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| author | Joseph Myers <joseph@codesourcery.com> | 2012-07-31 14:21:19 +0000 |
|---|---|---|
| committer | Joseph Myers <joseph@codesourcery.com> | 2012-07-31 14:21:19 +0000 |
| commit | d0419dbfbd19cb01398d43895a679c0bcb961070 (patch) | |
| tree | d600a45e750c40eed4d2050bd2b3bba3c9e64309 /math/s_clog10l.c | |
| parent | 2bc1387273d2123398fc12133643ea2bc02a2cd1 (diff) | |
| download | glibc-d0419dbfbd19cb01398d43895a679c0bcb961070.tar.gz glibc-d0419dbfbd19cb01398d43895a679c0bcb961070.tar.xz glibc-d0419dbfbd19cb01398d43895a679c0bcb961070.zip | |
Improve clog, clog10 handling of values with real or imaginary part slightly above 1 (bug 13629).
Diffstat (limited to 'math/s_clog10l.c')
| -rw-r--r-- | math/s_clog10l.c | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/math/s_clog10l.c b/math/s_clog10l.c index 2a380f6f3b..d50f616578 100644 --- a/math/s_clog10l.c +++ b/math/s_clog10l.c @@ -22,6 +22,13 @@ #include <math_private.h> #include <float.h> +/* To avoid spurious underflows, use this definition to treat IBM long + double as approximating an IEEE-style format. */ +#if LDBL_MANT_DIG == 106 +# undef LDBL_EPSILON +# define LDBL_EPSILON 0x1p-106L +#endif + /* log_10 (2). */ #define M_LOG10_2l 0.3010299956639811952137388947244930267682L @@ -75,6 +82,13 @@ __clog10l (__complex__ long double x) else __real__ result = __log1pl (absy2) * (M_LOG10El / 2.0L); } + else if (absx > 1.0L && absx < 2.0L && absy < 1.0L && scale == 0) + { + long double d2m1 = (absx - 1.0L) * (absx + 1.0L); + if (absy >= LDBL_EPSILON) + d2m1 += absy * absy; + __real__ result = __log1pl (d2m1) * (M_LOG10El / 2.0L); + } else { long double d = __ieee754_hypotl (absx, absy); |