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Improve clog, clog10 handling of values with real or imaginary part 1 (bug 13629).

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This commit is contained in:
Joseph Myers
2012-07-26 11:31:35 +00:00
parent 3129cfc6ec
commit da865e95bc
10 changed files with 318 additions and 54 deletions
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36
math/s_clog10.c
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@ -44,21 +44,21 @@ __clog10 (__complex__ double x)
{
/* Neither real nor imaginary part is NaN. */
double absx = fabs (__real__ x), absy = fabs (__imag__ x);
double d;
int scale = 0;
if (absx < absy)
{
double t = absx;
absx = absy;
absy = t;
}
if (absx > DBL_MAX / 2.0)
{
scale = -1;
absx = __scalbn (absx, scale);
absy = (absy >= DBL_MIN * 2.0 ? __scalbn (absy, scale) : 0.0);
}
else if (absy > DBL_MAX / 2.0)
{
scale = -1;
absx = (absx >= DBL_MIN * 2.0 ? __scalbn (absx, scale) : 0.0);
absy = __scalbn (absy, scale);
}
else if (absx < DBL_MIN && absy < DBL_MIN)
{
scale = DBL_MANT_DIG;
@ -66,9 +66,27 @@ __clog10 (__complex__ double x)
absy = __scalbn (absy, scale);
}
d = __ieee754_hypot (absx, absy);
if (absx == 1.0 && scale == 0)
{
double absy2 = absy * absy;
if (absy2 <= DBL_MIN * 2.0 * M_LN10)
{
#if __FLT_EVAL_METHOD__ == 0
__real__ result = (absy2 / 2.0 - absy2 * absy2 / 4.0) * M_LOG10E;
#else
volatile double force_underflow = absy2 * absy2 / 4.0;
__real__ result = (absy2 / 2.0 - force_underflow) * M_LOG10E;
#endif
}
else
__real__ result = __log1p (absy2) * (M_LOG10E / 2.0);
}
else
{
double d = __ieee754_hypot (absx, absy);
__real__ result = __ieee754_log10 (d) - scale * M_LOG10_2;
}
__real__ result = __ieee754_log10 (d) - scale * M_LOG10_2;
__imag__ result = M_LOG10E * __ieee754_atan2 (__imag__ x, __real__ x);
}
else