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From: Stefan Slapeta (stefan_at_[hidden])
Date: 2006-03-03 05:10:02

Beman Dawes wrote:

> I assume you meant "the story *isn't* over here":-)

Anyway ... :-)

> It has been quite a while, but IIRC the three proposed types are also
> supposed to be useful for decimal integers. To emphasize that,
> "floating-point" was removed from the name of the proposal.
> Perhaps Robert can clarify.

They are for sure. A decimal with a zero scale is an integer.

>>(1) an arbitrary length integer type
>>(2) an arbitrary length decimal floating point type, which is a
>> combination of (1) with an integer-like scale so that
>> decimal_value = large_integer_value / 10 ^ scale
>>(3) three specializations of (2) to provide the IEEE and TR2
>> conforming interface (32, 64, 128 digits)
> "The best is the enemy of the good," as Voltaire said.

yes, and "multa petentibus multa desunt" ;-)

> We don't have (1) or (2) for binary arithmetic yet. How is decimal special
> in that regard?

Why would we need that for binary arithmetic?

> It might be possible to break the job down into:
> (A) A core decimal arithmetic engine (presumably tailorable to different
> lengths, and replicable by hardware if chip companies do start providing
> hardware engines.)
> (B) Public interfaces to the core engine.
> (C) A test suite for the core engine, concentrating on arithmetic
> correctness.
> (D) A test suite for the public interfaces, concentrating on interface
> correctness.
> If you make some progress on (A), perhaps others might volunteer to tackle
> the other parts.

I'll see what I can do, but it's a large job. I'm off now for 4 weeks
and I'll create something to start with afterwards. And we should also
take the discussions during the boost decimal review into account.


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