1/*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21/*
22 * Copyright 2004 Sun Microsystems, Inc.  All rights reserved.
23 * Use is subject to license terms.
24 */
25
26	.file	"_mul64.s"
27
28/
29/   function __mul64(A,B:Longint):Longint;
30/	{Overflow is not checked}
31/
32/ We essentially do multiply by longhand, using base 2**32 digits.
33/               a       b	parameter A
34/	     x 	c       d	parameter B
35/		---------
36/               ad      bd
37/       ac	bc
38/       -----------------
39/       ac	ad+bc	bd
40/
41/       We can ignore ac and top 32 bits of ad+bc: if <> 0, overflow happened.
42/
43
44#include "SYS.h"
45
46	ENTRY(__mul64)
47	push	%ebp
48	mov    	%esp,%ebp
49	pushl	%esi
50	mov	12(%ebp),%eax	/ A.hi (a)
51	mull	16(%ebp)	/ Multiply A.hi by B.lo (produces ad)
52	xchg	%ecx,%eax	/ ecx = bottom half of ad.
53	movl    8(%ebp),%eax	/ A.Lo (b)
54	movl	%eax,%esi	/ Save A.lo for later
55	mull	16(%ebp)	/ Multiply A.Lo by B.LO (dx:ax = bd.)
56	addl	%edx,%ecx	/ cx is ad
57	xchg	%eax,%esi       / esi is bd, eax = A.lo (d)
58	mull	20(%ebp)	/ Multiply A.lo * B.hi (producing bc)
59	addl	%ecx,%eax	/ Produce ad+bc
60	movl	%esi,%edx
61	xchg	%eax,%edx
62	popl	%esi
63	movl	%ebp,%esp
64	popl	%ebp
65	ret     $16
66	SET_SIZE(__mul64)
67