Accuracy of floating point calculations

[Robert M. Münch]

On 2019-10-29 17:43:47 +0000, H. S. Teoh said:

> On Tue, Oct 29, 2019 at 04:54:23PM +0000, ixid via Digitalmars-d-learn wrote:
>> On Tuesday, 29 October 2019 at 16:11:45 UTC, Daniel Kozak wrote:
>>> On Tue, Oct 29, 2019 at 5:09 PM Daniel Kozak <kozzi11 at gmail.com> wrote:
>>> 
>>> AFAIK dmd use real for floating point operations instead of double
>> 
>> Given x87 is deprecated and has been recommended against since 2003 at
>> the latest it's hard to understand why this could be seen as a good
>> idea.
> 
> Walter talked about this recently as one of the "misses" in D (one of
> the things he predicted wrongly when he designed it).

Why should the real type be a wrong decision? Maybe the code generation 
should be optimized if all terms are double to avoid x87 but overall 
more precision is better for some use-cases.

I'm very happpy it exists, and x87 too because our app really needs 
this extended precision. I'm not sure what we would do if we only had 
doubles.

I'm not aware of any 128 bit real implementations done using SIMD 
instructions which get good speed. Anyone?

-- 
Robert M. Münch
http://www.saphirion.com
smarter | better | faster