[Bug ports/15492] New: ARM fesetenv doesn't preserve RunFast (reserved bits out of date)

[Bug ports/15492] New: ARM fesetenv doesn't preserve RunFast (reserved bits out of date)

[adam at spicenitz dot org]

http://sourceware.org/bugzilla/show_bug.cgi?id=15492

             Bug #: 15492
           Summary: ARM fesetenv doesn't preserve RunFast (reserved bits
                    out of date)
           Product: glibc
           Version: unspecified
            Status: NEW
          Severity: normal
          Priority: P2
         Component: ports
        AssignedTo: unassigned@sourceware.org
        ReportedBy: adam@spicenitz.org
                CC: carlos@redhat.com, roland@gnu.org
    Classification: Unclassified


_FPU_RESERVED in ports/sysdeps/arm/fpu_control.h is out of date. It improperly
masks bits that are now valid, including the Default NaN bit. This means
"RunFast" mode (where bits 24 and 25 are set) does not work across fesetenv.


Here is a more recent list of this bits:
http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.ddi0438h/CDEFCBDC.html

Given this new documentation, perhaps _FPU_RESERVED should now read as 0x8FF60.

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[Bug ports/15492] ARM fesetenv doesn't preserve RunFast (reserved bits out of date)

[joseph at codesourcery dot com]

http://sourceware.org/bugzilla/show_bug.cgi?id=15492

--- Comment #1 from joseph at codesourcery dot com <joseph at codesourcery dot com> 2013-05-20 12:12:32 UTC ---
On Mon, 20 May 2013, adam at spicenitz dot org wrote:

> http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.ddi0438h/CDEFCBDC.html
> 
> Given this new documentation, perhaps _FPU_RESERVED should now read as 0x8FF60.

You're looking at documentation for one particular processor, which lists 
as reserved bits that on other processors aren't reserved (e.g. trap 
enable bits).  DDI0406C suggests the correct reserved bits are 0x86060.

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[Bug ports/15492] ARM fesetenv doesn't preserve RunFast (reserved bits out of date)

[adam at spicenitz dot org]

http://sourceware.org/bugzilla/show_bug.cgi?id=15492

--- Comment #2 from Adam Goode <adam at spicenitz dot org> 2013-05-20 14:23:53 UTC ---
Yes, 0x86060 looks right.

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[Bug ports/15492] ARM fesetenv doesn't preserve RunFast (reserved bits out of date)

[jsm28 at gcc dot gnu.org]

http://sourceware.org/bugzilla/show_bug.cgi?id=15492

Joseph Myers <jsm28 at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|---                         |FIXED

--- Comment #3 from Joseph Myers <jsm28 at gcc dot gnu.org> ---
Fixed for 2.18 by:

commit c69f6af9e5a03620c253e75fd925d38adaa3c039
Author: Joseph Myers <joseph@codesourcery.com>
Date:   Fri Jun 14 21:19:35 2013 +0000

    Update ARM _FPU_RESERVED value.

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[Bug ports/15492] ARM fesetenv doesn't preserve RunFast (reserved bits out of date)

[fweimer at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=15492

Florian Weimer <fweimer at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
              Flags|                            |security-

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