VirtualBox

source: vbox/trunk/src/VBox/Devices/BiosCommonCode/__I4M.asm@ 68080

Last change on this file since 68080 was 62518, checked in by vboxsync, 8 years ago

(C) 2016

  • Property svn:eol-style set to native
  • Property svn:keywords set to Author Date Id Revision
File size: 2.0 KB
Line 
1; $Id: __I4M.asm 62518 2016-07-22 19:14:29Z vboxsync $
2;; @file
3; Compiler support routines.
4;
5
6;
7; Copyright (C) 2012-2016 Oracle Corporation
8;
9; This file is part of VirtualBox Open Source Edition (OSE), as
10; available from http://www.virtualbox.org. This file is free software;
11; you can redistribute it and/or modify it under the terms of the GNU
12; General Public License (GPL) as published by the Free Software
13; Foundation, in version 2 as it comes in the "COPYING" file of the
14; VirtualBox OSE distribution. VirtualBox OSE is distributed in the
15; hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
16;
17
18
19;*******************************************************************************
20;* Exported Symbols *
21;*******************************************************************************
22public __I4M
23
24if VBOX_BIOS_CPU lt 80386
25extrn NeedToImplementOn8086__I4M:near
26endif
27
28 .8086
29
30_TEXT segment public 'CODE' use16
31 assume cs:_TEXT
32
33;;
34; 32-bit signed multiplication.
35;
36; @param dx:ax Factor 1.
37; @param cx:bx Factor 2.
38; @returns dx:ax Result.
39; cx, es may be modified; di is preserved
40;
41__I4M:
42 pushf
43if VBOX_BIOS_CPU ge 80386
44 .386
45 push eax
46 push edx
47 push ecx
48 push ebx
49
50 rol eax, 16
51 mov ax, dx
52 ror eax, 16
53 xor edx, edx
54
55 shr ecx, 16
56 mov cx, bx
57
58 imul ecx ; eax * ecx -> edx:eax
59
60 pop ebx
61 pop ecx
62
63 pop edx
64 ror eax, 16
65 mov dx, ax
66 add sp, 2
67 pop ax
68 rol eax, 16
69 .8086
70else
71 call NeedToImplementOn8086__I4M
72endif
73
74 popf
75 ret
76
77
78_TEXT ends
79 end
80
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