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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_clogf.c
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@ -41,21 +41,21 @@ __clogf (__complex__ float x)
{
/* Neither real nor imaginary part is NaN. */
float absx = fabsf (__real__ x), absy = fabsf (__imag__ x);
float d;
int scale = 0;
if (absx < absy)
{
float t = absx;
absx = absy;
absy = t;
}
if (absx > FLT_MAX / 2.0f)
{
scale = -1;
absx = __scalbnf (absx, scale);
absy = (absy >= FLT_MIN * 2.0f ? __scalbnf (absy, scale) : 0.0f);
}
else if (absy > FLT_MAX / 2.0f)
{
scale = -1;
absx = (absx >= FLT_MIN * 2.0f ? __scalbnf (absx, scale) : 0.0f);
absy = __scalbnf (absy, scale);
}
else if (absx < FLT_MIN && absy < FLT_MIN)
{
scale = FLT_MANT_DIG;
@ -63,9 +63,27 @@ __clogf (__complex__ float x)
absy = __scalbnf (absy, scale);
}
d = __ieee754_hypotf (absx, absy);
if (absx == 1.0f && scale == 0)
{
float absy2 = absy * absy;
if (absy2 <= FLT_MIN * 2.0f)
{
#if __FLT_EVAL_METHOD__ == 0
__real__ result = absy2 / 2.0f - absy2 * absy2 / 4.0f;
#else
volatile float force_underflow = absy2 * absy2 / 4.0f;
__real__ result = absy2 / 2.0f - force_underflow;
#endif
}
else
__real__ result = __log1pf (absy2) / 2.0f;
}
else
{
float d = __ieee754_hypotf (absx, absy);
__real__ result = __ieee754_logf (d) - scale * (float) M_LN2;
}
__real__ result = __ieee754_logf (d) - scale * (float) M_LN2;
__imag__ result = __ieee754_atan2f (__imag__ x, __real__ x);
}
else