fenv.mh

来自「开放源码的编译器open watcom 1.6.0版的源代码」· MH 代码 · 共 97 行

/***************************************************************************
 * FILE: fenv.h (Floating-point environment)
 *
:include crwat.sp
 *
 * Description: This header is part of the C99 standard library. It
 *              describes the floating-point environment
 ***************************************************************************/
#ifndef _FENV_H_INCLUDED
#define _FENV_H_INCLUDED
:include readonly.sp

#if !defined(__STDC_VERSION__) || __STDC_VERSION__ >= 199901L

#ifndef _COMDEF_H_INCLUDED
 #include <_comdef.h>
#endif

/* type for holding FPU environment */
:include pshpackl.sp
#if defined(__386__)
typedef struct {
    unsigned short control_word;
    unsigned short pad0;
    unsigned short status_word;
    unsigned short pad1;
    unsigned short tag_word;
    unsigned short pad2;
    unsigned int   ins_ptr_offset;
    unsigned short ins_ptr_seg;
    unsigned short opcode;
    unsigned int   op_ptr_offset;
    unsigned short op_ptr_seg;
    unsigned short pad3;
} fenv_t;
#else
typedef struct {
    unsigned short control_word;
    unsigned short status_word;
    unsigned short tag_word;
    unsigned short ins_ptr_offset;
    unsigned short ins_ptr_seg;
    unsigned short op_ptr_offset;
    unsigned short op_ptr_seg;
} fenv_t;
#endif
:include poppack.sp

/* type for holding FPU exception flags */
typedef unsigned short fexcept_t;

/* exception flags */
#define FE_INVALID   1
#define FE_DENORMAL  2
#define FE_DIVBYZERO 4
#define FE_OVERFLOW  8
#define FE_UNDERFLOW 16
#define FE_INEXACT   32

#define FE_ALL_EXCEPT (FE_DIVBYZERO|FE_INEXACT|FE_INVALID|FE_OVERFLOW|FE_UNDERFLOW|FE_DENORMAL)

/* rounding modes */
#define FE_TONEAREST  0x0000
#define FE_DOWNWARD   0x0400
#define FE_TOWARDZERO 0x0C00
#define FE_UPWARD     0x0800

/* default FPU setup */
_WCRTDATA extern const fenv_t __fenv_h_default_environment;
#define FE_DFL_ENV &__fenv_h_default_environment

/* exception handling functions */
_WCRTLINK extern int  feclearexcept( int __excepts );
_WCRTLINK extern int  fegetexceptflag( fexcept_t *__flagp, int __excepts );
_WCRTLINK extern int  feraiseexcept( int __excepts );
_WCRTLINK extern int  fesetexceptflag( const fexcept_t *__flagp, int __excepts );
_WCRTLINK extern int  fetestexcept( int __excepts );

#ifndef NO_EXT_KEYS
/* OW extensions */
_WCRTLINK extern void __feenableexcept( int __excepts );
_WCRTLINK extern void __fedisableexcept( int __excepts );
#endif

/* rounding mode functions */
_WCRTLINK extern int  fegetround( void );
_WCRTLINK extern int  fesetround( int __round );

/* FPU environment functions */
_WCRTLINK extern int  fegetenv( fenv_t *__envp );
_WCRTLINK extern int  feholdexcept( fenv_t *__envp );
_WCRTLINK extern int  fesetenv( const fenv_t *__envp );
_WCRTLINK extern int  feupdateenv( const fenv_t *__envp );

#endif
#endif