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| author | Joseph Myers <joseph@codesourcery.com> | 2015-04-10 20:45:30 +0000 |
|---|---|---|
| committer | Joseph Myers <joseph@codesourcery.com> | 2015-04-10 20:45:30 +0000 |
| commit | 5556d30caee170384553d2ae3247ec77a66b9ae8 (patch) | |
| tree | f17624c702ee8f1304651ebe95145205f294273d /ChangeLog | |
| parent | b3c66c534f8a9dbee44aa4983814fc52008f0323 (diff) | |
| download | glibc-5556d30caee170384553d2ae3247ec77a66b9ae8.tar.gz glibc-5556d30caee170384553d2ae3247ec77a66b9ae8.tar.xz glibc-5556d30caee170384553d2ae3247ec77a66b9ae8.zip | |
Fix strtof decimal rounding close to half least subnormal (bug 18247).
Bug 18247 is an off-by-one error in strtof's determination of a decimal exponent such that any value with that decimal exponent is at most half the least subnormal and so the appropriate underflowing value for the rounding mode can be determined with no multiple-precision computations. (Whether the value is in fact safe despite the off-by-one depends on the floating-point format in question. It's wrong for float and for m68k ldbl-96 but not for other supported formats.) This patch corrects the computation of the exponent in question to be safe in general, adding a comment explaining the new computation. Tested for x86_64. [BZ #18247] * stdlib/strtod_l.c (____STRTOF_INTERNAL): Decrease minimum decimal exponent by 1. * stdlib/tst-strtod-round-data: Add more tests. * stdlib/tst-strtod-round.c (tests): Regenerated.
Diffstat (limited to 'ChangeLog')
| -rw-r--r-- | ChangeLog | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/ChangeLog b/ChangeLog index 1456211390..def3b516bf 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,11 @@ +2015-04-10 Joseph Myers <joseph@codesourcery.com> + + [BZ #18247] + * stdlib/strtod_l.c (____STRTOF_INTERNAL): Decrease minimum + decimal exponent by 1. + * stdlib/tst-strtod-round-data: Add more tests. + * stdlib/tst-strtod-round.c (tests): Regenerated. + 2015-04-09 Joseph Myers <joseph@codesourcery.com> * math/auto-libm-test-in: Add more tests of clog and clog10. |