[gambit-list] SRFI-56(Re: Reading binary files)

Christian Jaeger christian at pflanze.mine.nu
Thu Dec 20 13:21:00 EST 2007


Siegfried Gonzi wrote:
> I always thought there are two types for most of the 'modern languages' (e.g. Clean which I first learnt and  Scheme compilers): long integer, and double precision C type?

Maybe some partial answer:

Scheme systems implementing the full numeric tower (like Gambit) have 
bignums, "much better" than "long integer". But Gambit also supports 
various fixed-size number vectors, see the documentation.

Regarding floating point numbers, you should be aware that x86 
processors have 80-bit wide floating point numbers which are not 
standard; IEEE standardized 64-bit floating point numbers. The latter 
can be chosen by using the "double" type in C, but usually, compiled C 
code on PC's does internal calculations in the 80-bit types.

In contrast to this, AFAICT, Gambit always works with clean 64-bit 
numbers in it's flonum handling. Of course when using the FFI, C code 
usually uses the 80-bit numbers for intermediates.

(I haven't looked at the code you're referring to.)

Christian.



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