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发表于 2022-11-17 15:58:43
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本帖最后由 zhangjinxuan 于 2022-11-17 16:02 编辑
math 内有很多便于数学的函数,常用于数学计算,比如 pow, sqrt, abs 这些很常用
源码?真的要看?那好吧:
- /*
- * math.h
- *
- * ANSI/POSIX + Microsoft compatible mathematical function prototypes,
- * associated macros, and manifest constant definitions.
- *
- * $Id: math.h,v 1e905d042bda 2017/11/28 17:33:30 keith $
- *
- * Written by Colin Peters <colin@bird.fu.is.saga-u.ac.jp>
- * Copyright (C) 1997-2009, 2014-2016, MinGW.org Project.
- *
- *
- * Permission is hereby granted, free of charge, to any person obtaining a
- * copy of this software and associated documentation files (the "Software"),
- * to deal in the Software without restriction, including without limitation
- * the rights to use, copy, modify, merge, publish, distribute, sublicense,
- * and/or sell copies of the Software, and to permit persons to whom the
- * Software is furnished to do so, subject to the following conditions:
- *
- * The above copyright notice, this permission notice, and the following
- * disclaimer shall be included in all copies or substantial portions of
- * the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
- * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
- * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
- * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OF OR OTHER
- * DEALINGS IN THE SOFTWARE.
- *
- */
- #ifndef _MATH_H
- #define _MATH_H
- #pragma GCC system_header
- /* All the headers include this file.
- */
- #include <_mingw.h>
- /* Types for the _exception structure.
- */
- #define _DOMAIN 1 /* domain error in argument */
- #define _SING 2 /* singularity */
- #define _OVERFLOW 3 /* range overflow */
- #define _UNDERFLOW 4 /* range underflow */
- #define _TLOSS 5 /* total loss of precision */
- #define _PLOSS 6 /* partial loss of precision */
- #if ! defined __STRICT_ANSI__ && ! defined _NO_OLDNAMES
- /*
- * Exception types with non-ANSI names for compatibility.
- */
- #define DOMAIN _DOMAIN
- #define SING _SING
- #define OVERFLOW _OVERFLOW
- #define UNDERFLOW _UNDERFLOW
- #define TLOSS _TLOSS
- #define PLOSS _PLOSS
- #endif /* !__STRICT_ANSI__ && !_NO_OLDNAMES */
- #if _POSIX_C_SOURCE || defined _USE_MATH_DEFINES
- /* Traditional/XOPEN math constants (double precison). MSVC makes these
- * available, only if _USE_MATH_DEFINES is specified; POSIX does so also,
- * when _POSIX_C_SOURCE is defined and non-zero, (as will be the case by
- * default in MinGW, unless __STRICT_ANSI__ checking is in effect).
- */
- #define M_E 2.7182818284590452354
- #define M_LOG2E 1.4426950408889634074
- #define M_LOG10E 0.43429448190325182765
- #define M_LN2 0.69314718055994530942
- #define M_LN10 2.30258509299404568402
- #define M_PI 3.14159265358979323846
- #define M_PI_2 1.57079632679489661923
- #define M_PI_4 0.78539816339744830962
- #define M_1_PI 0.31830988618379067154
- #define M_2_PI 0.63661977236758134308
- #define M_2_SQRTPI 1.12837916709551257390
- #define M_SQRT2 1.41421356237309504880
- #define M_SQRT1_2 0.70710678118654752440
- #endif
- /* These are also defined in MinGW float.h; needed here as well,
- * to work around GCC build issues.
- *
- * FIXME: Since they're needed both in MinGW float.h and here,
- * they should be moved to a common "parts" header.
- */
- #if ! defined __STRICT_ANSI__ && ! defined __MINGW_FPCLASS_DEFINED
- #define __MINGW_FPCLASS_DEFINED 1
- /* IEEE 754 classication
- */
- #define _FPCLASS_SNAN 0x0001 /* Signaling "Not a Number" */
- #define _FPCLASS_QNAN 0x0002 /* Quiet "Not a Number" */
- #define _FPCLASS_NINF 0x0004 /* Negative Infinity */
- #define _FPCLASS_NN 0x0008 /* Negative Normal */
- #define _FPCLASS_ND 0x0010 /* Negative Denormal */
- #define _FPCLASS_NZ 0x0020 /* Negative Zero */
- #define _FPCLASS_PZ 0x0040 /* Positive Zero */
- #define _FPCLASS_PD 0x0080 /* Positive Denormal */
- #define _FPCLASS_PN 0x0100 /* Positive Normal */
- #define _FPCLASS_PINF 0x0200 /* Positive Infinity */
- #endif /* !__STRICT_ANSI__ && !__MINGW_FPCLASS_DEFINED */
- #ifndef RC_INVOKED
- _BEGIN_C_DECLS
- /* HUGE_VAL is returned by strtod when the value would overflow the
- * representation of 'double'. There are other uses as well.
