[m-dev.] argument packing

[Julien Fischer]

On Wed, 16 May 2018, Zoltan Somogyi wrote:

>> PS. YesLogic don't have any code using sub-word-sized integers yet.
>
> I intend to add some to the compiler. Specificially, I mean to use uint8s
> to represent both primary tags, and the number of bits in arg_pos_widths
> (and maybe in other contexts) where the number of bits is guaranteed to be
> in the range 0 to 64. This should give us some dogfood.
>
> By the way, Julien: You added arithmetic and logical operations on
> sub-word-sized integers to builtin_ops.m. Did you intend to add any of
> the conversion operations, such as int8 to int? Did you reject it as requiring
> expansion of the expansion of the existing builtin_op framework?

No, it was simply something that didn't occur to me as being necessary
at the time I added the others.

> For work on ptags and num_bits, it would be nice if at least the
> unchecked conversions (casts) could be builtin.

I have no objections.

Julien.