1 files changed, 90 insertions, 0 deletions
diff --git a/ports/sysdeps/alpha/ffs.S b/ports/sysdeps/alpha/ffs.S
new file mode 100644
index 0000000000..525bf66f2c
--- /dev/null
+++ b/ports/sysdeps/alpha/ffs.S
@@ -0,0 +1,90 @@
+/* Copyright (C) 1996, 1997, 1998, 2004 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_builtin_def (ffs)
+weak_extern (ffsl)
+weak_alias (ffsl, ffsll)