mirror of https://github.com/python/cpython
185 lines
7.7 KiB
C
185 lines
7.7 KiB
C
#ifndef Py_INTERNAL_PYMATH_H
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#define Py_INTERNAL_PYMATH_H
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#ifdef __cplusplus
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extern "C" {
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#endif
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#ifndef Py_BUILD_CORE
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# error "this header requires Py_BUILD_CORE define"
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#endif
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// Extra declarations
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#if !defined(_MSC_VER) && !defined(__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 // !defined(_MSC_VER) && !defined(__STDC__)
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/* _Py_ADJUST_ERANGE1(x)
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* _Py_ADJUST_ERANGE2(x, y)
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* Set errno to 0 before calling a libm function, and invoke one of these
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* macros after, passing the function result(s) (_Py_ADJUST_ERANGE2 is useful
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* for functions returning complex results). This makes two kinds of
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* adjustments to errno: (A) If it looks like the platform libm set
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* errno=ERANGE due to underflow, clear errno. (B) If it looks like the
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* platform libm overflowed but didn't set errno, force errno to ERANGE. In
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* effect, we're trying to force a useful implementation of C89 errno
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* behavior.
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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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*/
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static inline void _Py_ADJUST_ERANGE1(double x)
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{
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if (errno == 0) {
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if (x == Py_HUGE_VAL || x == -Py_HUGE_VAL) {
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errno = ERANGE;
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}
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}
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else if (errno == ERANGE && x == 0.0) {
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errno = 0;
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}
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}
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static inline void _Py_ADJUST_ERANGE2(double x, double y)
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{
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if (x == Py_HUGE_VAL || x == -Py_HUGE_VAL ||
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y == Py_HUGE_VAL || y == -Py_HUGE_VAL)
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{
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if (errno == 0) {
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errno = ERANGE;
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}
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}
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else if (errno == ERANGE) {
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errno = 0;
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}
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}
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// Return whether integral type *type* is signed or not.
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#define _Py_IntegralTypeSigned(type) \
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((type)(-1) < 0)
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// Return the maximum value of integral type *type*.
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#define _Py_IntegralTypeMax(type) \
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((_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) \
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((_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) \
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(_Py_IntegralTypeMin(type) <= v && v <= _Py_IntegralTypeMax(type))
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//--- Implementation of the HAVE_PY_SET_53BIT_PRECISION macro -------------
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//--- defined in pyport.h -------------------------------------------------
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//
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// Give appropriate definitions for the following three macros:
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//
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// _Py_SET_53BIT_PRECISION_HEADER : any variable declarations needed to
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// use the two macros below.
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// _Py_SET_53BIT_PRECISION_START : store original FPU settings, and
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// set FPU to 53-bit precision/round-half-to-even
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// _Py_SET_53BIT_PRECISION_END : restore original FPU settings
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// Get and set x87 control word for gcc/x86
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#ifdef HAVE_GCC_ASM_FOR_X87
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// Functions defined in Python/pymath.c
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extern unsigned short _Py_get_387controlword(void);
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extern void _Py_set_387controlword(unsigned short);
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#define _Py_SET_53BIT_PRECISION_HEADER \
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unsigned short old_387controlword, new_387controlword
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#define _Py_SET_53BIT_PRECISION_START \
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do { \
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old_387controlword = _Py_get_387controlword(); \
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new_387controlword = (old_387controlword & ~0x0f00) | 0x0200; \
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if (new_387controlword != old_387controlword) { \
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_Py_set_387controlword(new_387controlword); \
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} \
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} while (0)
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#define _Py_SET_53BIT_PRECISION_END \
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do { \
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if (new_387controlword != old_387controlword) { \
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_Py_set_387controlword(old_387controlword); \
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} \
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} while (0)
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#endif
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// Get and set x87 control word for VisualStudio/x86.
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// x87 is not supported in 64-bit or ARM.
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#if defined(_MSC_VER) && !defined(_WIN64) && !defined(_M_ARM)
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#include <float.h> // __control87_2()
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#define _Py_SET_53BIT_PRECISION_HEADER \
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unsigned int old_387controlword, new_387controlword, out_387controlword
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// We use the __control87_2 function to set only the x87 control word.
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// The SSE control word is unaffected.
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#define _Py_SET_53BIT_PRECISION_START \
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do { \
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__control87_2(0, 0, &old_387controlword, NULL); \
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new_387controlword = \
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(old_387controlword & ~(_MCW_PC | _MCW_RC)) | (_PC_53 | _RC_NEAR); \
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if (new_387controlword != old_387controlword) { \
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__control87_2(new_387controlword, _MCW_PC | _MCW_RC, \
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&out_387controlword, NULL); \
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} \
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} while (0)
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#define _Py_SET_53BIT_PRECISION_END \
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do { \
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if (new_387controlword != old_387controlword) { \
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__control87_2(old_387controlword, _MCW_PC | _MCW_RC, \
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&out_387controlword, NULL); \
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} \
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} while (0)
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#endif
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#ifdef HAVE_GCC_ASM_FOR_MC68881
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#define _Py_SET_53BIT_PRECISION_HEADER \
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unsigned int old_fpcr, new_fpcr
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#define _Py_SET_53BIT_PRECISION_START \
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do { \
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__asm__ ("fmove.l %%fpcr,%0" : "=g" (old_fpcr)); \
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/* Set double precision / round to nearest. */ \
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new_fpcr = (old_fpcr & ~0xf0) | 0x80; \
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if (new_fpcr != old_fpcr) { \
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__asm__ volatile ("fmove.l %0,%%fpcr" : : "g" (new_fpcr));\
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} \
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} while (0)
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#define _Py_SET_53BIT_PRECISION_END \
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do { \
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if (new_fpcr != old_fpcr) { \
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__asm__ volatile ("fmove.l %0,%%fpcr" : : "g" (old_fpcr)); \
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} \
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} while (0)
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#endif
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// Default definitions are empty
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#ifndef _Py_SET_53BIT_PRECISION_HEADER
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# define _Py_SET_53BIT_PRECISION_HEADER
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# define _Py_SET_53BIT_PRECISION_START
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# define _Py_SET_53BIT_PRECISION_END
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#endif
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#ifdef __cplusplus
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}
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#endif
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#endif /* !Py_INTERNAL_PYMATH_H */
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