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794e7d1ab2
In GH-2866, _Py_Bit_Length() was added to pymath.h for lack of a better location. GH-20518 added a more appropriate header file for bit utilities. It also shows how to properly use intrinsics. This allows reconsidering bpo-29782. * Move the function to the new header. * Changed return type to match __builtin_clzl() and reviewed usage. * Use intrinsics where available. * Pick a fallback implementation suitable for inlining.
231 lines
8.1 KiB
C
231 lines
8.1 KiB
C
#ifndef Py_PYMATH_H
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#define Py_PYMATH_H
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#include "pyconfig.h" /* include for defines */
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/**************************************************************************
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Symbols and macros to supply platform-independent interfaces to mathematical
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functions and constants
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**************************************************************************/
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/* Python provides implementations for copysign, round and hypot in
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* Python/pymath.c just in case your math library doesn't provide the
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* functions.
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*
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*Note: PC/pyconfig.h defines copysign as _copysign
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*/
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#ifndef HAVE_COPYSIGN
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extern double copysign(double, double);
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#endif
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#ifndef HAVE_ROUND
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extern double round(double);
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#endif
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#ifndef HAVE_HYPOT
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extern double hypot(double, double);
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#endif
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/* extra declarations */
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#ifndef _MSC_VER
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#ifndef __STDC__
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extern double fmod (double, double);
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extern double frexp (double, int *);
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extern double ldexp (double, int);
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extern double modf (double, double *);
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extern double pow(double, double);
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#endif /* __STDC__ */
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#endif /* _MSC_VER */
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/* High precision definition of pi and e (Euler)
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* The values are taken from libc6's math.h.
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*/
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#ifndef Py_MATH_PIl
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#define Py_MATH_PIl 3.1415926535897932384626433832795029L
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#endif
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#ifndef Py_MATH_PI
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#define Py_MATH_PI 3.14159265358979323846
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#endif
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#ifndef Py_MATH_El
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#define Py_MATH_El 2.7182818284590452353602874713526625L
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#endif
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#ifndef Py_MATH_E
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#define Py_MATH_E 2.7182818284590452354
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#endif
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/* Tau (2pi) to 40 digits, taken from tauday.com/tau-digits. */
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#ifndef Py_MATH_TAU
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#define Py_MATH_TAU 6.2831853071795864769252867665590057683943L
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#endif
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/* On x86, Py_FORCE_DOUBLE forces a floating-point number out of an x87 FPU
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register and into a 64-bit memory location, rounding from extended
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precision to double precision in the process. On other platforms it does
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nothing. */
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/* we take double rounding as evidence of x87 usage */
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#ifndef Py_LIMITED_API
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#ifndef Py_FORCE_DOUBLE
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# ifdef X87_DOUBLE_ROUNDING
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PyAPI_FUNC(double) _Py_force_double(double);
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# define Py_FORCE_DOUBLE(X) (_Py_force_double(X))
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# else
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# define Py_FORCE_DOUBLE(X) (X)
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# endif
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#endif
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#endif
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#ifndef Py_LIMITED_API
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#ifdef HAVE_GCC_ASM_FOR_X87
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PyAPI_FUNC(unsigned short) _Py_get_387controlword(void);
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PyAPI_FUNC(void) _Py_set_387controlword(unsigned short);
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#endif
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#endif
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/* Py_IS_NAN(X)
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* Return 1 if float or double arg is a NaN, else 0.
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* Caution:
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* X is evaluated more than once.
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* This may not work on all platforms. Each platform has *some*
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* way to spell this, though -- override in pyconfig.h if you have
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* a platform where it doesn't work.
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* Note: PC/pyconfig.h defines Py_IS_NAN as _isnan
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*/
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#ifndef Py_IS_NAN
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#if defined HAVE_DECL_ISNAN && HAVE_DECL_ISNAN == 1
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#define Py_IS_NAN(X) isnan(X)
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#else
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#define Py_IS_NAN(X) ((X) != (X))
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#endif
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#endif
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/* Py_IS_INFINITY(X)
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* Return 1 if float or double arg is an infinity, else 0.
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* Caution:
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* X is evaluated more than once.
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* This implementation may set the underflow flag if |X| is very small;
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* it really can't be implemented correctly (& easily) before C99.
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* Override in pyconfig.h if you have a better spelling on your platform.
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* Py_FORCE_DOUBLE is used to avoid getting false negatives from a
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* non-infinite value v sitting in an 80-bit x87 register such that
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* v becomes infinite when spilled from the register to 64-bit memory.
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* Note: PC/pyconfig.h defines Py_IS_INFINITY as _isinf
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*/
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#ifndef Py_IS_INFINITY
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# if defined HAVE_DECL_ISINF && HAVE_DECL_ISINF == 1
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# define Py_IS_INFINITY(X) isinf(X)
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# else
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# define Py_IS_INFINITY(X) ((X) && \
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(Py_FORCE_DOUBLE(X)*0.5 == Py_FORCE_DOUBLE(X)))
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# endif
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#endif
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/* Py_IS_FINITE(X)
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* Return 1 if float or double arg is neither infinite nor NAN, else 0.
