Re: PDD 4: Internal data types

[David Mitchell]

> The C structure that represents a bigint is:
> 
>    struct bigint {
>      void *num_buffer;
>      UV length;
>      IV exponent;
>      UV flags;
>    }
> 
[snip] 
> The C<num_buffer> pointer points to the buffer holding the actual
> number, C<length> is the length of the buffer, C<exponent> is the base
> 10 exponent for the number (so 2e4532 doesn't take up much space), and
> C<flags> are some flags for the bigint.

Err... what representation is enivsaged for bigints? I had assumed it
would be (length*8)-bit 2's complement, but the the later bit about
base-10 exponents and digits made me wonder if you were actually intending
a string (or BCD) represenation?

In either case, the PDD needs to make it clear. (And if the latter,
then permission to say "yuk!")

bignum perhaps also needs some clarification.

Dave.