glibc/sysdeps/arm/memset.S

/* Copyright (C) 1998 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by Philip Blundell <philb@gnu.org>

   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, write to the Free
   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
   02111-1307 USA.  */

#include <sysdep.h>

/* void *memset (dstpp, c, len) */

ENTRY(memset)
	mov	a4, a1
	cmp	a3, $8		@ at least 8 bytes to do?
	blt	2f
	orr	a2, a2, a2, lsl $8
	orr	a2, a2, a2, lsl $16
1:
	tst	a4, $3		@ aligned yet?
	strneb	a2, [a4], $1
	subne	a3, a3, $1
	bne	1b
	mov	ip, a2
1:
	cmp	a3, $8		@ 8 bytes still to do?
	blt	2f
	stmia	a4!, {a2, ip}
	sub	a3, a3, $8
	cmp	a3, $8		@ 8 bytes still to do?
	blt	2f
	stmia	a4!, {a2, ip}
	sub	a3, a3, $8
	cmp	a3, $8		@ 8 bytes still to do?
	blt	2f
	stmia	a4!, {a2, ip}
	sub	a3, a3, $8
	cmp	a3, $8		@ 8 bytes still to do?
	stmgeia	a4!, {a2, ip}
	subge	a3, a3, $8
	bge	1b
2:
	movs	a3, a3		@ anything left?
	RETINSTR(moveq,pc,lr)	@ nope
	rsb	a3, a3, $7
	add	pc, pc, a3, lsl $2
	mov	r0, r0
	strb	a2, [a4], $1
	strb	a2, [a4], $1
	strb	a2, [a4], $1
	strb	a2, [a4], $1
	strb	a2, [a4], $1
	strb	a2, [a4], $1
	strb	a2, [a4], $1
	RETINSTR(mov,pc,lr)
END(memset)