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Move handling of subnormals into FutureFeatures. #271

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Oct 26, 2015
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Move handling of subnormals into FutureFeatures. #271

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2 changes: 0 additions & 2 deletions AstSemantics.md
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Expand Up @@ -401,8 +401,6 @@ Floating point arithmetic follows the IEEE-754 standard, except that:
- WebAssembly uses the round-to-nearest ties-to-even rounding attribute, except
where otherwise specified. Non-default directed rounding attributes are not
supported.
- The strategy for gradual underflow (subnormals) is
[under discussion](https://github.com/WebAssembly/design/issues/148).

In the future, these limitations may be lifted, enabling
[full IEEE-754 support](FutureFeatures.md#full-ieee-754-conformance).
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8 changes: 8 additions & 0 deletions FutureFeatures.md
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Expand Up @@ -337,6 +337,14 @@ enabled only from developer tools, that would enable traps on selected floating
point exceptions, however care should be taken, since not all floating point
exceptions indicate bugs.

## Flushing Subnormal Values to Zero

Many popular CPUs have significant stalls when processing subnormal values,
and support modes where subnormal values are flushed to zero which avoid
these stalls. And, ARMv7 NEON has no support for subnormal values and always
flushes them. A mode where floating point computations have subnormals flushed
to zero in WebAssembly would address these two issues.

## Integer Overflow Detection

There are two different use cases here, one where the application wishes to
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