Sorry to be asking so many questions, but it's holiday time for me so I'm doing a lot of work in fasm (same project as last time still).

Moving on from lexical analysis in my programming language (which is going well btw) I am now implementing the variant type. I've written most of the structures and a few of the basic functions for casting etc. (when it's done it will practically be a library for dynamic typing in asm ) But I have a problem with floats:

I originally said in my plan for the language that I'd have three types of ints: 32, 64 and 128 bit and also 3 types of float (single, double and quad), but I've now found out that the fpu registers only go up to extended precision (80 bit). I was always going by the IEEE standard (forgotten the number now) that specified those three sizes, so it was a bit of a surprise when I found that the registers don't go there.

The main thing is... How do I get around it? I could always go back and change it to extended precision, but I'd rather support quad so I can say its going by the standard, and the extra accuracy would be good (the language is designed for maths mostly). But I've struggled enough with trying to work with single precision floats converting to strings and have no intention of making life any harder than it is for me. Any suggestions?

I suppose another question would be why? why do the registers only go up to 80bit floats and what about other OS'??

I promise no questions till next week after this

Mat

I think you will find that there are no commercial CPUs that support quad precision natively. Your only choice is to roll your own quad precision engine. Yes. Don't bother with quad precision unless you really have a need for it. Usually if someone needs really high precision (greater than double) then they also need to go much further than quad (i.e. an arbitrary precision requirement) so the quad precision is often not useful.

So why is it in the standard then? Grrrr....

I guess I'll be going back to just extended precision then. Makes much more sense that way (writing my own engine is not a prospect I look forward to, the registers make no sense as it is).

It is much easier to write a standard than it is to actually implement it.

BTW: IEEE754 is the number you are thinking of.