1/* $NetBSD: mulsi3.S,v 1.1 2014/09/03 19:34:25 matt Exp $ */
2
3/*-
4 * Copyright (c) 2014 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Matt Thomas of 3am Software Foundry.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 *    notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 *    notice, this list of conditions and the following disclaimer in the
17 *    documentation and/or other materials provided with the distribution.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
30 */
31
32#include <machine/asm.h>
33
34__RCSID("$NetBSD: mulsi3.S,v 1.1 2014/09/03 19:34:25 matt Exp $")
35
36ENTRY(__mulsi3)
37	l.movhi	r11, 0
38
39	l.sfeqi	r3, 0
40	l.bf	.Lret
41	l.nop
42
43	l.sfeqi	r4, 0
44	l.bf	.Lret
45	l.nop
46
47	l.sfleu	r3, r4		# is r3 < r4 (unsigned)
48#if 0
49	l.ori	r6, r3, 0	# move r3 to r6
50	l.bf	.Lloop		#   yes, r6 already has smaller value,
51	l.nop
52	l.ori	r6, r4, 0	# move r4 to r6 because it's smaller than r3
53#else
54	l.cmov	r6, r3, r4	# choose lesser of r3 or r4
55#endif
56
57.Lloop:
58	l.andi	r5, r6, 1	# get LSB
59	l.sub	r8, r0, r5	# 0 -> 0, 1 -> 0xffffffff
60	l.and	r8, r8, r4	# r8 = r6 & 1 ? r4 : 0
61	l.add	r11, r11, r8	# add to result
62	l.srli	r4, r4, 1	# discard LSB
63	l.slli	r6, r6, 1	# multiply by 2
64.Lentry:
65	l.sfeqi	r4, 0		# only 0 left?
66	l.bf	.Lret		#   yes, we're done
67	l.nop
68	l.sfeqi	r6, 0		# only 0 left?
69	l.bnf	.Lloop		#   no, another round of long multiplication.
70	l.nop
71
72.Lret:	l.jr	lr
73	l.nop
74END(__mulsi3)
75