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/* Optimized version of the standard strncmp() function.
This file is part of the GNU C Library.
Copyright (C) 2000-2023 Free Software Foundation, Inc.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
/* Return: the result of the comparison
Inputs:
in0: s1
in1: s2
in2: n
Unlike memcmp(), this function is optimized for mismatches within the
first few characters. */
#include <sysdep.h>
#undef ret
#define s1 in0
#define s2 in1
#define n in2
#define val1 r15
#define val2 r16
ENTRY(strncmp)
alloc r2 = ar.pfs, 3, 0, 0, 0
mov ret0 = r0
cmp.eq p6, p0 = r0, r0 // set p6
cmp.eq p7, p0 = n, r0 // return immediately if n == 0
(p7) br.cond.spnt .restore_and_exit ;;
.loop:
ld1 val1 = [s1], 1
ld1 val2 = [s2], 1
adds n = -1, n // n--
;;
cmp.ne.and p6, p0 = val1, r0
cmp.ne.and p6, p0 = val2, r0
cmp.ne.and p6, p0 = n, r0
cmp.eq.and p6, p0 = val1, val2
(p6) br.cond.sptk .loop
sub ret0 = val1, val2
.restore_and_exit:
br.ret.sptk.many b0
END(strncmp)
libc_hidden_builtin_def (strncmp)
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