cosmopolitan/libc/math/ceill.c

35 lines
754 B
C

#include "libc/math/libm.h"
#if LDBL_MANT_DIG == 53 && LDBL_MAX_EXP == 1024
long double ceill(long double x)
{
return ceil(x);
}
#elif (LDBL_MANT_DIG == 64 || LDBL_MANT_DIG == 113) && LDBL_MAX_EXP == 16384
static const long double toint = 1/LDBL_EPSILON;
long double ceill(long double x)
{
union ldshape u = {x};
int e = u.i.se & 0x7fff;
long double y;
if (e >= 0x3fff+LDBL_MANT_DIG-1 || x == 0)
return x;
/* y = int(x) - x, where int(x) is an integer neighbor of x */
if (u.i.se >> 15)
y = x - toint + toint - x;
else
y = x + toint - toint - x;
/* special case because of non-nearest rounding modes */
if (e <= 0x3fff-1) {
FORCE_EVAL(y);
return u.i.se >> 15 ? -0.0 : 1;
}
if (y < 0)
return x + y + 1;
return x + y;
}
#endif