Re: is Vax addressing sane today

On 9/24/2024 10:57 AM, MitchAlsup1 wrote:

On Tue, 24 Sep 2024 17:06:27 +0000, Stephen Fuld wrote:
 

On 9/23/2024 11:02 PM, Terje Mathisen wrote:
>
snip
>

Maybe all add/sub/etc opcodes that are immediately followed by an INTO
could be fused into a single ADDO/SUBO/etc version that takes zero extra
cycles as long as the trap part isn't hit?

>
If you are going to do that, why not make it an optional prefix byte?
That way, no fusion needed, no extra cycles, yet the same amount of code
space.

 Realistically, what is the difference if INTO is a prefix
byte or a postfix byte ?

Of course, IANAHG, but my guess was that not having to do instruction fusion was worth something, and my suggestion has zero cost.  If this is wrong, then there is no difference.
--
  - Stephen Fuld
(e-mail address disguised to prevent spam)