Re: Making Lemonade (Floating-point format changes)

John Savard wrote:

On Sun, 12 May 2024 13:46:28 -0000 (UTC), Thomas Koenig
<tkoenig@netcologne.de> wrote:

John Savard <quadibloc@servername.invalid> schrieb:
>

I have instead defined a 256-bit format for floats which does not have
a hidden first bit, which looks like the old temporary reals, except
that the exponent field is one bit wider.

>
Why not the IEEE binary256 (interchange) format?
>
https://en.wikipedia.org/wiki/Octuple-precision_floating-point_format

Oh, drat. I had not realized that they had also defined this.

Now that means I need to make the exponent field  in my internal
format larger, define a 512-bit floating point number which is in the
internal format, so that it can be unnormalized, and a 1024-bit
doubled-up float... instead of what I just did!

The enlarged exponent field won't make the internal form of the
128-bit float go over 160 bits, so register allocation for th at won't
change... but now I will have to figure out a scheme of register
allocation applicable to the 256-bit floats!

I am not amused.

Question:: why are you all so gung-ho on having a format without a hidden bit.
It is trivially easy to reconstruct::
     h = expon != 0;
Taking little time of even gates; and is something you HAVE to do anyway.

John Savard