; $Id$

;; @file

; innotek Portable Runtime - No-CRT logl - AMD64 & X86.

;

;

; Copyright (C) 2006-2007 innotek GmbH

;

; This file is part of VirtualBox Open Source Edition (OSE), as

; available from http://www.virtualbox.org. This file is free software;

; you can redistribute it and/or modify it under the terms of the GNU

; General Public License as published by the Free Software Foundation,

; in version 2 as it comes in the "COPYING" file of the VirtualBox OSE

; distribution. VirtualBox OSE is distributed in the hope that it will

; be useful, but WITHOUT ANY WARRANTY of any kind.

%include "iprt/asmdefs.mac"

BEGINCODE

%ifdef RT_ARCH_AMD64

%define _SP rsp

%define _BP rbp

%define _S 8

%else

%define _SP esp

%define _BP ebp

%define _S 4

%endif

;;

; compute the natural logarithm of lrd

; @returns st(0)

; @param lrd [rbp + _S*2]

BEGINPROC RT_NOCRT(logl)

push _BP

mov _BP, _SP

sub _SP, 10h

fldln2 ; st0=log(2)

fld tword [_BP + _S*2] ; st1=log(2) st0=lrd

fld st0 ; st1=log(2) st0=lrd st0=lrd

fsub qword [.one] ; st2=log(2) st1=lrd st0=lrd-1.0

fld st0 ; st3=log(2) st2=lrd st1=lrd-1.0 st0=lrd-1.0

fabs ; st3=log(2) st2=lrd st1=lrd-1.0 st0=abs(lrd-1.0)

fcomp qword [.limit] ; st2=log(2) st1=lrd st0=lrd-1.0

fnstsw ax

and eax, 04500h

jnz .use_st1

fstp st0 ; st1=log(2) st0=lrd

fyl2x ; log(lrd)

jmp .done

.use_st1:

fstp st1 ; st1=log(2) st0=lrd-1.0

fyl2xp1 ; log(lrd)

.done:

leave

ret

.one: dq 1.0

.limit: dq 0.29

ENDPROC RT_NOCRT(logl)