Fused multiply add?

[Jay Lemmon]

Any timeline/plan for adding fused-multiply-add to the API?  eg: http://en.wikipedia.org/wiki/FMA_instruction_set

Obviously emulating it properly in older SSE or even AVX 1 would be a nightmare (handling the rounding guarantees that a proper FMA gives you, I mean), but entirely ignoring that issue and just doing the multiply and add one after another is probably fine in many/most cases.  There's probably even a performance benefit to a single API call since you avoid reloading data.

[Marat Dukhan]

Fused-multiply add instructions are already used in Yeppp! on supported platforms. E.g. vector log and exp functions have implementations for both FMA4 (targeting Bulldozer) and FMA3 (targeting Haswell).

A multiply-add operation, with FMA-based implementation on capable platforms, will be supported in the next Yeppp! release. However, I can not provide a timeline for when it will be released.

Regards,

Marat

On Wed, Apr 16, 2014 at 8:01 PM, Jay Lemmon <num...@gmail.com> wrote:

Any timeline/plan for adding fused-multiply-add to the API?  eg: http://en.wikipedia.org/wiki/FMA_instruction_set

Obviously emulating it properly in older SSE or even AVX 1 would be a nightmare (handling the rounding guarantees that a proper FMA gives you, I mean), but entirely ignoring that issue and just doing the multiply and add one after another is probably fine in many/most cases.  There's probably even a performance benefit to a single API call since you avoid reloading data.

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