/* Optimized version of the standard strncpy() 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>

	      and Jakub Jelinek <jakub@redhat.com>.

   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: dest

   Inputs:

	in0:    dest

	in1:    src

	in2:	len

   In this form, it assumes little endian mode.

 */

#include <sysdep.h>

#undef ret

#define saved_lc	r15

#define saved_pr	r16

#define thresh		r17

#define dest		r18

#define dest2		r19

#define src		r20

#define len		r21

#define asrc		r22

#define tmp		r23

#define pos		r24

#define w0		r25

#define w1		r26

#define c		r27

#define sh2		r28

#define	sh1		r29

#define loopcnt		r30

#define	value		r31

ENTRY(strncpy)

	.prologue

	alloc 	r2 = ar.pfs, 3, 0, 29, 32

#define MEMLAT 2

	.rotr	r[MEMLAT + 2]

	.rotp	p[MEMLAT + 1]

	mov	ret0 = in0		// return value = dest

	.save pr, saved_pr

	mov	saved_pr = pr           // save the predicate registers

	.save ar.lc, saved_lc

	mov 	saved_lc = ar.lc	// save the loop counter

	mov	ar.ec = 0		// ec is not guaranteed to

					// be zero upon function entry

	.body

	cmp.geu p6, p5 = 24, in2

(p6)	br.cond.spnt .short_len

	sub	tmp = r0, in0 ;;	// tmp = -dest

	mov	len = in2		// len

	mov 	dest = in0		// dest

	mov 	src = in1		// src

	and	tmp = 7, tmp ;;		// loopcnt = -dest % 8

	cmp.eq	p6, p7 = tmp, r0

	adds	loopcnt = -1, tmp	// --loopcnt

(p6)	br.cond.sptk .dest_aligned ;;

	sub	len = len, tmp		// len -= -dest % 8

	mov	ar.lc = loopcnt

.l1:					// copy -dest % 8 bytes

(p5)	ld1	c = [src], 1		// c = *src++

	;;

	st1	[dest] = c, 1		// *dest++ = c

	cmp.ne	p5, p7 = c, r0

	br.cloop.dptk .l1 ;;

(p7)	br.cond.dpnt	.found0_align

.dest_aligned:				// p7 should be cleared here

	shr.u	c = len, 3		// c = len / 8

	and	sh1 = 7, src 		// sh1 = src % 8

	and	asrc = -8, src ;;	// asrc = src & -OPSIZ  -- align src

	adds	c = (MEMLAT-1), c	// c = (len / 8) + MEMLAT - 1

	sub	thresh = 8, sh1

	mov	pr.rot = 1 << 16	// set rotating predicates

	shl	sh1 = sh1, 3 ;;		// sh1 = 8 * (src % 8)

	mov	ar.lc = c		// "infinite" loop

	sub	sh2 = 64, sh1		// sh2 = 64 - sh1

	cmp.eq  p6, p0 = sh1, r0 	// is the src aligned?

(p6)    br.cond.sptk .src_aligned

	adds	c = -(MEMLAT-1), c ;;	// c = (len / 8)

	ld8	r[1] = [asrc],8

	mov	ar.lc = c ;;

	.align	32

.l2:

(p6)	st8	[dest] = value, 8	// store val to dest

	ld8.s	r[0] = [asrc], 8

	shr.u	value = r[1], sh1 ;; 	// value = w0 >> sh1

	czx1.r	pos = value ;;		// do we have an "early" zero

	cmp.lt	p7, p0 = pos, thresh	// in w0 >> sh1?

	adds	len = -8, len		// len -= 8

(p7)	br.cond.dpnt .nonalign_found0

	chk.s	r[0], .recovery2	// it is safe to do that only

.back2:					// after the previous test

	shl	tmp = r[0], sh2  	// tmp = w1 << sh2

	;;

	or	value = value, tmp ;;	// value |= tmp

	czx1.r	pos = value ;;

	cmp.ne	p7, p6 = 8, pos

(p7)	br.cond.dpnt .nonalign_found0

	br.ctop.dptk    .l2 ;;

	adds	len = 8, len

	br.cond.sptk	.not_found0 ;;

