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61 lines
1.7 KiB
ArmAsm
61 lines
1.7 KiB
ArmAsm
/* Optimized version of the standard strncmp() function.
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This file is part of the GNU C Library.
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Copyright (C) 2000-2024 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 result of the comparison
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Inputs:
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in0: s1
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in1: s2
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in2: n
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Unlike memcmp(), this function is optimized for mismatches within the
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first few characters. */
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#include <sysdep.h>
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#undef ret
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#define s1 in0
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#define s2 in1
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#define n in2
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#define val1 r15
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#define val2 r16
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ENTRY(strncmp)
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alloc r2 = ar.pfs, 3, 0, 0, 0
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mov ret0 = r0
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cmp.eq p6, p0 = r0, r0 // set p6
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cmp.eq p7, p0 = n, r0 // return immediately if n == 0
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(p7) br.cond.spnt .restore_and_exit ;;
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.loop:
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ld1 val1 = [s1], 1
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ld1 val2 = [s2], 1
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adds n = -1, n // n--
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;;
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cmp.ne.and p6, p0 = val1, r0
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cmp.ne.and p6, p0 = val2, r0
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cmp.ne.and p6, p0 = n, r0
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cmp.eq.and p6, p0 = val1, val2
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(p6) br.cond.sptk .loop
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sub ret0 = val1, val2
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.restore_and_exit:
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br.ret.sptk.many b0
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END(strncmp)
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libc_hidden_builtin_def (strncmp)
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