#include "Python.h" | |
#ifdef X87_DOUBLE_ROUNDING | |
/* On x86 platforms using an x87 FPU, this function is called from the | |
Py_FORCE_DOUBLE macro (defined in pymath.h) to force a floating-point | |
number out of an 80-bit x87 FPU register and into a 64-bit memory location, | |
thus rounding from extended precision to double precision. */ | |
double _Py_force_double(double x) | |
{ | |
volatile double y; | |
y = x; | |
return y; | |
} | |
#endif | |
#ifdef HAVE_GCC_ASM_FOR_X87 | |
/* inline assembly for getting and setting the 387 FPU control word on | |
gcc/x86 */ | |
unsigned short _Py_get_387controlword(void) { | |
unsigned short cw; | |
__asm__ __volatile__ ("fnstcw %0" : "=m" (cw)); | |
return cw; | |
} | |
void _Py_set_387controlword(unsigned short cw) { | |
__asm__ __volatile__ ("fldcw %0" : : "m" (cw)); | |
} | |
#endif | |
#ifndef HAVE_HYPOT | |
double hypot(double x, double y) | |
{ | |
double yx; | |
x = fabs(x); | |
y = fabs(y); | |
if (x < y) { | |
double temp = x; | |
x = y; | |
y = temp; | |
} | |
if (x == 0.) | |
return 0.; | |
else { | |
yx = y/x; | |
return x*sqrt(1.+yx*yx); | |
} | |
} | |
#endif /* HAVE_HYPOT */ | |
#ifndef HAVE_COPYSIGN | |
double | |
copysign(double x, double y) | |
{ | |
/* use atan2 to distinguish -0. from 0. */ | |
if (y > 0. || (y == 0. && atan2(y, -1.) > 0.)) { | |
return fabs(x); | |
} else { | |
return -fabs(x); | |
} | |
} | |
#endif /* HAVE_COPYSIGN */ | |
#ifndef HAVE_ROUND | |
double | |
round(double x) | |
{ | |
double absx, y; | |
absx = fabs(x); | |
y = floor(absx); | |
if (absx - y >= 0.5) | |
y += 1.0; | |
return copysign(y, x); | |
} | |
#endif /* HAVE_ROUND */ |