On Wed, Nov 23, 2016 at 11:10:08AM +0530, Bharata B Rao wrote: > On Wed, Nov 23, 2016 at 03:01:18PM +1100, David Gibson wrote: > > On Tue, Nov 22, 2016 at 05:15:58PM +0530, Nikunj A Dadhania wrote: > > > From: Bharata B Rao <bhar...@linux.vnet.ibm.com> > > > > > > - xscmpodp & xscmpudp are missing flags reset. > > > - In xscmpodp, VXCC should be set only if VE is 0 for signalling NaN case > > > and VXCC should be set by explicitly checking for quiet NaN case. > > > - Comparison is being done only if the operands are not NaNs. However as > > > per ISA, it should be done even when operands are NaNs. > > > > For my interest, can you explain the difference between ordered and > > unordered comparisons? I looked at the ISA and mostly just became > > confused. > > >From another section of the same ISA doc, I see these description which > makes the distinction between ordered and unordered comparisions a bit > more clear. > > Unordered: > > "If either of the operands is a NaN, either quiet or signal- > ing, then CR field BF and the FPCC are set to reflect > unordered. If either of the operands is a Signaling NaN, > then VXSNAN is set." > > Ordered: > > "If either of the operands is a NaN, either quiet or signal- > ing, then CR field BF and the FPCC are set to reflect > unordered. If either of the operands is a Signaling NaN, > then VXSNAN is set and, if Invalid Operation is dis- > abled (VE=0), VXVC is set. If neither operand is a Sig- > naling NaN but at least one operand is a Quiet NaN, > then VXVC is set."
Ah, thanks. So it's basically just the setting of VXVC which differs.
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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