Bug 166463 - remquo[f] may return wrong sign in quo part and incorrect rem part on denormals
Summary: remquo[f] may return wrong sign in quo part and incorrect rem part on denormals
Status: Closed FIXED
Alias: None
Product: Base System
Classification: Unclassified
Component: standards (show other bugs)
Version: Unspecified
Hardware: Any Any
: Normal Affects Only Me
Assignee: David Schultz
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2012-03-28 13:40 UTC by Ilya Burylov
Modified: 2012-04-21 08:02 UTC (History)
0 users

See Also:

Attachments
file.diff (1.42 KB, patch)
2012-03-28 13:40 UTC, Ilya Burylov 		no flags Details | Diff
View All Add an attachment (proposed patch, testcase, etc.)

Note You need to log in before you can comment on or make changes to this bug.
Description Ilya Burylov 2012-03-28 13:40:09 UTC 
Currently we will get the wrong result as follows:

remquof(0x7bb33336, 0x63000000) = -671088640, 0x00000000 /* wrong sign in quo */
remquo(0xbff0000000000003, 0x3ff0000000000003) = 1, 0x8000000000000000 /* wrong sign in quo */
remquo(0x9120000000000001, 0x0000000000000005) = -1288490188, 0x0000000000000004 /* wrong quo and rem parts */

while [an example of] correct one should be:

remquof(0x7bb33336, 0x63000000) = 1476395008, 0x00000000
remquo(0xbff0000000000003, 0x3ff0000000000003) = -1, 0x8000000000000000
remquo(0x9120000000000001, 0x0000000000000005) = -1288490189, 0x0000000000000001

That does not fit into description in C99 standard: e.g. "In
the object pointed to by quo they store a value whose sign is the sign of x/y"

Fix attached

Fix: Fix should be applied to 
\msun\src\s_remquo.c
\msun\src\s_remquof.c

Fix attached.

Patch attached with submission follows:
How-To-Repeat: Reproducible in description
Comment 1 David Schultz freebsd_committer freebsd_triage 2012-04-07 04:38:23 UTC 
Responsible Changed
From-To: freebsd-standards->das

This looks like the right fix.  I will look into it.
Comment 2 David Schultz freebsd_committer freebsd_triage 2012-04-07 05:00:10 UTC 
State Changed
From-To: open->patched

Thanks for the bug report and the patch!  I've applied it in r233973, 
which fixes remquol() as well.
Comment 3 David Schultz freebsd_committer freebsd_triage 2012-04-21 08:01:12 UTC 
State Changed
From-To: patched->closed

Merged to 7, 8, and 9-STABLE in revs 234533-234535.