VirtualBox

source: vbox/trunk/src/VBox/Runtime/math/truncf.asm@ 4642

Last change on this file since 4642 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: 1.5 KB
Line 
1; $Id: truncf.asm 4071 2007-08-07 17:07:59Z vboxsync $
2;; @file
3; innotek Portable Runtime - No-CRT truncf - 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
18%include "iprt/asmdefs.mac"
19
20BEGINCODE
21
22%ifdef RT_ARCH_AMD64
23 %define _SP rsp
24 %define _BP rbp
25 %define _S 8
26%else
27 %define _SP esp
28 %define _BP ebp
29 %define _S 4
30%endif
31
32;;
33; Round to truncated integer value.
34; @returns 32-bit: st(0) 64-bit: xmm0
35; @param rf 32-bit: [ebp + 8] 64-bit: xmm0
36BEGINPROC RT_NOCRT(truncf)
37 push _BP
38 mov _BP, _SP
39 sub _SP, 10h
40
41%ifdef RT_ARCH_AMD64
42 movss [_SP], xmm0
43 fld dword [_SP]
44%else
45 fld dword [_BP + _S*2]
46%endif
47
48 ; Make it truncate up by modifying the fpu control word.
49 fstcw [_BP - 10h]
50 mov eax, [_BP - 10h]
51 or eax, 00c00h
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 dword [_SP]
63 movss xmm0, [_SP]
64%endif
65 leave
66 ret
67ENDPROC RT_NOCRT(truncf)
68
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