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Re: 64-bit ints and non-capable hardware

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Rhys Weatherley
October 22, 2002 17:08
Re: 64-bit ints and non-capable hardware
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Martin D Kealey wrote:

> I was wondering if anyone else followed the discussion in comp.std.c about
> integer types, prior to the adoption of the C99 standard? There was a
> substantial paper put out by Frank Farance, entitled "specification based
> extended integer range" or SBEIR for short; see

Very interesting proposal.  I wish they had adopted it.  Would
have saved me a lot of hassle with typedefs over the years. :-)

This kind of system works well in a statically compiled language
like C because the compiler can look at "signed int exact:32" and
say "Oh!  That's just int on this platform!" and then compile
away the distinction.

I'm not sure how well it would work in a dynamic environment like
Parrot, where the compiler doesn't necessarily know the final actual
type.  It is up to the runtime engine.  e.g. how would the engine
rearrange the code to do "signed int exact:64" with PMC's on 32-bit
platforms and I registers on 64-bit?  That way lies polymorphic
instruction sets and other CLI madness ...

Having said that, it might be nice to have a variant on BIGINT
that can be dynamically range-limited using dynamically-specified
rules.  Then 64-bit ints can be created as instances of RANGEBIGINT.



P.S. I suspect one reason why it was rejected was because some
programmer would ask for "signed int exact:23517" and expect it
to work on every compiler.  Implementing the intrinsics for
something like that is *hard*.

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