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  1. 18 Aug, 2007 9 commits
  3. 17 Aug, 2007 2 commits
    • David S. Miller's avatar
      [MATH-EMU]: Fix underflow exception reporting. · 40584961
      David S. Miller authored 
      The underflow exception cases were wrong.

This is one weird area of ieee1754 handling in that the underflow
behavior changes based upon whether underflow is enabled in the trap
enable mask of the FPU control register.  As a specific case the Sparc
V9 manual gives us the following description:

--------------------
If UFM = 0:     Underflow occurs if a nonzero result is tiny and a
                loss of accuracy occurs.  Tininess may be detected
                before or after rounding.  Loss of accuracy may be
                either a denormalization loss or an inexact result.

If UFM = 1:     Underflow occurs if a nonzero result is tiny.
                Tininess may be detected before or after rounding.
--------------------

What this amounts to in the packing case is if we go subnormal,
we set underflow if any of the following are true:

1) rounding sets inexact
2) we ended up rounding back up to normal (this is the case where
   we set the exponent to 1 and set the fraction to zero), this
   should set inexact too
3) underflow is set in FPU control register trap-enable mask

The initially discovered example was "DBL_MIN / 16.0" which
incorrectly generated an underflow.  It should not, unless underflow
is set in the trap-enable mask of the FPU csr.

Another example, "0x0.0000000000001p-1022 / 16.0", should signal both
inexact and underflow.  The cpu implementations and ieee1754
literature is very clear about this.  This is case #2 above.

However, if underflow is set in the trap enable mask, only underflow
should be set and reported as a trap.  That is handled properly by the
prioritization logic in

arch/sparc{,64}/math-emu/math.c:record_exception().

Based upon a report and test case from Jakub Jelinek.
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      40584961
    • Ilpo Järvinen's avatar
      [POWERPC] Fix invalid semicolon after if statement · 2b02d139
      Ilpo Järvinen authored 
      A similar fix to netfilter from Eric Dumazet inspired me to
look around a bit by using some grep/sed stuff as looking for
this kind of bugs seemed easy to automate.  This is one of them
I found where it looks like this semicolon is not valid.
Signed-off-by: default avatarIlpo Järvinen <ilpo.jarvinen@helsinki.fi>
Acked-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
      2b02d139
  5. 16 Aug, 2007 5 commits
  7. 15 Aug, 2007 24 commits
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