/* Copyright (C) 1998-2018 Free Software Foundation, Inc.

   This file is part of the GNU C Library.

   Code contributed by Matthew Wilcox <willy@odie.barnet.ac.uk>

   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/>.  */

/* Thumb requires excessive IT insns here.  */

#define NO_THUMB

#include <sysdep.h>

/* size_t strlen(const char *S)

 * entry: r0 -> string

 * exit: r0 = len

 */

	.syntax unified

	.text

ENTRY(strlen)

	bic     r1, r0, $3              @ addr of word containing first byte

	ldr     r2, [r1], $4            @ get the first word

	ands    r3, r0, $3              @ how many bytes are duff?

	rsb     r0, r3, $0              @ get - that number into counter.

	beq     Laligned                @ skip into main check routine if no

					@ more

#ifdef __ARMEB__

	orr     r2, r2, $0xff000000     @ set this byte to non-zero

	subs    r3, r3, $1              @ any more to do?

	orrgt   r2, r2, $0x00ff0000     @ if so, set this byte

	subs    r3, r3, $1              @ more?

	orrgt   r2, r2, $0x0000ff00     @ then set.

#else

	orr     r2, r2, $0x000000ff     @ set this byte to non-zero

	subs    r3, r3, $1              @ any more to do?

	orrgt   r2, r2, $0x0000ff00     @ if so, set this byte

	subs    r3, r3, $1              @ more?

	orrgt   r2, r2, $0x00ff0000     @ then set.

#endif

Laligned:				@ here, we have a word in r2.  Does it

	tst     r2, $0x000000ff         @ contain any zeroes?

	tstne   r2, $0x0000ff00         @

	tstne   r2, $0x00ff0000         @

	tstne   r2, $0xff000000         @

	addne   r0, r0, $4              @ if not, the string is 4 bytes longer

	ldrne   r2, [r1], $4            @ and we continue to the next word

	bne     Laligned                @

Llastword:				@ drop through to here once we find a

#ifdef __ARMEB__

	tst     r2, $0xff000000         @ word that has a zero byte in it

	addne   r0, r0, $1              @

	tstne   r2, $0x00ff0000         @ and add up to 3 bytes on to it

	addne   r0, r0, $1              @

	tstne   r2, $0x0000ff00         @ (if first three all non-zero, 4th

	addne   r0, r0, $1              @  must be zero)

#else

	tst     r2, $0x000000ff         @ word that has a zero byte in it

	addne   r0, r0, $1              @

	tstne   r2, $0x0000ff00         @ and add up to 3 bytes on to it

	addne   r0, r0, $1              @

	tstne   r2, $0x00ff0000         @ (if first three all non-zero, 4th

	addne   r0, r0, $1              @  must be zero)

#endif

	DO_RET(lr)

END(strlen)

libc_hidden_builtin_def (strlen)