VirtualBox

source: vbox/trunk/src/VBox/Runtime/common/math/log.asm@ 96206

Last change on this file since 96206 was 96060, checked in by vboxsync, 2 years ago

IPRT/nocrt: Make use of existing floating point assembly code, morphing it into double and float variants where those were missing. bugref:10261

  • Property svn:eol-style set to native
  • Property svn:keywords set to Author Date Id Revision
File size: 2.3 KB
Line 
1; $Id: log.asm 96060 2022-08-05 12:22:06Z vboxsync $
2;; @file
3; IPRT - No-CRT log - AMD64 & X86.
4;
5
6;
7; Copyright (C) 2006-2022 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 natural logarithm of rd
33; @returns st(0) / xmm0
34; @param rd [rbp + xCB*2] / xmm0
35RT_NOCRT_BEGINPROC log
36 push xBP
37 mov xBP, xSP
38%ifdef RT_ARCH_AMD64
39 sub xSP, 10h
40%endif
41
42 fldln2 ; st0=log(2)
43%ifdef RT_ARCH_AMD64
44 movsd [xSP], xmm0
45 fld qword [xSP]
46%else
47 fld qword [xBP + xCB*2] ; st1=log(2) st0=lrd
48%endif
49 fld st0 ; st1=log(2) st0=lrd st0=lrd
50 fsub qword [.one xWrtRIP] ; st2=log(2) st1=lrd st0=lrd-1.0
51 fld st0 ; st3=log(2) st2=lrd st1=lrd-1.0 st0=lrd-1.0
52 fabs ; st3=log(2) st2=lrd st1=lrd-1.0 st0=abs(lrd-1.0)
53 fcomp qword [.limit xWrtRIP] ; st2=log(2) st1=lrd st0=lrd-1.0
54 fnstsw ax
55 and eax, 04500h
56 jnz .use_st1
57
58 fstp st0 ; st1=log(2) st0=lrd
59 fyl2x ; log(lrd)
60 jmp .done
61
62.use_st1:
63 fstp st1 ; st1=log(2) st0=lrd-1.0
64 fyl2xp1 ; log(lrd)
65
66.done:
67%ifdef RT_ARCH_AMD64
68 fstp qword [xSP]
69 movsd xmm0, [xSP]
70%endif
71 leave
72 ret
73.one: dq 1.0
74.limit: dq 0.29
75ENDPROC RT_NOCRT(log)
76
Note: See TracBrowser for help on using the repository browser.

© 2024 Oracle Support Privacy / Do Not Sell My Info Terms of Use Trademark Policy Automated Access Etiquette