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Re: Expanding roundeven (Was: Re: About GSOC.)
On Thu, 13 Jun 2019, Martin Jambor wrote:
> architecture supports it. (and if IIUC, the intent is to use the 0 mode
> from table 4-8 in
> https://software.intel.com/sites/default/files/managed/39/c5/325462-sdm-vol-1-2abcd-3abcd.pdf
> in instructions that take a rounding a mode to implement roundeven).
Note that the rounding mode argument to roundss / roundsd should end up as
8, not 0, so that the inexact exception is not raised. (8 here is the
existing ROUND_NO_EXC definition in GCC. A new definition will need
adding alongside ROUND_FLOOR, ROUND_CEIL and ROUND_TRUNC to correspond to
rounding to nearest with ties to even, evaluating to 0.)
--
Joseph S. Myers
joseph@codesourcery.com