/* Optimized version of the standard strncmp() function.

   This file is part of the GNU C Library.

   Copyright (C) 2000-2018 Free Software Foundation, Inc.

   Contributed by Dan Pop <Dan.Pop@cern.ch>.

   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

   <http://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)