- *
- * __imp__HUGE is a pointer to the actual variable _HUGE in
- * MSVCRT.DLL. If we used _HUGE directly we would get a pointer
- * to a thunk function.
- *
- * NOTE: The CRTDLL version uses _HUGE_dll instead.
- */
- #if __MINGW_GNUC_PREREQ(3, 3)
- #define HUGE_VAL __builtin_huge_val()
- #else
- #ifndef __DECLSPEC_SUPPORTED
- #ifdef __MSVCRT__
- extern double *_imp___HUGE;
- #define HUGE_VAL (*_imp___HUGE)
- #else /* CRTDLL */
- extern double *_imp___HUGE_dll;
- #define HUGE_VAL (*_imp___HUGE_dll)
- #endif
- #else /* __DECLSPEC_SUPPORTED */
- #ifdef __MSVCRT__
- __MINGW_IMPORT double _HUGE;
- #define HUGE_VAL _HUGE
- #else /* CRTDLL */
- __MINGW_IMPORT double _HUGE_dll;
- #define HUGE_VAL _HUGE_dll
- #endif
- #endif /* __DECLSPEC_SUPPORTED */
- #endif /* __MINGW_GNUC_PREREQ(3, 3) */
- struct _exception
- {
- int type;
- char *name;
- double arg1;
- double arg2;
- double retval;
- };
- _CRTIMP double __cdecl sin (double);
- _CRTIMP double __cdecl cos (double);
- _CRTIMP double __cdecl tan (double);
- _CRTIMP double __cdecl sinh (double);
- _CRTIMP double __cdecl cosh (double);
- _CRTIMP double __cdecl tanh (double);
- _CRTIMP double __cdecl asin (double);
- _CRTIMP double __cdecl acos (double);
- _CRTIMP double __cdecl atan (double);
- _CRTIMP double __cdecl atan2 (double, double);
- _CRTIMP double __cdecl exp (double);
- _CRTIMP double __cdecl log (double);
- _CRTIMP double __cdecl log10 (double);
- _CRTIMP double __cdecl pow (double, double);
- _CRTIMP double __cdecl sqrt (double);
- _CRTIMP double __cdecl ceil (double);
- _CRTIMP double __cdecl floor (double);
- _CRTIMP double __cdecl fabs (double);
- _CRTIMP double __cdecl ldexp (double, int);
- _CRTIMP double __cdecl frexp (double, int*);
- _CRTIMP double __cdecl modf (double, double*);
- _CRTIMP double __cdecl fmod (double, double);
- #if 0
- /* Excess precision when using a 64-bit mantissa for FPU math ops can
- * cause unexpected results with some of the MSVCRT math functions. For
- * example, unless the function return value is stored (truncating to
- * 53-bit mantissa), calls to pow with both x and y as integral values
- * sometimes produce a non-integral result.
- *
- * One workaround is to reset the FPU env to 53-bit mantissa
- * by a call to fesetenv (FE_PC53_ENV). Amother is to force storage
- * of the return value of individual math functions using wrappers.
- * NB, using these wrappers will disable builtin math functions and
- * hence disable the folding of function results at compile time when
- * arguments are constant.
- */
- #define __DEFINE_FLOAT_STORE_MATHFN_D1(fn1) \
- static __inline__ double \
- __float_store_ ## fn1 (double x) \
- { \
- __volatile__ double res = (fn1) (x); \
- return res; \
- }
- #define __DEFINE_FLOAT_STORE_MATHFN_D2(fn2) \
- static __inline__ double \
- __float_store_ ## fn2 (double x, double y) \
- { \
- __volatile__ double res = (fn2) (x, y); \
- return res; \
- }
- /* For example, here is how to force the result of the pow function
- * to be stored:
- */
- #undef pow
- /* Define the ___float_store_pow function and use it instead of pow().
