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Re: [PATCH] S390: Do not set FE_INEXACT with feraiseexcept (FE_OWERFLOW|FE_UNDERFLOW).

On 08/18/2016 05:59 PM, Joseph Myers wrote:

On Thu, 18 Aug 2016, Stefan Liebler wrote:


Hi,

on s390 feraiseexcept (FE_OVERFLOW|FE_UNDERFLOW) sets FE_INEXACT, too.


Note that this is permitted by the standards (whereas implicitly setting
FE_INEXACT is not permitted for fesetexcept, or fesetexceptflag if it
wasn't set in the saved state).


Hi Joseph,
fesetexcept and fesetexceptflag are using the _FPU_SETCW macro to set the flags. They don't implicitly set FE_INEXACT.
For feraiseexcept I think if the z196-round-instruction is available with used toolchain then it should be used to avoid FE_INEXACT. Then it is the same behaviour as on intel. If it is not available feraiseexcept will use the add/div instructions as before with the FE_INEXACT flag/exception. And the additional _FPU_GETCW/SETCW usages are avoided. 

What's your suggestion for feraiseexcept?

Bye
Stefan
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