Subj : Re: RP2350 and Pico 2 - things missing
To   : James Harris
From : Lawrence D'Oliveiro
Date : Sat Aug 17 2024 07:22:40

On Thu, 15 Aug 2024 17:47:51 +0100, James Harris wrote:

> Of course, it could be possible to run into more PIO memory than 32
> words as long as the requisite jumps were back to the initial 32-word
> space but that would be awkward to use, and limiting.

Or, you could bring back the old PDP-8 trick, of having the jump address
be in the *current page*. That means the upper bits are taken from the
current program counter.

There was actually a separate mode bit that indicated whether the address
was in the current page or page 0. And another bit to indicate whether the
access was indirect (i.e. don’t take the contents of that address, take
the contents of the contents).

--- SoupGate-Win32 v1.05
 * Origin: Agency HUB, Dunedin - New Zealand | Fido<>Usenet Gateway (3:770/3)

.