kaguya
56 lines
1004 B
C
56 lines
1004 B
C
#include <limits.h>
|
|
#include "libm.h"
|
|
|
|
#if LDBL_MANT_DIG == 53 && LDBL_MAX_EXP == 1024
|
|
int ilogbl(long double x)
|
|
{
|
|
return ilogb(x);
|
|
}
|
|
#elif LDBL_MANT_DIG == 64 && LDBL_MAX_EXP == 16384
|
|
int ilogbl(long double x)
|
|
{
|
|
#pragma STDC FENV_ACCESS ON
|
|
union ldshape u = {x};
|
|
uint64_t m = u.i.m;
|
|
int e = u.i.se & 0x7fff;
|
|
|
|
if (!e) {
|
|
if (m == 0) {
|
|
FORCE_EVAL(0/0.0f);
|
|
return FP_ILOGB0;
|
|
}
|
|
/* subnormal x */
|
|
for (e = -0x3fff+1; m>>63 == 0; e--, m<<=1);
|
|
return e;
|
|
}
|
|
if (e == 0x7fff) {
|
|
FORCE_EVAL(0/0.0f);
|
|
return m<<1 ? FP_ILOGBNAN : INT_MAX;
|
|
}
|
|
return e - 0x3fff;
|
|
}
|
|
#elif LDBL_MANT_DIG == 113 && LDBL_MAX_EXP == 16384
|
|
int ilogbl(long double x)
|
|
{
|
|
#pragma STDC FENV_ACCESS ON
|
|
union ldshape u = {x};
|
|
int e = u.i.se & 0x7fff;
|
|
|
|
if (!e) {
|
|
if (x == 0) {
|
|
FORCE_EVAL(0/0.0f);
|
|
return FP_ILOGB0;
|
|
}
|
|
/* subnormal x */
|
|
x *= 0x1p120;
|
|
return ilogbl(x) - 120;
|
|
}
|
|
if (e == 0x7fff) {
|
|
FORCE_EVAL(0/0.0f);
|
|
u.i.se = 0;
|
|
return u.f ? FP_ILOGBNAN : INT_MAX;
|
|
}
|
|
return e - 0x3fff;
|
|
}
|
|
#endif
|