32 lines
654 B
C
32 lines
654 B
C
|
#include "libm.h"
|
||
|
|
|
||
|
|
#if FLT_EVAL_METHOD==0 || FLT_EVAL_METHOD==1
|
||
|
|
#define EPS DBL_EPSILON
|
||
|
|
#elif FLT_EVAL_METHOD==2
|
||
|
|
#define EPS LDBL_EPSILON
|
||
|
|
#endif
|
||
|
|
static const double_t toint = 1/EPS;
|
||
|
|
|
||
|
|
double ceil(double x)
|
||
|
|
{
|
||
|
|
union {double f; uint64_t i;} u = {x};
|
||
|
|
int e = u.i >> 52 & 0x7ff;
|
||
|
|
double_t y;
|
||
|
|
|
||
|
|
if (e >= 0x3ff+52 || x == 0)
|
||
|
|
return x;
|
||
|
|
/* y = int(x) - x, where int(x) is an integer neighbor of x */
|
||
|
|
if (u.i >> 63)
|
||
|
|
y = x - toint + toint - x;
|
||
|
|
else
|
||
|
|
y = x + toint - toint - x;
|
||
|
|
/* special case because of non-nearest rounding modes */
|
||
|
|
if (e <= 0x3ff-1) {
|
||
|
|
FORCE_EVAL(y);
|
||
|
|
return u.i >> 63 ? -0.0 : 1;
|
||
|
|
}
|
||
|
|
if (y < 0)
|
||
|
|
return x + y + 1;
|
||
|
|
return x + y;
|
||
|
|
}
|