[Bug ports/10064] New: ARM fesetround doesn't work as expected with VFP present but unused

[Bug ports/10064] New: ARM fesetround doesn't work as expected with VFP present but unused

[adam at spicenitz dot org]

When using software floating point, fesetround should return error on all but
the default rounding mode. When VFP hardware happens to be present, fesetround
will program the VFP to the rounding mode, and not return error. Unfortunately,
software floating point rounding mode is not changed. This causes programs which
would otherwise detect the failure to change rounding mode to fail later in
subtle ways.

How to fix this? Is there a way to detect if an application is not using the
VFP? I see some ELF tags that might be relevant. Otherwise, could glibc
implement the aeabi floating point helper functions instead of gcc? Then, it
could choose to use the VFP when present in hardware, or use the assembly
version when there is no VFP.

-- 
           Summary: ARM fesetround doesn't work as expected with VFP present
                    but unused
           Product: glibc
           Version: unspecified
            Status: NEW
          Severity: normal
          Priority: P2
         Component: ports
        AssignedTo: roland at gnu dot org
        ReportedBy: adam at spicenitz dot org
                CC: glibc-bugs at sources dot redhat dot com
  GCC host triplet: armv5tel-redhat-linux-gnueabi


http://sourceware.org/bugzilla/show_bug.cgi?id=10064

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