/* Copyright (C) 1996-2018 Free Software Foundation, Inc.

   Contributed by David Mosberger (davidm@cs.arizona.edu).

   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/>.  */

/* Finds the first bit set in an integer.  Optimized for the Alpha

   architecture.  */

#include <sysdep.h>

	.set noreorder

	.set noat

ENTRY(__ffs)

#ifdef PROF

	ldgp	gp, 0(pv)

	lda	AT, _mcount

	jsr	AT, (AT), _mcount

	.prologue 1

	zap	$16, 0xF0, $16

	br	$ffsl..ng

#else

	.prologue 0

	zap	$16, 0xF0, $16

	# FALLTHRU

#endif

END(__ffs)

	.align 4

ENTRY(ffsl)

#ifdef PROF

	ldgp	gp, 0(pv)

	lda	AT, _mcount

	jsr	AT, (AT), _mcount

	.prologue 1

$ffsl..ng:

#else

	.prologue 0

#endif

	not	$16, $1		# e0    :

	ldi	$2, -1		# .. e1 :

	cmpbge	$1, $2, $3	# e0    : bit N == 1 for byte N == 0

	clr	$0		# .. e1 :

	addq	$3, 1, $4	# e0    :

	bic	$4, $3, $3	# e1    : bit N == 1 for first byte N != 0

	and	$3, 0xF0, $4	# e0    :

	and	$3, 0xCC, $5	# .. e1 :

	and	$3, 0xAA, $6	# e0    :

	cmovne	$4, 4, $0	# .. e1 :

	cmovne	$5, 2, $5	# e0    :

	cmovne  $6, 1, $6	# .. e1 :

	addl	$0, $5, $0	# e0    :

	addl	$0, $6, $0	# e1    : $0 == N

	extbl	$16, $0, $1	# e0    : $1 == byte N

	ldi	$2, 1		# .. e1 :

	negq	$1, $3		# e0    :

	and	$3, $1, $3	# e1    : bit N == least bit set of byte N

	and	$3, 0xF0, $4	# e0    :

	and	$3, 0xCC, $5	# .. e1 :

	and	$3, 0xAA, $6	# e0    :

	cmovne	$4, 5, $2	# .. e1 :

	cmovne	$5, 2, $5	# e0    :

	cmovne	$6, 1, $6	# .. e1 :

	s8addl	$0, $2, $0	# e0    : mult byte ofs by 8 and sum

	addl	$5, $6, $5	# .. e1 :

	addl	$0, $5, $0	# e0    :

	nop			# .. e1 :

	cmoveq	$16, 0, $0	# e0    : trap input == 0 case.

	ret			# .. e1 : 18

END(ffsl)

weak_alias (__ffs, ffs)

libc_hidden_def (__ffs)

libc_hidden_builtin_def (ffs)

weak_extern (ffsl)

weak_alias (ffsl, ffsll)