# Some Functions Computable with a Fused-mac

Abstract : The fused multiply accumulate instruction (fused-mac) that is available on some current processors such as the Power PC or the Itanium eases some calculations. We give examples of some floating-point functions (such as $\ulp(x)$ or $\mathrm{Nextafter}(x,y)$), or some useful tests, that are easily computable using a fused-mac. Then, we show that, with rounding to the nearest, the error of a fused-mac instruction is exactly representable as the sum of two floating-point numbers. We give an algorithm that computes that error.
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https://hal-lara.archives-ouvertes.fr/hal-02101859
Contributor : Colette Orange <>
Submitted on : Wednesday, April 17, 2019 - 9:08:18 AM
Last modification on : Sunday, May 19, 2019 - 1:20:43 AM

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RR2004-41.pdf
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• HAL Id : hal-02101859, version 1

### Citation

Sylvie Boldo, Jean-Michel Muller. Some Functions Computable with a Fused-mac. [Research Report] LIP RR-2004-41, Laboratoire de l'informatique du parallélisme. 2004, 2+10p. ⟨hal-02101859⟩

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