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From: "cvs-commit at gcc dot gnu.org" <sourceware-bugzilla@sourceware.org> To: glibc-bugs@sourceware.org Subject: [Bug math/17803] scalblnl differs from scabnl and ldexpl (with radix 2) Date: Mon, 12 Jan 2015 23:03:00 -0000 [thread overview] Message-ID: <bug-17803-131-JPffuPCzHY@http.sourceware.org/bugzilla/> (raw) In-Reply-To: <bug-17803-131@http.sourceware.org/bugzilla/> https://sourceware.org/bugzilla/show_bug.cgi?id=17803 --- Comment #2 from cvs-commit at gcc dot gnu.org <cvs-commit at gcc dot gnu.org> --- This is an automated email from the git hooks/post-receive script. It was generated because a ref change was pushed to the repository containing the project "GNU C Library master sources". The branch, master has been updated via 5a9e4c09a2601a8100ea9a1f7bc0360782cd1625 (commit) from 34e93d6c76b7a6eaf94697a172b958704fd33396 (commit) Those revisions listed above that are new to this repository have not appeared on any other notification email; so we list those revisions in full, below. - Log ----------------------------------------------------------------- https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=5a9e4c09a2601a8100ea9a1f7bc0360782cd1625 commit 5a9e4c09a2601a8100ea9a1f7bc0360782cd1625 Author: Joseph Myers <joseph@codesourcery.com> Date: Mon Jan 12 23:02:14 2015 +0000 Fix ldbl-96 scalblnl underflowing results (bug 17803). The ldbl-96 implementation of scalblnl (used for x86_64 and ia64) uses a condition k <= -63 to determine when a standard underflowing result tiny*__copysignl(tiny,x) should be returned. However, that condition corresponds to values with exponent -16446 or less, and in the case of -16446, the correct result for round-to-nearest depends on whether the value is exactly 0x1p-16446 (half the least subnormal) or more than that. This patch fixes the bug by changing the condition to k <= -64 and accordingly adjusting the exponent by 64 not 63 when converting to a normal value. Tested for x86_64. [BZ #17803] * sysdeps/ieee754/ldbl-96/s_scalblnl.c (twom63): Rename to twom64. Adjust value to 0x1p-64L. (__scalblnl): Only return standard underflowing result for K <= -64 not K <= -63; adjust exponent for underflowing result by 64 not 63. * math/libm-test.inc (scalbn_test_data): Add more tests. (scalbln_test_data): Likewise. ----------------------------------------------------------------------- Summary of changes: ChangeLog | 9 ++++++++ NEWS | 2 +- math/libm-test.inc | 38 ++++++++++++++++++++++++++++++++++ sysdeps/ieee754/ldbl-96/s_scalblnl.c | 8 +++--- 4 files changed, 52 insertions(+), 5 deletions(-) -- You are receiving this mail because: You are on the CC list for the bug.
next prev parent reply other threads:[~2015-01-12 23:03 UTC|newest] Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top 2015-01-06 11:22 [Bug libc/17803] New: " walter.mascarenhas at gmail dot com 2015-01-06 11:23 ` [Bug libc/17803] " walter.mascarenhas at gmail dot com 2015-01-06 17:35 ` [Bug math/17803] " jsm28 at gcc dot gnu.org 2015-01-12 22:36 ` cvs-commit at gcc dot gnu.org 2015-01-12 23:03 ` cvs-commit at gcc dot gnu.org [this message] 2015-01-12 23:04 ` jsm28 at gcc dot gnu.org
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