long double
__truncl (long double x)
{
double xh, xl, hi, lo;
ldbl_unpack (x, &xh, &xl);
/* Return Inf, Nan, +/-0 unchanged. */
if (__builtin_expect (xh != 0.0
&& __builtin_isless (__builtin_fabs (xh),
__builtin_inf ()), 1))
{
double orig_xh;
/* Long double arithmetic, including the canonicalisation below,
only works in round-to-nearest mode. */
/* Convert the high double to integer. */
orig_xh = xh;
hi = ldbl_nearbyint (xh);
/* Subtract integral high part from the value. */
xh -= hi;
ldbl_canonicalize (&xh, &xl);
/* Now convert the low double, adjusted for any remainder from the
high double. */
lo = ldbl_nearbyint (xh);
/* Adjust the result when the remainder is non-zero. nearbyint
rounds values to the nearest integer, and values halfway
between integers to the nearest even integer. floorl must
round towards -Inf. */
xh -= lo;
ldbl_canonicalize (&xh, &xl);
if (orig_xh < 0.0)
{
if (xh > 0.0 || (xh == 0.0 && xl > 0.0))
lo += 1.0;
}
else
{
if (xh < 0.0 || (xh == 0.0 && xl < 0.0))
lo -= 1.0;
}
/* Ensure the final value is canonical. In certain cases,
rounding causes hi,lo calculated so far to be non-canonical. */
xh = hi;
xl = lo;
ldbl_canonicalize (&xh, &xl);
/* Ensure we return -0 rather than +0 when appropriate. */
if (orig_xh < 0.0)
xh = -__builtin_fabs (xh);
}
return ldbl_pack (xh, xl);
}
long double
__roundl (long double x)
{
double xh, xl, hi, lo;
ldbl_unpack (x, &xh, &xl);
/* Return Inf, Nan, +/-0 unchanged. */
if (__builtin_expect (xh != 0.0
&& __builtin_isless (__builtin_fabs (xh),
__builtin_inf ()), 1))
{
double orig_xh;
/* Long double arithmetic, including the canonicalisation below,
only works in round-to-nearest mode. */
/* Convert the high double to integer. */
orig_xh = xh;
hi = ldbl_nearbyint (xh);
/* Subtract integral high part from the value. */
xh -= hi;
ldbl_canonicalize (&xh, &xl);
/* Now convert the low double, adjusted for any remainder from the
high double. */
lo = ldbl_nearbyint (xh);
/* Adjust the result when the remainder is exactly 0.5. nearbyint
rounds values halfway between integers to the nearest even
integer. roundl must round away from zero.
Also correct cases where nearbyint returns an incorrect value
for LO. */
xh -= lo;
ldbl_canonicalize (&xh, &xl);
if (xh == 0.5)
{
if (xl > 0.0 || (xl == 0.0 && orig_xh > 0.0))
lo += 1.0;
}
else if (-xh == 0.5)
{
if (xl < 0.0 || (xl == 0.0 && orig_xh < 0.0))
lo -= 1.0;
}
/* Ensure the final value is canonical. In certain cases,
rounding causes hi,lo calculated so far to be non-canonical. */
xh = hi;
xl = lo;
ldbl_canonicalize (&xh, &xl);
}
return ldbl_pack (xh, xl);
}
long double
__rintl (long double x)
{
double xh, xl, hi, lo;
ldbl_unpack (x, &xh, &xl);
/* Return Inf, Nan, +/-0 unchanged. */
if (__builtin_expect (xh != 0.0
&& __builtin_isless (__builtin_fabs (xh),
__builtin_inf ()), 1))
{
double orig_xh;
int save_round = fegetround ();
/* Long double arithmetic, including the canonicalisation below,
only works in round-to-nearest mode. */
fesetround (FE_TONEAREST);
/* Convert the high double to integer. */
orig_xh = xh;
hi = ldbl_nearbyint (xh);
/* Subtract integral high part from the value. If the low double
happens to be exactly 0.5 or -0.5, you might think that this
subtraction could result in an incorrect conversion. For
instance, subtracting an odd number would cause this function
to round in the wrong direction. However, if we have a
canonical long double with the low double 0.5 or -0.5, then the
high double must be even. */
xh -= hi;
ldbl_canonicalize (&xh, &xl);
/* Now convert the low double, adjusted for any remainder from the
high double. */
lo = ldbl_nearbyint (xh);
xh -= lo;
ldbl_canonicalize (&xh, &xl);
switch (save_round)
{
case FE_TONEAREST:
if (xl > 0.0 && xh == 0.5)
lo += 1.0;
else if (xl < 0.0 && -xh == 0.5)
lo -= 1.0;
break;
case FE_TOWARDZERO:
if (orig_xh < 0.0)
goto do_up;
/* Fall thru */
case FE_DOWNWARD:
if (xh < 0.0 || (xh == 0.0 && xl < 0.0))
lo -= 1.0;
break;
case FE_UPWARD:
do_up:
if (xh > 0.0 || (xh == 0.0 && xl > 0.0))
lo += 1.0;
break;
}
/* Ensure the final value is canonical. In certain cases,
rounding causes hi,lo calculated so far to be non-canonical. */
xh = hi;
xl = lo;
ldbl_canonicalize (&xh, &xl);
/* Ensure we return -0 rather than +0 when appropriate. */
if (orig_xh < 0.0)
xh = -__builtin_fabs (xh);
fesetround (save_round);
}
return ldbl_pack (xh, xl);
}