.nonalign_found0:

	cmp.gtu	p6, p0 = -8, len

(p6)	br.cond.dptk .found0

	adds	len = 8, len

	br.cond.sptk	.not_found0 ;;

	.align	32

.src_aligned:

.l3:

(p[0])		ld8.s	r[0] = [src], 8

(p[MEMLAT])	chk.s	r[MEMLAT], .recovery3

.back3:

(p[MEMLAT])	mov	value = r[MEMLAT]

(p[MEMLAT])	czx1.r	pos = r[MEMLAT] ;;

(p[MEMLAT])	cmp.ne	p7, p0 = 8, pos

(p[MEMLAT])	adds	len = -8, len	// len -= 8

(p7)		br.cond.dpnt .found0

(p[MEMLAT])	st8	[dest] = r[MEMLAT], 8

		br.ctop.dptk .l3 ;;

	chk.s	r[MEMLAT-1], .recovery4

.back4:

	mov	value = r[MEMLAT-1]

.not_found0:

	cmp.eq	p5, p6 = len, r0

	adds	len = -1, len

(p5)	br.cond.dptk	.restore_and_exit ;;

	mov	ar.lc = len

.l4:

(p6)	extr.u	c = value, 0, 8		// c = value & 0xff

(p6)	shr.u	value = value, 8 ;;

	st1	[dest] = c, 1

	cmp.ne	p6, p0 = c, r0

	br.cloop.dptk	.l4

	br.cond.sptk	.restore_and_exit

.found0_align:

	mov	pos = 0

	adds	len = -8, len

	mov	value = 0 ;;

.found0:

	shl	tmp = pos, 3

	shr.u	loopcnt = len, 4	// loopcnt = len / 16

	mov	c = -1 ;;

	cmp.eq	p6, p0 = loopcnt, r0

	adds	loopcnt = -1, loopcnt

	shl	c = c, tmp ;;

	and	len = 0xf, len

	andcm	value = value, c

	mov	ar.lc = loopcnt ;;

	cmp.le	p7, p0 = 8, len

	adds	dest2 = 16, dest

	st8	[dest] = value, 8

	and	len = 0x7, len

(p6)	br.cond.dpnt	.l6 ;;

.l5:

	st8	[dest] = r0, 16

	st8	[dest2] = r0, 16

	br.cloop.dptk	.l5 ;;

.l6:

(p7)	st8	[dest] = r0, 8

	cmp.eq	p5, p0 = len, r0

	adds	len = -1, len

(p5)	br.cond.dptk .restore_and_exit ;;

	mov	ar.lc = len ;;

.l7:

	st1	[dest] = r0, 1

	br.cloop.dptk	.l7 ;;

.restore_and_exit:

	mov 	ar.lc = saved_lc	// restore the loop counter

	mov	pr = saved_pr, -1	// restore the predicate registers

	br.ret.sptk.many b0

.short_len:

	cmp.eq	p5, p0 = in2, r0

	adds	loopcnt = -1, in2

(p5)	br.cond.spnt .restore_and_exit ;;

	mov	ar.lc = loopcnt		// p6 should be set when we get here

.l8:

(p6)	ld1	c = [in1], 1		// c = *src++

	;;

	st1	[in0] = c, 1		// *dest++ = c

(p6)	cmp.ne	p6, p0 = c, r0

	br.cloop.dptk .l8

	;;

	mov 	ar.lc = saved_lc	// restore the loop counter

	mov	pr = saved_pr, -1	// restore the predicate registers

	br.ret.sptk.many b0

.recovery2:

	add	c = 8, len

	add	tmp = -8, asrc ;;

	cmp.gtu	p8, p5 = c, thresh ;;

(p8)	ld8	r[0] = [tmp]

(p5)	mov	r[0] = r0

	br.cond.sptk .back2

.recovery3:

	add	tmp = -(MEMLAT + 1) * 8, src ;;

	ld8	r[MEMLAT] = [tmp]

	br.cond.sptk .back3

.recovery4:

	cmp.eq	p5, p6 = len, r0

	add	tmp = -MEMLAT * 8, src ;;

(p6)	ld8	r[MEMLAT - 1] = [tmp]

(p5)	mov	r[MEMLAT - 1] = r0

	br.cond.sptk .back4

END(strncpy)

libc_hidden_builtin_def (strncpy)