VirtualBox

source: vbox/trunk/src/VBox/Runtime/math/floor.asm@ 4725

Last change on this file since 4725 was 4071, checked in by vboxsync, 17 years ago

Biggest check-in ever. New source code headers for all (C) innotek files.

  • Property svn:keywords set to Id
File size: 1.6 KB
Line 
1; $Id: floor.asm 4071 2007-08-07 17:07:59Z vboxsync $
2;; @file
3; innotek Portable Runtime - No-CRT floor - AMD64 & X86.
4;
5
6;
7; Copyright (C) 2006-2007 innotek GmbH
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 as published by the Free Software Foundation,
13; in version 2 as it comes in the "COPYING" file of the VirtualBox OSE
14; distribution. VirtualBox OSE is distributed in the hope that it will
15; be useful, but WITHOUT ANY WARRANTY of any kind.
16
17%include "iprt/asmdefs.mac"
18
19BEGINCODE
20
21%ifdef RT_ARCH_AMD64
22 %define _SP rsp
23 %define _BP rbp
24 %define _S 8
25%else
26 %define _SP esp
27 %define _BP ebp
28 %define _S 4
29%endif
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 _BP
37 mov _BP, _SP
38 sub _SP, 10h
39
40%ifdef RT_ARCH_AMD64
41 movsd [_SP], xmm0
42 fld qword [_SP]
43%else
44 fld qword [_BP + _S*2]
45%endif
46
47 ; Make it round down by modifying the fpu control word.
48 fstcw [_BP - 10h]
49 mov eax, [_BP - 10h]
50 or eax, 00400h
51 and eax, 0f7ffh
52 mov [_BP - 08h], eax
53 fldcw [_BP - 08h]
54
55 ; Round ST(0) to integer.
56 frndint
57
58 ; Restore the fpu control word.
59 fldcw [_BP - 10h]
60
61%ifdef RT_ARCH_AMD64
62 fstp qword [_SP]
63 movsd xmm0, [_SP]
64%endif
65 leave
66 ret
67ENDPROC RT_NOCRT(floor)
68
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