Re: [Qemu-devel] [PATCH for-3.1 0/7] target/ppc fp cleanups

[David Gibson <david@gibson.dropbear.id.au>]

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On Tue, Jul 03, 2018 at 08:17:25AM -0700, Richard Henderson wrote:
> Beginning with John Arbuckle's fdiv test case, clean up some
> of the fp helpers.  As with fdiv, fre and fresqrt are missing
> divide-by-zero exceptions.
> 
> I've also noticed that load/store were using arithmetic conversions
> to/from float32.  These should be using the non-arithmetic algorithms
> listed in the manual.
> 
> Aside from cleaning up all of the rest of the helpers, I believe that
> the implementation of the single-precision operations are incorrect.
> They are currently implemented with the double-precision operation
> followed by a round-to-single.  This causes incorrect results via
> double rounding.  I believe better results could be had by using
> these non-arithmetic converters to produce float32 operands, use the
> proper float32 softfloat operations, and then convert back.
> 
> Anyway, all of this has been broken long enough that it'll need to
> wait til next devel cycle before anything further gets done.

Applied to ppc-for-3.1 (newly created).

-- 
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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