[cfp-interest 3508] Re: Rounding Direction Mode or Rounding Direction or Rounding Mode

[Vincent Lefevre]

On 2025-05-30 13:55:16 +1000, Damian McGuckin wrote:
> 
> These three terms pop up and I cannot pick the consistency.
> 
> Which is which?
> 
> I thought that the collective term was rounding modes.

IEEE 754-1985 was calling them "rounding modes". But for the
2008 revision, "mode" was changed to "attribute", AFAIK because
some readers incorrectly interpreted them as necessarily being
dynamic. And I suppose that "direction" was added because there
are other attributes related to rounding.

> Mind you, IEEE 754 uses another (related but with even more letters) and
> calls all of these by the name "rounding direction attributes":
> 
> 	round towards zero
> and
> 	round towards infinity
> and
> 	round towards -infinity
> and
> 	round to nearest ties towards WHATEVER

In 1985, they were called
  * round toward 0
  * round toward +INFINITY
  * round toward -INFINITY
  * round to nearest
(note: "toward" without a "s").

The new names since IEEE 754-2008 are
  * roundTowardZero
  * roundTowardPositive
  * roundTowardNegative
  * roundTiesToEven (and roundTiesToAway was added, mainly due to the
    introduction of decimal arithmetic, where it is preferred).

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