- */
- __DEFINE_FLOAT_STORE_MATHFN_D2 (pow)
- #define pow __float_store_pow
- #endif
- #ifndef __STRICT_ANSI__
- struct _complex
- { /* Complex number (for _cabs). This is the MS version; the
- * ISO-C99 counterpart, _Complex, is an intrinsic type in GCC,
- * and 'complex' is defined as a macro. See <complex.h>
- */
- double x; /* Real part */
- double y; /* Imaginary part */
- };
- _CRTIMP double __cdecl _cabs (struct _complex);
- _CRTIMP double __cdecl _hypot (double, double);
- _CRTIMP double __cdecl _j0 (double);
- _CRTIMP double __cdecl _j1 (double);
- _CRTIMP double __cdecl _jn (int, double);
- _CRTIMP double __cdecl _y0 (double);
- _CRTIMP double __cdecl _y1 (double);
- _CRTIMP double __cdecl _yn (int, double);
- _CRTIMP int __cdecl _matherr (struct _exception *);
- /* These are also declared in MinGW's <float.h>; we need them
- * here as well to work around GCC build issues.
- */
- /* BEGIN FLOAT.H COPY */
- /*
- * IEEE recommended functions
- */
- _CRTIMP double __cdecl _chgsign (double);
- _CRTIMP double __cdecl _copysign (double, double);
- _CRTIMP double __cdecl _logb (double);
- _CRTIMP double __cdecl _nextafter (double, double);
- _CRTIMP double __cdecl _scalb (double, long);
- _CRTIMP int __cdecl _finite (double);
- _CRTIMP int __cdecl _fpclass (double);
- _CRTIMP int __cdecl _isnan (double);
- /* END FLOAT.H COPY */
- #ifndef _NO_OLDNAMES
- /* Non-underscored versions of non-ANSI functions.
- * These reside in liboldnames.a.
- */
- _CRTIMP double __cdecl j0 (double);
- _CRTIMP double __cdecl j1 (double);
- _CRTIMP double __cdecl jn (int, double);
- _CRTIMP double __cdecl y0 (double);
- _CRTIMP double __cdecl y1 (double);
- _CRTIMP double __cdecl yn (int, double);
- _CRTIMP double __cdecl chgsign (double);
- /*
- * scalb() is a GCC built-in.
- * Exclude this _scalb() stub; the semantics are incompatible
- * with the built-in implementation.
- *
- _CRTIMP double __cdecl scalb (double, long);
- *
- */
- _CRTIMP int __cdecl finite (double);
- _CRTIMP int __cdecl fpclass (double);
- #define FP_SNAN _FPCLASS_SNAN
- #define FP_QNAN _FPCLASS_QNAN
- #define FP_NINF _FPCLASS_NINF
- #define FP_PINF _FPCLASS_PINF
- #define FP_NDENORM _FPCLASS_ND
- #define FP_PDENORM _FPCLASS_PD
- #define FP_NZERO _FPCLASS_NZ
- #define FP_PZERO _FPCLASS_PZ
- #define FP_NNORM _FPCLASS_NN
- #define FP_PNORM _FPCLASS_PN
- #endif /* !_NO_OLDNAMES */
- #if _WIN32_WINNT >= _WIN32_WINNT_WINXP || __MSVCRT_VERSION__ >= __MSVCR70_DLL
- /*
- * This requires WinXP, or MSVCR70.DLL, or later.
- */
- _CRTIMP int __cdecl _set_SSE2_enable (int);
- #endif /* >= WINXP || >= __MSVCR70_DLL */
- #endif /* !__STRICT_ANSI__ */
- #if defined __cplusplus || defined _ISOC99_SOURCE
- # if __MINGW_GNUC_PREREQ(3, 3)
- # define HUGE_VALF __builtin_huge_valf()
- # define HUGE_VALL __builtin_huge_vall()
- # define INFINITY __builtin_inf()
- # define NAN __builtin_nan("")
- # else
- extern const float __INFF;
- extern const long double __INFL;
- extern const double __QNAN;
- # define HUGE_VALF __INFF
- # define HUGE_VALL __INFL
- # define INFINITY HUGE_VALF
- # define NAN __QNAN
- # endif /* __MINGW_GNUC_PREREQ(3, 3) */
- /* Use the compiler's internal definition for FLT_EVAL_METHOD, if one
- * is available, to establish appropriate float_t and double_t typedefs;
- * in the case of GCC, this is specified as __FLT_EVAL_METHOD__, which
- * is expected to be assigned standardized values of 0, 1, or 2, (or
- * exceptionally, a value of -1, representing indeterminacy).
