/* Optimized stpcpy implementation for PowerPC.

   Copyright (C) 1997-2018 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 <sysdep.h>

/* See strlen.s for comments on how the end-of-string testing works.  */

/* char * [r3] stpcpy (char *dest [r3], const char *src [r4])  */

EALIGN (__stpcpy, 4, 0)

#define rTMP	r0

#define rRTN	r3

#define rDEST	r3		/* pointer to previous word in dest */

#define rSRC	r4		/* pointer to previous word in src */

#define rWORD	r6		/* current word from src */

#define rFEFE	r7		/* 0xfefefeff */

#define r7F7F	r8		/* 0x7f7f7f7f */

#define rNEG	r9		/* ~(word in src | 0x7f7f7f7f) */

#define rALT	r10		/* alternate word from src */

	or	rTMP, rSRC, rDEST

	clrlwi.	rTMP, rTMP, 30

	addi	rDEST, rDEST, -4

	bne	L(unaligned)

	lis	rFEFE, -0x101

	lis	r7F7F, 0x7f7f

	lwz	rWORD, 0(rSRC)

	addi	rFEFE, rFEFE, -0x101

	addi	r7F7F, r7F7F, 0x7f7f

	b	L(g2)

L(g0):	lwzu	rALT, 4(rSRC)

	stwu	rWORD, 4(rDEST)

	add	rTMP, rFEFE, rALT

	nor	rNEG, r7F7F, rALT

	and.	rTMP, rTMP, rNEG

	bne-	L(g1)

	lwzu	rWORD, 4(rSRC)

	stwu	rALT, 4(rDEST)

L(g2):	add	rTMP, rFEFE, rWORD

	nor	rNEG, r7F7F, rWORD

	and.	rTMP, rTMP, rNEG

	beq+	L(g0)

	mr	rALT, rWORD

/* We've hit the end of the string.  Do the rest byte-by-byte.  */

L(g1):

#ifdef __LITTLE_ENDIAN__

	rlwinm.	rTMP, rALT, 0, 24, 31

	stbu	rALT, 4(rDEST)

	beqlr-

	rlwinm.	rTMP, rALT, 24, 24, 31

	stbu	rTMP, 1(rDEST)

	beqlr-

	rlwinm.	rTMP, rALT, 16, 24, 31

	stbu	rTMP, 1(rDEST)

	beqlr-

	rlwinm	rTMP, rALT, 8, 24, 31

	stbu	rTMP, 1(rDEST)

	blr

#else

	rlwinm.	rTMP, rALT, 8, 24, 31

	stbu	rTMP, 4(rDEST)

	beqlr-

	rlwinm.	rTMP, rALT, 16, 24, 31

	stbu	rTMP, 1(rDEST)

	beqlr-

	rlwinm.	rTMP, rALT, 24, 24, 31

	stbu	rTMP, 1(rDEST)

	beqlr-

	stbu	rALT, 1(rDEST)

	blr

#endif

/* Oh well.  In this case, we just do a byte-by-byte copy.  */

	.align 4

	nop

L(unaligned):

	lbz	rWORD, 0(rSRC)

	addi	rDEST, rDEST, 3

	cmpwi	rWORD, 0

	beq-	L(u2)

L(u0):	lbzu	rALT, 1(rSRC)

	stbu	rWORD, 1(rDEST)

	cmpwi	rALT, 0

	beq-	L(u1)

	nop		/* Let 601 load start of loop.  */

	lbzu	rWORD, 1(rSRC)

	stbu	rALT, 1(rDEST)

	cmpwi	rWORD, 0

	bne+	L(u0)

L(u2):	stbu	rWORD, 1(rDEST)

	blr

L(u1):	stbu	rALT, 1(rDEST)

	blr

END (__stpcpy)

weak_alias (__stpcpy, stpcpy)

libc_hidden_def (__stpcpy)

libc_hidden_builtin_def (stpcpy)