On 5/15/2016 10:37 PM, Manu via Digitalmars-d wrote:
No, you'll give me 80bit _when I type "real"_. Otherwise, if I type
'double', you'll give me that. I don't understand how that can be
controversial.
Because, as I explained, that results in a 2x or more speed degradation (along
with the loss of accuracy).
I know you love the x87, but I'm pretty sure you're among a small
minority. Personally, I don't want a single line of code that goes
anywhere near the x87 to be emit in any binary I produce. It's a
deprecated old crappy piece of hardware, and transfers between x87 and
sse regs are slow.
I used to do numerics work professionally. Most of the troubles I had were
catastrophic loss of precision. Accumulated roundoff errors when doing numerical
integration or matrix inversion are major problems. 80 bits helps dramatically
with that.
It's also why I'd like to build a 128 soft fp emulator in dmd for all
compile time float operations.
And I did also realise the reason for your desire to implement 128bit
soft-float the same moment I realised this. The situation that
different DMD builds operate at different precisions internally (based
on the host arch) is a whole new level of astonishment.
Then you're probably also astonished at the links I posted to you on how g++ and
VC++ behave with FP.