- */
- #if ! defined __FLT_EVAL_METHOD__ || __valueless(__FLT_EVAL_METHOD__) \
- || (__FLT_EVAL_METHOD__ - 0) < 0 || (__FLT_EVAL_METHOD__ - 0) > 1
- /* __FLT_EVAL_METHOD__ has not been defined, or it is defined with no
- * value, or with a value of -1 (or less), or a value of 2 or more; in
- * the specific case of a value of 2, this represents an explicit choice
- * of the IX387 FPU configuration, while in each of the other cases, we
- * implicitly fall back to this same default configuration.
- *
- * NOTE: this configuration is correct for X87 FPU computations, (for
- * which __FLT_EVAL_METHOD__ is correctly specified as 2); however...
- */
- # if defined __FLT_EVAL_METHOD__ && (__FLT_EVAL_METHOD__ - 0) != 2
- /* ...due to a GCC bug, introduced in GCC-6 and persisting into later
- * versions, it may be selected via __FLT_EVAL_METHOD__ == -1, for the
- * case of the "-msse -mfpmath=sse" option combination. In this case,
- * it is (at best) an unsatisfactory compromise; to avoid it, you may
- * prefer to adopt "-mfpmath=387", or "-msse2 -mfpmath=sse" instead.
- */
- # warning "Default FLT_EVAL_METHOD is inderminate; assuming X87 semantics."
- # endif
- typedef long double float_t;
- typedef long double double_t;
- #else
- /* __FLT_EVAL_METHOD__ must have been defined with an explicit value
- * of either 0 or 1; select the corresponding SSE configuration which
- * is applicable in each case.
- */
- # if __FLT_EVAL_METHOD__ == 0
- typedef float float_t;
- typedef double double_t;
- # else /* __FLT_EVAL_METHOD__ == 1 */
- typedef double float_t;
- typedef double double_t;
- # endif
- #endif
- /* 7.12.3.1
- * Return values for fpclassify.
- * These are based on Intel x87 fpu condition codes
- * in the high byte of status word and differ from
- * the return values for MS IEEE 754 extension _fpclass()
- */
- #define FP_NAN 0x0100
- #define FP_NORMAL 0x0400
- #define FP_INFINITE (FP_NAN | FP_NORMAL)
- #define FP_ZERO 0x4000
- #define FP_SUBNORMAL (FP_NORMAL | FP_ZERO)
- /* 0x0200 is signbit mask */
- /* We can't inline float or double, because we want to ensure
- * truncation to semantic type before classification; (a normal
- * long double value might become subnormal when converted to
- * double, and zero when converted to float.)
- */
- extern int __cdecl __fpclassifyf (float);
- extern int __cdecl __fpclassify (double);
- extern int __cdecl __fpclassifyl (long double);
- #ifndef __NO_INLINE__
- __CRT_INLINE int __cdecl __fpclassifyl (long double x){
- unsigned short sw;
- __asm__ ("fxam; fstsw %%ax;" : "=a" (sw): "t" (x));
- return sw & (FP_NAN | FP_NORMAL | FP_ZERO );
- }
- #endif
- #define fpclassify(x) (sizeof (x) == sizeof (float) ? __fpclassifyf (x) \
- : sizeof (x) == sizeof (double) ? __fpclassify (x) \
- : __fpclassifyl (x))
- /* 7.12.3.2 */
- #define isfinite(x) ((fpclassify(x) & FP_NAN) == 0)
- /* 7.12.3.3 */
- #define isinf(x) (fpclassify(x) == FP_INFINITE)
- /* 7.12.3.4 */
- /* We don't need to worry about truncation here:
- * a NaN stays a NaN.
