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| author | Adhemerval Zanella <azanella@linux.vnet.ibm.com> | 2012-05-10 15:11:55 -0500 |
|---|---|---|
| committer | Ryan S. Arnold <rsa@linux.vnet.ibm.com> | 2012-05-10 15:11:55 -0500 |
| commit | 89c9aa491a7cee97bf78a29cddbf0a25c902a671 (patch) | |
| tree | a03f7f7a4864421a67c1f4ba3c4ad74090cc0e63 /math | |
| parent | 021db4be6f1f4189f66feee066a495d49e92b93e (diff) | |
| download | glibc-89c9aa491a7cee97bf78a29cddbf0a25c902a671.zip glibc-89c9aa491a7cee97bf78a29cddbf0a25c902a671.tar.gz glibc-89c9aa491a7cee97bf78a29cddbf0a25c902a671.tar.bz2 | |
Fix for logb/logbf/logbl (bugs 13954/13955/13956)
POSIX 2008 states that if the input for 'logb[f|l]' is a subnormal number
it should be treated as if it were normalized. This means the
implementation should calculate the log2 of the mantissa and add it to the
subnormal exponent (-126 for float and -1022 for double and IBM long
double). This patch takes care of that.
Diffstat (limited to 'math')
| -rw-r--r-- | math/libm-test.inc | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/math/libm-test.inc b/math/libm-test.inc index 542131d..5a38dbf 100644 --- a/math/libm-test.inc +++ b/math/libm-test.inc @@ -5376,6 +5376,22 @@ logb_test (void) TEST_f_f (logb, 1024, 10); TEST_f_f (logb, -2000, 10); + TEST_f_f (logb, 0x0.1p-127, -131); + TEST_f_f (logb, 0x0.01p-127, -135); + TEST_f_f (logb, 0x0.011p-127, -135); +#ifndef TEST_FLOAT + TEST_f_f (logb, 0x0.8p-1022, -1023); + TEST_f_f (logb, 0x0.1p-1022, -1026); + TEST_f_f (logb, 0x0.00111p-1022, -1034); + TEST_f_f (logb, 0x0.00001p-1022, -1042); + TEST_f_f (logb, 0x0.000011p-1022, -1042); + TEST_f_f (logb, 0x0.0000000000001p-1022, -1074); +#endif +#if defined TEST_LDOUBLE && LDBL_MIN_EXP - LDBL_MANT_DIG <= -16400 + TEST_f_f (logb, 0x1p-16400L, -16400); + TEST_f_f (logb, 0x.00000000001p-16382L, -16426); +#endif + END (logb); } |