std.math performance (SSE vs. real)

[Russel Winder via Digitalmars-d]

Hopefully there are points here for pedantry and bloody mindedness…


On Sat, 2014-06-28 at 18:32 -0700, Walter Bright via Digitalmars-d
wrote:
[…]
> Keep in mind that D is a systems programming language, and that
implies you get 
> access to the hardware types.


On Sun, 2014-06-29 at 12:22 -0700, Walter Bright via Digitalmars-d
wrote:
[…].
> 
> That is not  true with D. D specifies that float and double are IEEE 754 types 
> which have specified size and behavior. D's real type is the largest the 
> underlying hardware will support.
> 
> D also specifies 'int' is 32 bits, 'long' is 64, and 'byte' is 8, 'short' is 16.


D gives access to the hardware types, and D defines the structure of all
those types. The only resolution is that D only works on that hardware
where the hardware types are the ones D defines. Thus D only works on a
subset of hardware, and can never be ported to hardware where the
hardware types differ from those defined by D.

So D float and double will not work on IBM 360 unless interpreted, and
real would be 128-bit (not IEEE)?

The D real type definitely suffers the C/C++ float and double problem!

I guess we just hope that all future hardware is IEEE754 compliant.


(This is both a trivial issue and a brick wall issue so let's keep thing
humour-ful!)
-- 
Russel.
=============================================================================
Dr Russel Winder      t: +44 20 7585 2200   voip: sip:russel.winder at ekiga.net
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