- */
- extern int __cdecl __isnan (double);
- extern int __cdecl __isnanf (float);
- extern int __cdecl __isnanl (long double);
- #ifndef __NO_INLINE__
- __CRT_INLINE int __cdecl __isnan (double _x)
- {
- unsigned short sw;
- __asm__ ("fxam;"
- "fstsw %%ax": "=a" (sw) : "t" (_x));
- return (sw & (FP_NAN | FP_NORMAL | FP_INFINITE | FP_ZERO | FP_SUBNORMAL))
- == FP_NAN;
- }
- __CRT_INLINE int __cdecl __isnanf (float _x)
- {
- unsigned short sw;
- __asm__ ("fxam;"
- "fstsw %%ax": "=a" (sw) : "t" (_x));
- return (sw & (FP_NAN | FP_NORMAL | FP_INFINITE | FP_ZERO | FP_SUBNORMAL))
- == FP_NAN;
- }
- __CRT_INLINE int __cdecl __isnanl (long double _x)
- {
- unsigned short sw;
- __asm__ ("fxam;"
- "fstsw %%ax": "=a" (sw) : "t" (_x));
- return (sw & (FP_NAN | FP_NORMAL | FP_INFINITE | FP_ZERO | FP_SUBNORMAL))
- == FP_NAN;
- }
- #endif
- #define isnan(x) (sizeof (x) == sizeof (float) ? __isnanf (x) \
- : sizeof (x) == sizeof (double) ? __isnan (x) \
- : __isnanl (x))
- /* 7.12.3.5 */
- #define isnormal(x) (fpclassify(x) == FP_NORMAL)
- /* 7.12.3.6 The signbit macro */
- extern int __cdecl __signbit (double);
- extern int __cdecl __signbitf (float);
- extern int __cdecl __signbitl (long double);
- #ifndef __NO_INLINE__
- __CRT_INLINE int __cdecl __signbit (double x) {
- unsigned short stw;
- __asm__ ( "fxam; fstsw %%ax;": "=a" (stw) : "t" (x));
- return (stw & 0x0200) != 0;
- }
- __CRT_INLINE int __cdecl __signbitf (float x) {
- unsigned short stw;
- __asm__ ("fxam; fstsw %%ax;": "=a" (stw) : "t" (x));
- return (stw & 0x0200) != 0;
- }
- __CRT_INLINE int __cdecl __signbitl (long double x) {
- unsigned short stw;
- __asm__ ("fxam; fstsw %%ax;": "=a" (stw) : "t" (x));
- return (stw & 0x0200) != 0;
- }
- #endif
- #define signbit(x) (sizeof (x) == sizeof (float) ? __signbitf (x) \
- : sizeof (x) == sizeof (double) ? __signbit (x) \
- : __signbitl (x))
- /* 7.12.4 Trigonometric functions: double in C89
- */
- extern float __cdecl sinf (float);
- extern long double __cdecl sinl (long double);
- extern float __cdecl cosf (float);
- extern long double __cdecl cosl (long double);
- extern float __cdecl tanf (float);
- extern long double __cdecl tanl (long double);
- extern float __cdecl asinf (float);
- extern long double __cdecl asinl (long double);
- extern float __cdecl acosf (float);
- extern long double __cdecl acosl (long double);
- extern float __cdecl atanf (float);
- extern long double __cdecl atanl (long double);
- extern float __cdecl atan2f (float, float);
- extern long double __cdecl atan2l (long double, long double);
- /* 7.12.5 Hyperbolic functions: double in C89
- */
- extern float __cdecl sinhf (float);
- #ifndef __NO_INLINE__
- __CRT_INLINE float __cdecl sinhf (float x)
- {return (float) sinh (x);}
- #endif
- extern long double __cdecl sinhl (long double);
- extern float __cdecl coshf (float);
- #ifndef __NO_INLINE__
- __CRT_INLINE float __cdecl coshf (float x)
- {return (float) cosh (x);}
- #endif
- extern long double __cdecl coshl (long double);
- extern float __cdecl tanhf (float);
- #ifndef __NO_INLINE__
- __CRT_INLINE float __cdecl tanhf (float x)
- {return (float) tanh (x);}
- #endif
- extern long double __cdecl tanhl (long double);
- /* Inverse hyperbolic trig functions */
- /* 7.12.5.1 */
- extern double __cdecl acosh (double);
- extern float __cdecl acoshf (float);
- extern long double __cdecl acoshl (long double);
- /* 7.12.5.2 */
- extern double __cdecl asinh (double);
- extern float __cdecl asinhf (float);
- extern long double __cdecl asinhl (long double);
- /* 7.12.5.3 */
- extern double __cdecl atanh (double);
- extern float __cdecl atanhf (float);
- extern long double __cdecl atanhl (long double);
- /* Exponentials and logarithms */
- /* 7.12.6.1 Double in C89 */
- extern float __cdecl expf (float);
- #ifndef __NO_INLINE__
- __CRT_INLINE float __cdecl expf (float x)
- {return (float) exp (x);}
- #endif
- extern long double __cdecl expl (long double);
- /* 7.12.6.2 */
- extern double __cdecl exp2(double);
- extern float __cdecl exp2f(float);
- extern long double __cdecl exp2l(long double);
- /* 7.12.6.3 The expm1 functions */
- /* TODO: These could be inlined */
- extern double __cdecl expm1(double);
- extern float __cdecl expm1f(float);
- extern long double __cdecl expm1l(long double);
- /* 7.12.6.4 Double in C89 */
- extern float __cdecl frexpf (float, int*);
- #ifndef __NO_INLINE__
- __CRT_INLINE float __cdecl frexpf (float x, int* expn)
- {return (float) frexp (x, expn);}
- #endif
- extern long double __cdecl frexpl (long double, int*);
- /* 7.12.6.5 */
- #define FP_ILOGB0 ((int)0x80000000)
- #define FP_ILOGBNAN ((int)0x80000000)
