148 lines
3.9 KiB
C
148 lines
3.9 KiB
C
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/***
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*fenv.h - definitions and declarations for floating point environment library
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*
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* Copyright (c) Microsoft Corporation. All rights reserved.
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*
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*Purpose:
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* This file contains constant definitions and external subroutine
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* declarations for the floating point environment subroutine library.
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*
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* [Public]
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*
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****/
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#pragma once
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#ifndef _FENV
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#define _FENV
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#include <float.h>
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/*
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* Currently, all MS C compilers for Win32 platforms default to 8 byte
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* alignment.
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*/
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#pragma pack(push,_CRT_PACKING)
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#ifdef __cplusplus
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extern "C" {
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#endif /* __cplusplus */
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#if !defined(_M_CEE) || defined(_CRTBLD)
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typedef unsigned long fexcept_t;
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typedef struct fenv_t
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{
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unsigned long _Fe_ctl, _Fe_stat;
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} fenv_t;
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#define FE_INEXACT _SW_INEXACT /* _EM_INEXACT 0x00000001 inexact (precision) */
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#define FE_UNDERFLOW _SW_UNDERFLOW /* _EM_UNDERFLOW 0x00000002 underflow */
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#define FE_OVERFLOW _SW_OVERFLOW /* _EM_OVERFLOW 0x00000004 overflow */
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#define FE_DIVBYZERO _SW_ZERODIVIDE /* _EM_ZERODIVIDE 0x00000008 zero divide */
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#define FE_INVALID _SW_INVALID /* _EM_INVALID 0x00000010 invalid */
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#define FE_ALL_EXCEPT (FE_DIVBYZERO | FE_INEXACT | FE_INVALID | FE_OVERFLOW | FE_UNDERFLOW)
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_CRTIMP int __cdecl fegetenv(_Inout_ fenv_t *);
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_CRTIMP int __cdecl fesetenv(_In_ const fenv_t *);
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_CRTIMP int __cdecl feclearexcept(_In_ int);
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_CRTIMP int __cdecl feholdexcept(_Inout_ fenv_t *);
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_CRTIMP int __cdecl fetestexcept(_In_ int);
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_CRTIMP int __cdecl fegetexceptflag(_Inout_ fexcept_t *, _In_ int);
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_CRTIMP int __cdecl fesetexceptflag(_In_ const fexcept_t *, _In_ int);
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__declspec(selectany) extern const fenv_t _Fenv0 = {0, 0};
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#define FE_DFL_ENV (&_Fenv0)
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#endif /* !defined(_M_CEE) || defined(_CRTBLD) */
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#define FE_TONEAREST 0x0000
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#define FE_UPWARD 0x0100
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#define FE_DOWNWARD 0x0200
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#define FE_TOWARDZERO 0x0300
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#define FE_ROUND_MASK 0x0300
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_CRTIMP int __cdecl fegetround(void);
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_CRTIMP int __cdecl fesetround(_In_ int);
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#if !defined(_M_CEE) && !defined(_CRTBLD)
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/*
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* feraiseexcept is inline in this header so that it will be compiled with
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* the /arch setting specified in the consuming application, rather than the
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* /arch:IA32 setting which is the default for the CRT library itself.
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*
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* feupdateenv is inline because it calls feraiseexcept.
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*/
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__inline int __CRTDECL feraiseexcept(_In_ int _Except)
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{
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#define __DBL_BIG 1e+300 /* may raise inexact too */
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static struct
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{
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int _Except_Val;
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double _Num, _Denom;
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} const _Table[] =
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{ /* raise exception by evaluating num / denom */
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{FE_INVALID, 0.0, 0.0},
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{FE_DIVBYZERO, 1.0, 0.0},
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{FE_OVERFLOW, __DBL_BIG, 1.0 / __DBL_BIG},
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{FE_UNDERFLOW, 1.0 / __DBL_BIG, __DBL_BIG},
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{FE_INEXACT, 2.0, 3.0}
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};
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fexcept_t _Flags = 0;
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double _Ans = 0.0;
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int _N;
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if ((_Except &= FE_ALL_EXCEPT) == 0)
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{
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return 0;
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}
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/* get the current status flags */
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fegetexceptflag(&_Flags, FE_ALL_EXCEPT);
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_Except &= ~_Flags;
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_Flags |= _Except;
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/* set the new status flags */
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fesetexceptflag(&_Flags, FE_ALL_EXCEPT);
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/* raise the exceptions not masked */
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for (_N = 0; _N < sizeof(_Table) / sizeof(_Table[0]); ++_N)
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{
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if ((_Except & _Table[_N]._Except_Val) != 0)
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{
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_Ans = _Table[_N]._Num / _Table[_N]._Denom;
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}
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}
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return 0;
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}
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__inline int __CRTDECL feupdateenv(_In_ const fenv_t *_Penv)
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{
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int _Except = fetestexcept(FE_ALL_EXCEPT);
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if (fesetenv(_Penv) != 0 || feraiseexcept(_Except) != 0)
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{
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return 1;
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}
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return 0;
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}
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#endif /* !defined(_M_CEE) && !defined(_CRTBLD) */
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#ifdef __cplusplus
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}
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#endif /* __cplusplus */
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#pragma pack(pop)
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#endif /* _FENV */
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