/* Vector optimized 32/64 bit S/390 version of wcsncmp.

   Copyright (C) 2015-2018 Free Software Foundation, Inc.

   This file is part of the GNU C Library.

   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/>.  */

#include <ifunc-wcsncmp.h>

#if HAVE_WCSNCMP_Z13

# include "sysdep.h"

# include "asm-syntax.h"

	.text

/* int wcsncmp (const wchar_t *s1, const wchar_t *s2, size_t n)

   Compare at most n characters of two strings.

   Register usage:

   -r0=tmp

   -r1=tmp

   -r2=s1

   -r3=s2

   -r4=n

   -r5=current_len

   -v16=part of s1

   -v17=part of s2

   -v18=index of unequal

*/

ENTRY(WCSNCMP_Z13)

	.machine "z13"

	.machinemode "zarch_nohighgprs"

# if !defined __s390x__

	llgfr	%r4,%r4

# endif /* !defined __s390x__ */

	clgije	%r4,0,.Lend_equal /* Nothing to do if n == 0.  */

	/* Check range of n and convert to byte-count.  */

# ifdef __s390x__

	tmhh	%r4,49152	/* Test bit 0 or 1 of maxlen.  */

	lghi	%r1,-4		/* Max byte-count is 18446744073709551612.  */

# else

	tmlh	%r4,49152	/* Test bit 0 or 1 of maxlen.  */

	llilf	%r1,4294967292	/* Max byte-count is 4294967292.  */

# endif /* !__s390x__ */

	sllg	%r4,%r4,2	/* Convert character-count to byte-count.  */

	locgrne	%r4,%r1		/* Use max byte-count, if bit 0/1 was one.  */

	/* Check first character without vector load.  */

	lghi	%r5,4		/* current_len = 4 bytes.  */

	/* Check s1/2[0].  */

	lt	%r0,0(%r2)

	l	%r1,0(%r3)

	je	.Lend_cmp_one_char

	crjne	%r0,%r1,.Lend_cmp_one_char

.Lloop:

	vlbb	%v17,0(%r5,%r3),6 /* Load s2 to block boundary.  */

	vlbb	%v16,0(%r5,%r2),6 /* Load s1 to block boundary.  */

	lcbb	%r0,0(%r5,%r2),6 /* Get loaded byte count of s1.  */

	jo	.Llt16_1	/* Jump away if vector not fully loaded.  */

	lcbb	%r1,0(%r5,%r3),6 /* Get loaded byte count of s2.  */

	jo	.Llt16_2	/* Jump away if vector not fully loaded.  */

	aghi	%r5,16		/* Both vectors are fully loaded.  */

	vfenezfs %v18,%v16,%v17	/* Compare not equal with zero search.  */

	clgrjhe	%r5,%r4,.Llastcmp /* If current_len >= n ->last compare.  */

	jno	.Lfound

	vlbb	%v17,0(%r5,%r3),6

	vlbb	%v16,0(%r5,%r2),6

	lcbb	%r0,0(%r5,%r2),6

	jo	.Llt16_1

	lcbb	%r1,0(%r5,%r3),6

	jo	.Llt16_2

	aghi	%r5,16

	vfenezfs %v18,%v16,%v17

	clgrjhe	%r5,%r4,.Llastcmp

	jno	.Lfound

	vlbb	%v17,0(%r5,%r3),6

	vlbb	%v16,0(%r5,%r2),6

	lcbb	%r0,0(%r5,%r2),6

	jo	.Llt16_1

	lcbb	%r1,0(%r5,%r3),6

	jo	.Llt16_2

	aghi	%r5,16

	vfenezfs %v18,%v16,%v17

	clgrjhe	%r5,%r4,.Llastcmp

	jno	.Lfound

	vlbb	%v17,0(%r5,%r3),6

	vlbb	%v16,0(%r5,%r2),6

	lcbb	%r0,0(%r5,%r2),6

	jo	.Llt16_1

	lcbb	%r1,0(%r5,%r3),6

	jo	.Llt16_2

	aghi	%r5,16

	vfenezfs %v18,%v16,%v17

	clgrjhe	%r5,%r4,.Llastcmp

	jno	.Lfound

	j	.Lloop

.Llt16_1:

	lcbb	%r1,0(%r5,%r3),6 /* Get loaded byte count of s2.  */

.Llt16_2:

	clr	%r0,%r1		/* Compare logical.  */

	locrh	%r0,%r1		/* Compute minimum of bytes loaded.  */

	nill	%r0,65532	/* Align bytes loaded to full characters.  */

	jz	.Lcmp_one_char	/* Jump away if no full char is available.  */

.Llt_cmp:

	algfr	%r5,%r0		/* Add smallest loaded bytes to current_len.  */

	vfenezfs %v18,%v16,%v17	/* Compare not equal with zero search.  */

	clgrj	%r5,%r4,10,.Llastcmp /* If current_len >= n -> last compare  */

	vlgvb	%r1,%v18,7	/* Get not equal index or 16 if all equal.  */

	clrjl	%r1,%r0,.Lfound /* Jump away if miscompare is within

				   loaded bytes; (index < loaded-bytes) */

	j	.Lloop

.Lcmp_one_char:

	/* At least one of both strings is not 4-byte aligned

	   and there is no full character before next block-boundary.

	   Compare one character to get over the boundary and

	   proceed with normal loop!  */

	vlef	%v16,0(%r5,%r2),0 /* Load one character.  */

	lghi	%r0,4		/* Loaded byte count is 4.  */

	vlef	%v17,0(%r5,%r3),0

	j	.Llt_cmp	/* Proceed with comparision.  */

.Llastcmp:

	/* Use comparision result only if located within first n characters.

	   %r0: loaded byte count in vreg;

	   %r5: current_len;

	   %r4: n;

	   (current_len - n): [0...16[

	   First ignored match index: loaded bytes - (current_len-n): ]0...16]

	*/

	slgr	%r5,%r4		/* %r5 = current_len - n.  */

	slr	%r0,%r5		/* %r0 = first ignored match index.  */

	vlgvb	%r4,%v18,7	/* Get not equal index or 16 if all equal.  */

	clrjl	%r4,%r0,.Lfound2 /* Jump away if miscompare is within

				     loaded bytes and below n bytes.  */

.Lend_equal:

	lghi	%r2,0

	br	%r14

.Lfound:

	/* Difference or end of string.  */

	/* vfenezf found an unequal element or zero.

	   This instruction compares unsigned words, but wchar_t is signed.

	   Thus we have to compare the found element again.  */

	vlgvb	%r4,%v18,7	/* Extract not equal byte-index.  */

.Lfound2:

	srl	%r4,2		/* And convert it to character-index.  */

	vlgvf	%r0,%v16,0(%r4)	/* Load character-values.  */

	vlgvf	%r1,%v17,0(%r4)

.Lend_cmp_one_char:

	cr	%r0,%r1

	je	.Lend_equal

	lghi	%r2,1

	lghi	%r1,-1

	locgrl	%r2,%r1

	br	%r14

END(WCSNCMP_Z13)

# if ! HAVE_WCSNCMP_IFUNC

strong_alias (WCSNCMP_Z13, wcsncmp)

# endif

#endif