- extern int __cdecl ilogb (double);
- extern int __cdecl ilogbf (float);
- extern int __cdecl ilogbl (long double);
- /* 7.12.6.6 Double in C89 */
- extern float __cdecl ldexpf (float, int);
- #ifndef __NO_INLINE__
- __CRT_INLINE float __cdecl ldexpf (float x, int expn)
- {return (float) ldexp (x, expn);}
- #endif
- extern long double __cdecl ldexpl (long double, int);
- /* 7.12.6.7 Double in C89 */
- extern float __cdecl logf (float);
- extern long double __cdecl logl (long double);
- /* 7.12.6.8 Double in C89 */
- extern float __cdecl log10f (float);
- extern long double __cdecl log10l (long double);
- /* 7.12.6.9 */
- extern double __cdecl log1p(double);
- extern float __cdecl log1pf(float);
- extern long double __cdecl log1pl(long double);
- /* 7.12.6.10 */
- extern double __cdecl log2 (double);
- extern float __cdecl log2f (float);
- extern long double __cdecl log2l (long double);
- /* 7.12.6.11 */
- extern double __cdecl logb (double);
- extern float __cdecl logbf (float);
- extern long double __cdecl logbl (long double);
- /* Inline versions. GCC-4.0+ can do a better fast-math optimization
- * with __builtins.
- */
- #ifndef __NO_INLINE__
- #if !(__MINGW_GNUC_PREREQ (4, 0) && defined __FAST_MATH__ )
- __CRT_INLINE double __cdecl logb (double x)
- {
- double res;
- __asm__ ("fxtract\n\t"
- "fstp %%st" : "=t" (res) : "0" (x));
- return res;
- }
- __CRT_INLINE float __cdecl logbf (float x)
- {
- float res;
- __asm__ ("fxtract\n\t"
- "fstp %%st" : "=t" (res) : "0" (x));
- return res;
- }
- __CRT_INLINE long double __cdecl logbl (long double x)
- {
- long double res;
- __asm__ ("fxtract\n\t"
- "fstp %%st" : "=t" (res) : "0" (x));
- return res;
- }
- #endif /* !__FAST_MATH__ || !__MINGW_GNUC_PREREQ (4, 0) */
- #endif /* !__NO_INLINE__ */
- /* 7.12.6.12 Double in C89 */
- extern float __cdecl modff (float, float*);
- extern long double __cdecl modfl (long double, long double*);
- /* 7.12.6.13 */
- extern double __cdecl scalbn (double, int);
- extern float __cdecl scalbnf (float, int);
- extern long double __cdecl scalbnl (long double, int);
- extern double __cdecl scalbln (double, long);
- extern float __cdecl scalblnf (float, long);
- extern long double __cdecl scalblnl (long double, long);
- /* 7.12.7.1 */
- /* Implementations adapted from Cephes versions */
- extern double __cdecl cbrt (double);
- extern float __cdecl cbrtf (float);
- extern long double __cdecl cbrtl (long double);
- /* 7.12.7.2 The fabs functions: Double in C89 */
- extern float __cdecl fabsf (float x);
- extern long double __cdecl fabsl (long double x);
- /* 7.12.7.3 */
- extern double __cdecl hypot (double, double); /* in libmoldname.a */
- extern float __cdecl hypotf (float, float);
- extern long double __cdecl hypotl (long double, long double);
- /* 7.12.7.4 The pow functions. Double in C89 */
- extern float __cdecl powf (float, float);
- extern long double __cdecl powl (long double, long double);
- /* 7.12.7.5 The sqrt functions. Double in C89. */
- extern float __cdecl sqrtf (float);
- extern long double __cdecl sqrtl (long double);
- /* 7.12.8.1 The erf functions */
- extern double __cdecl erf (double);
- extern float __cdecl erff (float);
- extern long double __cdecl erfl (long double);
- /* 7.12.8.2 The erfc functions */
- extern double __cdecl erfc (double);
- extern float __cdecl erfcf (float);
- extern long double __cdecl erfcl (long double);
- /* 7.12.8.3 The lgamma functions */
- extern double __cdecl lgamma (double);
- extern float __cdecl lgammaf (float);
- extern long double __cdecl lgammal (long double);
- /* 7.12.8.4 The tgamma functions */
- extern double __cdecl tgamma (double);
- extern float __cdecl tgammaf (float);
- extern long double __cdecl tgammal (long double);
- /* 7.12.9.1 Double in C89 */
- extern float __cdecl ceilf (float);
- extern long double __cdecl ceill (long double);
- /* 7.12.9.2 Double in C89 */
- extern float __cdecl floorf (float);
- extern long double __cdecl floorl (long double);
- /* 7.12.9.3 */
- extern double __cdecl nearbyint ( double);
- extern float __cdecl nearbyintf (float);
- extern long double __cdecl nearbyintl (long double);
- /* 7.12.9.4 */
- /* round, using fpu control word settings */
- extern double __cdecl rint (double);
- extern float __cdecl rintf (float);
- extern long double __cdecl rintl (long double);
- /* 7.12.9.5 */
- extern long __cdecl lrint (double);
- extern long __cdecl lrintf (float);
- extern long __cdecl lrintl (long double);
- extern long long __cdecl llrint (double);
- extern long long __cdecl llrintf (float);
- extern long long __cdecl llrintl (long double);
- /* Inline versions of above.
