| 1 | ; $Id: logl.asm 82968 2020-02-04 10:35:17Z vboxsync $
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| 2 | ;; @file
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| 3 | ; IPRT - No-CRT logl - AMD64 & X86.
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| 4 | ;
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| 5 |
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| 6 | ;
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| 7 | ; Copyright (C) 2006-2020 Oracle Corporation
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| 8 | ;
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| 9 | ; This file is part of VirtualBox Open Source Edition (OSE), as
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| 10 | ; available from http://www.virtualbox.org. This file is free software;
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| 11 | ; you can redistribute it and/or modify it under the terms of the GNU
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| 12 | ; General Public License (GPL) as published by the Free Software
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| 13 | ; Foundation, in version 2 as it comes in the "COPYING" file of the
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| 14 | ; VirtualBox OSE distribution. VirtualBox OSE is distributed in the
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| 15 | ; hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
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| 16 | ;
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| 17 | ; The contents of this file may alternatively be used under the terms
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| 18 | ; of the Common Development and Distribution License Version 1.0
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| 19 | ; (CDDL) only, as it comes in the "COPYING.CDDL" file of the
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| 20 | ; VirtualBox OSE distribution, in which case the provisions of the
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| 21 | ; CDDL are applicable instead of those of the GPL.
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| 22 | ;
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| 23 | ; You may elect to license modified versions of this file under the
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| 24 | ; terms and conditions of either the GPL or the CDDL or both.
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| 25 | ;
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| 26 |
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| 27 | %include "iprt/asmdefs.mac"
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| 28 |
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| 29 | BEGINCODE
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| 30 |
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| 31 | ;;
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| 32 | ; compute the natural logarithm of lrd
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| 33 | ; @returns st(0)
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| 34 | ; @param lrd [rbp + xCB*2]
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| 35 | BEGINPROC RT_NOCRT(logl)
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| 36 | push xBP
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| 37 | mov xBP, xSP
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| 38 | sub xSP, 10h
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| 39 |
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| 40 | fldln2 ; st0=log(2)
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| 41 | fld tword [xBP + xCB*2] ; st1=log(2) st0=lrd
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| 42 | fld st0 ; st1=log(2) st0=lrd st0=lrd
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| 43 | fsub qword [.one xWrtRIP] ; st2=log(2) st1=lrd st0=lrd-1.0
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| 44 | fld st0 ; st3=log(2) st2=lrd st1=lrd-1.0 st0=lrd-1.0
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| 45 | fabs ; st3=log(2) st2=lrd st1=lrd-1.0 st0=abs(lrd-1.0)
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| 46 | fcomp qword [.limit xWrtRIP] ; st2=log(2) st1=lrd st0=lrd-1.0
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| 47 | fnstsw ax
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| 48 | and eax, 04500h
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| 49 | jnz .use_st1
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| 50 |
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| 51 | fstp st0 ; st1=log(2) st0=lrd
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| 52 | fyl2x ; log(lrd)
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| 53 | jmp .done
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| 54 |
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| 55 | .use_st1:
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| 56 | fstp st1 ; st1=log(2) st0=lrd-1.0
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| 57 | fyl2xp1 ; log(lrd)
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| 58 |
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| 59 | .done:
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| 60 | leave
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| 61 | ret
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| 62 | .one: dq 1.0
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| 63 | .limit: dq 0.29
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| 64 | ENDPROC RT_NOCRT(logl)
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| 65 |
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