/* Optimized version of the standard strcpy() 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: dest

   Inputs:

        in0:    dest

        in1:    src

   In this form, it assumes little endian mode.  For big endian mode,

   the two shifts in .l2 must be inverted:

	shl   	value = r[1], sh1   	// value = w0 << sh1

	shr.u   tmp = r[0], sh2   	// tmp = w1 >> sh2

 */

#include <sysdep.h>

#undef ret

#define saved_lc	r15

#define saved_pr	r16

#define thresh		r17

#define dest		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(strcpy)

	.prologue

	alloc 	r2 = ar.pfs, 2, 0, 30, 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

	.body

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

	mov 	dest = in0		// dest

	mov 	src = in1		// src

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

	cmp.eq	p6, p0 = loopcnt, r0

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

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

	mov	ar.lc = loopcnt

.l1:					// copy -dest % 8 bytes

	ld1	c = [src], 1		// c = *src++

	;;

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

	cmp.eq	p6, p0 = c, r0

(p6)	br.cond.dpnt .restore_and_exit

	br.cloop.dptk .l1 ;;

.dest_aligned:

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

	mov	ar.lc = -1		// "infinite" loop

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

	sub	thresh = 8, sh1

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

	cmp.ne	p7, p0 = r0, r0		// clear p7

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

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

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

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

	ld8	r[1] = [asrc],8 ;;

	.align	32

.l2:

	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?

(p7)	br.cond.dpnt .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, p0 = 8, pos

(p7)	br.cond.dpnt .found0

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

	br.ctop.dptk    .l2 ;;

.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

(p7)		br.cond.dpnt .found0

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

		br.ctop.dptk .l3 ;;

.found0:

	mov	ar.lc = pos

.l4:

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

	shr.u	value = value, 8

	;;

	st1	[dest] = c, 1

	br.cloop.dptk	.l4 ;;

.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

.recovery2:

	add	tmp = -8, asrc ;;

	ld8	r[0] = [tmp]

	br.cond.sptk .back2

.recovery3:

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

	ld8	r[MEMLAT] = [tmp]

	br.cond.sptk .back3

END(strcpy)

libc_hidden_builtin_def (strcpy)