loop counter
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.body
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mov str = in0
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mov len = r0 // len = 0
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and tmp = 7, in0 // tmp = str % 8
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;;
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sub loopcnt = 8, tmp // loopcnt = 8 - tmp
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cmp.eq p6, p0 = tmp, r0
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(p6) br.cond.sptk .str_aligned;;
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adds loopcnt = -1, loopcnt;;
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mov ar.lc = loopcnt
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.l1:
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ld1 val2 = [str], 1
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;;
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cmp.eq p6, p0 = val2, r0
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(p6) br.cond.spnt .restore_and_exit
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adds len = 1, len
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br.cloop.dptk .l1
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.str_aligned:
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mov origadd = str // origadd = orig
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ld8 val1 = [str], 8;;
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nop.b 0
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nop.b 0
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.l2: ld8.s val2 = [str], 8 // don't bomb out here
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czx1.r pos0 = val1
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;;
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cmp.ne p6, p0 = 8, pos0
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(p6) br.cond.spnt .foundit
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chk.s val2, .recovery
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.back:
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mov val1 = val2
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br.cond.dptk .l2
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.foundit:
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sub tmp = str, origadd // tmp = crt address - orig
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add len = len, pos0;;
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add len = len, tmp;;
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adds len = -16, len
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.restore_and_exit:
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mov ar.lc = saved_lc // restore the loop counter
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br.ret.sptk.many b0
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.recovery:
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adds str = -8, str;;
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ld8 val2 = [str], 8 // bomb out here
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br.cond.sptk .back
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END(strlen)
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libc_hidden_builtin_def (strlen)
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