cosmopolitan/libc/math/roundl.c

38 lines
669 B
C

#include "libc/math/libm.h"
#if LDBL_MANT_DIG == 53 && LDBL_MAX_EXP == 1024
long double roundl(long double x)
{
return round(x);
}
#elif (LDBL_MANT_DIG == 64 || LDBL_MANT_DIG == 113) && LDBL_MAX_EXP == 16384
static const long double toint = 1/LDBL_EPSILON;
long double roundl(long double x)
{
union ldshape u = {x};
int e = u.i.se & 0x7fff;
long double y;
if (e >= 0x3fff+LDBL_MANT_DIG-1)
return x;
if (u.i.se >> 15)
x = -x;
if (e < 0x3fff-1) {
FORCE_EVAL(x + toint);
return 0*u.f;
}
y = x + toint - toint - x;
if (y > 0.5)
y = y + x - 1;
else if (y <= -0.5)
y = y + x + 1;
else
y = y + x;
if (u.i.se >> 15)
y = -y;
return y;
}
#endif