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* Some compilers (e.g. VisualStudio) have intrinsics for this, so a special
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* macro for this particular test is useful
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* Note: PC/pyconfig.h defines Py_IS_FINITE as _finite
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*/
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#ifndef Py_IS_FINITE
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#if defined HAVE_DECL_ISFINITE && HAVE_DECL_ISFINITE == 1
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#define Py_IS_FINITE(X) isfinite(X)
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#elif defined HAVE_FINITE
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#define Py_IS_FINITE(X) finite(X)
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#else
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#define Py_IS_FINITE(X) (!Py_IS_INFINITY(X) && !Py_IS_NAN(X))
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#endif
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#endif
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/* HUGE_VAL is supposed to expand to a positive double infinity. Python
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* uses Py_HUGE_VAL instead because some platforms are broken in this
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* respect. We used to embed code in pyport.h to try to worm around that,
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* but different platforms are broken in conflicting ways. If you're on
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* a platform where HUGE_VAL is defined incorrectly, fiddle your Python
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* config to #define Py_HUGE_VAL to something that works on your platform.
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*/
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#ifndef Py_HUGE_VAL
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#define Py_HUGE_VAL HUGE_VAL
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#endif
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/* Py_NAN
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* A value that evaluates to a NaN. On IEEE 754 platforms INF*0 or
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* INF/INF works. Define Py_NO_NAN in pyconfig.h if your platform
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* doesn't support NaNs.
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*/
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#if !defined(Py_NAN) && !defined(Py_NO_NAN)
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#if !defined(__INTEL_COMPILER)
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#define Py_NAN (Py_HUGE_VAL * 0.)
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#else /* __INTEL_COMPILER */
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#if defined(ICC_NAN_STRICT)
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#pragma float_control(push)
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#pragma float_control(precise, on)
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#pragma float_control(except, on)
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#if defined(_MSC_VER)
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__declspec(noinline)
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#else /* Linux */
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__attribute__((noinline))
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#endif /* _MSC_VER */
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static double __icc_nan()
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{
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return sqrt(-1.0);
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}
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#pragma float_control (pop)
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#define Py_NAN __icc_nan()
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#else /* ICC_NAN_RELAXED as default for Intel Compiler */
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static const union { unsigned char buf[8]; double __icc_nan; } __nan_store = {0,0,0,0,0,0,0xf8,0x7f};
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#define Py_NAN (__nan_store.__icc_nan)
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#endif /* ICC_NAN_STRICT */
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#endif /* __INTEL_COMPILER */
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#endif
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/* Py_OVERFLOWED(X)
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* Return 1 iff a libm function overflowed. Set errno to 0 before calling
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* a libm function, and invoke this macro after, passing the function
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* result.
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* Caution:
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* This isn't reliable. C99 no longer requires libm to set errno under
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* any exceptional condition, but does require +- HUGE_VAL return
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* values on overflow. A 754 box *probably* maps HUGE_VAL to a
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* double infinity, and we're cool if that's so, unless the input
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* was an infinity and an infinity is the expected result. A C89
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* system sets errno to ERANGE, so we check for that too. We're
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* out of luck if a C99 754 box doesn't map HUGE_VAL to +Inf, or
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* if the returned result is a NaN, or if a C89 box returns HUGE_VAL
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* in non-overflow cases.
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* X is evaluated more than once.
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* Some platforms have better way to spell this, so expect some #ifdef'ery.
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*
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* OpenBSD uses 'isinf()' because a compiler bug on that platform causes
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* the longer macro version to be mis-compiled. This isn't optimal, and
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* should be removed once a newer compiler is available on that platform.
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* The system that had the failure was running OpenBSD 3.2 on Intel, with
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* gcc 2.95.3.
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*
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* According to Tim's checkin, the FreeBSD systems use isinf() to work
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* around a FPE bug on that platform.
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*/
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#if defined(__FreeBSD__) || defined(__OpenBSD__)
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#define Py_OVERFLOWED(X) isinf(X)
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#else
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#define Py_OVERFLOWED(X) ((X) != 0.0 && (errno == ERANGE || \
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(X) == Py_HUGE_VAL || \
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(X) == -Py_HUGE_VAL))
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#endif
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/* Return whether integral type *type* is signed or not. */
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#define _Py_IntegralTypeSigned(type) ((type)(-1) < 0)
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/* Return the maximum value of integral type *type*. */
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#define _Py_IntegralTypeMax(type) ((_Py_IntegralTypeSigned(type)) ? (((((type)1 << (sizeof(type)*CHAR_BIT - 2)) - 1) << 1) + 1) : ~(type)0)
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/* Return the minimum value of integral type *type*. */
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#define _Py_IntegralTypeMin(type) ((_Py_IntegralTypeSigned(type)) ? -_Py_IntegralTypeMax(type) - 1 : 0)
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/* Check whether *v* is in the range of integral type *type*. This is most
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* useful if *v* is floating-point, since demoting a floating-point *v* to an
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* integral type that cannot represent *v*'s integral part is undefined
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* behavior. */
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#define _Py_InIntegralTypeRange(type, v) (_Py_IntegralTypeMin(type) <= v && v <= _Py_IntegralTypeMax(type))
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#endif /* Py_PYMATH_H */
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