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Copy pathpymath.c
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96 lines (84 loc) · 1.94 KB
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#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 */
#ifdef _Py_MEMORY_SANITIZER
__attribute__((no_sanitize_memory))
#endif
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 */
static const unsigned int BitLengthTable[32] = {
0, 1, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4,
5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5
};
unsigned int _Py_bit_length(unsigned long d) {
unsigned int d_bits = 0;
while (d >= 32) {
d_bits += 6;
d >>= 6;
}
d_bits += BitLengthTable[d];
return d_bits;
}