VirtualBox

source: vbox/trunk/src/VBox/Runtime/common/math/floor.asm@ 81106

Last change on this file since 81106 was 76553, checked in by vboxsync, 6 years ago

scm --update-copyright-year

  • Property svn:eol-style set to native
  • Property svn:keywords set to Author Date Id Revision
File size: 1.8 KB
Line 
1; $Id: floor.asm 76553 2019-01-01 01:45:53Z vboxsync $
2;; @file
3; IPRT - No-CRT floor - AMD64 & X86.
4;
5
6;
7; Copyright (C) 2006-2019 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; The contents of this file may alternatively be used under the terms
18; of the Common Development and Distribution License Version 1.0
19; (CDDL) only, as it comes in the "COPYING.CDDL" file of the
20; VirtualBox OSE distribution, in which case the provisions of the
21; CDDL are applicable instead of those of the GPL.
22;
23; You may elect to license modified versions of this file under the
24; terms and conditions of either the GPL or the CDDL or both.
25;
26
27%include "iprt/asmdefs.mac"
28
29BEGINCODE
30
31;;
32; Compute the largest integral value not greater than rd.
33; @returns 32-bit: st(0) 64-bit: xmm0
34; @param rd 32-bit: [ebp + 8] 64-bit: xmm0
35BEGINPROC RT_NOCRT(floor)
36 push xBP
37 mov xBP, xSP
38 sub xSP, 10h
39
40%ifdef RT_ARCH_AMD64
41 movsd [xSP], xmm0
42 fld qword [xSP]
43%else
44 fld qword [xBP + xCB*2]
45%endif
46
47 ; Make it round down by modifying the fpu control word.
48 fstcw [xBP - 10h]
49 mov eax, [xBP - 10h]
50 or eax, 00400h
51 and eax, 0f7ffh
52 mov [xBP - 08h], eax
53 fldcw [xBP - 08h]
54
55 ; Round ST(0) to integer.
56 frndint
57
58 ; Restore the fpu control word.
59 fldcw [xBP - 10h]
60
61%ifdef RT_ARCH_AMD64
62 fstp qword [xSP]
63 movsd xmm0, [xSP]
64%endif
65 leave
66 ret
67ENDPROC RT_NOCRT(floor)
68
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