; $Id$

;; @file

; IPRT - No-CRT logl - AMD64 & X86.

;

;

; Copyright (C) 2006-2007 Oracle Corporation

;

; 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 (GPL) 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.

;

; The contents of this file may alternatively be used under the terms

; of the Common Development and Distribution License Version 1.0

; (CDDL) only, as it comes in the "COPYING.CDDL" file of the

; VirtualBox OSE distribution, in which case the provisions of the

; CDDL are applicable instead of those of the GPL.

;

; You may elect to license modified versions of this file under the

; terms and conditions of either the GPL or the CDDL or both.

;

%include "iprt/asmdefs.mac"

BEGINCODE

;;

; compute the natural logarithm of lrd

; @returns st(0)

; @param lrd [rbp + xS*2]

BEGINPROC RT_NOCRT(logl)

push xBP

mov xBP, xSP

sub xSP, 10h

fldln2 ; st0=log(2)

fld tword [xBP + xS*2] ; st1=log(2) st0=lrd

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

fsub qword [.one xWrtRIP] ; 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 xWrtRIP] ; 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)