- * GCC 4.0+ can do a better fast-math job with __builtins.
- */
- #ifndef __NO_INLINE__
- #if !(__MINGW_GNUC_PREREQ (4, 0) && defined __FAST_MATH__ )
- __CRT_INLINE double __cdecl rint (double x)
- {
- double retval;
- __asm__ ("frndint;": "=t" (retval) : "0" (x));
- return retval;
- }
- __CRT_INLINE float __cdecl rintf (float x)
- {
- float retval;
- __asm__ ("frndint;" : "=t" (retval) : "0" (x) );
- return retval;
- }
- __CRT_INLINE long double __cdecl rintl (long double x)
- {
- long double retval;
- __asm__ ("frndint;" : "=t" (retval) : "0" (x) );
- return retval;
- }
- __CRT_INLINE long __cdecl lrint (double x)
- {
- long retval;
- __asm__ __volatile__
- ("fistpl %0" : "=m" (retval) : "t" (x) : "st");
- return retval;
- }
- __CRT_INLINE long __cdecl lrintf (float x)
- {
- long retval;
- __asm__ __volatile__
- ("fistpl %0" : "=m" (retval) : "t" (x) : "st");
- return retval;
- }
- __CRT_INLINE long __cdecl lrintl (long double x)
- {
- long retval;
- __asm__ __volatile__
- ("fistpl %0" : "=m" (retval) : "t" (x) : "st");
- return retval;
- }
- __CRT_INLINE long long __cdecl llrint (double x)
- {
- long long retval;
- __asm__ __volatile__
- ("fistpll %0" : "=m" (retval) : "t" (x) : "st");
- return retval;
- }
- __CRT_INLINE long long __cdecl llrintf (float x)
- {
- long long retval;
- __asm__ __volatile__
- ("fistpll %0" : "=m" (retval) : "t" (x) : "st");
- return retval;
- }
- __CRT_INLINE long long __cdecl llrintl (long double x)
- {
- long long retval;
- __asm__ __volatile__
- ("fistpll %0" : "=m" (retval) : "t" (x) : "st");
- return retval;
- }
- #endif /* !__FAST_MATH__ || !__MINGW_GNUC_PREREQ (4,0) */
- #endif /* !__NO_INLINE__ */
- /* 7.12.9.6 */
- /* round away from zero, regardless of fpu control word settings */
- extern double __cdecl round (double);
- extern float __cdecl roundf (float);
- extern long double __cdecl roundl (long double);
- /* 7.12.9.7 */
- extern long __cdecl lround (double);
- extern long __cdecl lroundf (float);
- extern long __cdecl lroundl (long double);
- extern long long __cdecl llround (double);
- extern long long __cdecl llroundf (float);
- extern long long __cdecl llroundl (long double);
- /* 7.12.9.8 */
- /* round towards zero, regardless of fpu control word settings */
- extern double __cdecl trunc (double);
- extern float __cdecl truncf (float);
- extern long double __cdecl truncl (long double);
- /* 7.12.10.1 Double in C89 */
- extern float __cdecl fmodf (float, float);
- extern long double __cdecl fmodl (long double, long double);
- /* 7.12.10.2 */
- extern double __cdecl remainder (double, double);
- extern float __cdecl remainderf (float, float);
- extern long double __cdecl remainderl (long double, long double);
- /* 7.12.10.3 */
- extern double __cdecl remquo(double, double, int *);
- extern float __cdecl remquof(float, float, int *);
- extern long double __cdecl remquol(long double, long double, int *);
- /* 7.12.11.1 */
- extern double __cdecl copysign (double, double); /* in libmoldname.a */
- extern float __cdecl copysignf (float, float);
- extern long double __cdecl copysignl (long double, long double);
- /* 7.12.11.2 Return a NaN */
- extern double __cdecl nan(const char *tagp);
- extern float __cdecl nanf(const char *tagp);
- extern long double __cdecl nanl(const char *tagp);
- #ifndef __STRICT_ANSI__
- #define _nan() nan("")
- #define _nanf() nanf("")
