Re: Early-2014 Macbook Air and Linux Mint Cinnamon
Charlie Gibbs <[email protected]>
| Newsgroups | comp.sys.mac.vintage,comp.os.linux.misc |
|---|---|
| Message-ID | <ZE%[email protected]> |
On 2026-06-24, John Ames <[email protected]> wrote: > On Wed, 24 Jun 2026 19:42:20 GMT > Charlie Gibbs <[email protected]> wrote: > >> I figured that if they were going to do that, they might as well go >> whole hog and have constructs like LD PC,<addr> for a jump, and LD >> A,@<portnum> for input (LD @<portnum>,A for output, of course). > > MOV [operand], PC is actually a valid if non-conventional form of jump > on the PDP-11; the primary difference is that it sets the flags based > on the value of the target address. And, of course, it has memory- > mapped I/O, so MOV Rn, [port]/MOV [port], Rn is indeed how it's done ;) I remember being dazzled by the PDP-11's machine code. Making PC and SP just another two registers allowed all sorts of neat tricks, such as enabling programmers to write threaded code that the hardware could interpret as a byproduct of the architecture, not by convoluted tricks. -- /~\ Charlie Gibbs | No artificial \ / <[email protected]> | intelligence was X I'm really at ac.dekanfrus | used in the creation / \ if you read it the right way. | of this post.