- #define _nanl() nanl("")
- #endif
- /* 7.12.11.3 */
- extern double __cdecl nextafter (double, double); /* in libmoldname.a */
- extern float __cdecl nextafterf (float, float);
- extern long double __cdecl nextafterl (long double, long double);
- /* 7.12.11.4 The nexttoward functions */
- extern double __cdecl nexttoward (double, long double);
- extern float __cdecl nexttowardf (float, long double);
- extern long double __cdecl nexttowardl (long double, long double);
- /* 7.12.12.1 */
- /* x > y ? (x - y) : 0.0 */
- extern double __cdecl fdim (double x, double y);
- extern float __cdecl fdimf (float x, float y);
- extern long double __cdecl fdiml (long double x, long double y);
- /* fmax and fmin.
- NaN arguments are treated as missing data: if one argument is a NaN
- and the other numeric, then these functions choose the numeric
- value. */
- /* 7.12.12.2 */
- extern double __cdecl fmax (double, double);
- extern float __cdecl fmaxf (float, float);
- extern long double __cdecl fmaxl (long double, long double);
- /* 7.12.12.3 */
- extern double __cdecl fmin (double, double);
- extern float __cdecl fminf (float, float);
- extern long double __cdecl fminl (long double, long double);
- /* 7.12.13.1 */
- /* return x * y + z as a ternary op */
- extern double __cdecl fma (double, double, double);
- extern float __cdecl fmaf (float, float, float);
- extern long double __cdecl fmal (long double, long double, long double);
- /* 7.12.14
- * With these functions, comparisons involving quiet NaNs set the FP
- * condition code to "unordered". The IEEE floating-point spec
- * dictates that the result of floating-point comparisons should be
- * false whenever a NaN is involved, with the exception of the != op,
- * which always returns true: yes, (NaN != NaN) is true).
- */
- #if __GNUC__ >= 3
- #define isgreater(x, y) __builtin_isgreater(x, y)
- #define isgreaterequal(x, y) __builtin_isgreaterequal(x, y)
- #define isless(x, y) __builtin_isless(x, y)
- #define islessequal(x, y) __builtin_islessequal(x, y)
- #define islessgreater(x, y) __builtin_islessgreater(x, y)
- #define isunordered(x, y) __builtin_isunordered(x, y)
- #else /* __GNUC__ < 3 */
- /* helper */
- extern int __cdecl __fp_unordered_compare (long double, long double);
- #ifndef __NO_INLINE__
- __CRT_INLINE int __cdecl
- __fp_unordered_compare (long double x, long double y){
- unsigned short retval;
- __asm__ ("fucom %%st(1);"
- "fnstsw;": "=a" (retval) : "t" (x), "u" (y));
- return retval;
- }
- #endif /* !__NO_INLINE__ */
- #define isgreater(x, y) ((__fp_unordered_compare(x, y) & 0x4500) == 0)
- #define isless(x, y) ((__fp_unordered_compare(y, x) & 0x4500) == 0)
- #define isgreaterequal(x, y) ((__fp_unordered_compare(x, y) & FP_INFINITE) == 0)
- #define islessequal(x, y) ((__fp_unordered_compare(y, x) & FP_INFINITE) == 0)
- #define islessgreater(x, y) ((__fp_unordered_compare(x, y) & FP_SUBNORMAL) == 0)
- #define isunordered(x, y) ((__fp_unordered_compare(x, y) & 0x4500) == 0x4500)
- #endif /* __GNUC__ < 3 */
- #endif /* __cplusplus || _ISOC99_SOURCE */
- _END_C_DECLS
- #endif /* ! RC_INVOKED */
- #endif /* !_MATH_H: $RCSfile: math.h,v $: end of file */
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还有啊,它的含义我怎么知道?我又不是这个编译器的开发人员,含义这个问题真的很难,我无法解答,这种代码估计只有大学生才能看懂吧,不过你就可能是大学生,啊这……我小学。 |
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