On 2013-01-11 04:46, Dave McGuire wrote:
On 01/10/2013 10:44 PM, Johnny Billquist wrote:PDP-11 CPU internal registers appear in I/O address space, with some exceptions: the general registers are not visible there except in the 11/10. (They have listed addresses, but those only work from the console, not from programs, with that one exception.) And yes, on the PDP-10, the general registers live at memory addresses 0 to 017.It's more than the 11/10, but it's also really weird, and I don't remember if it's front panel only, but you might be right on that one.11/05 too, but that's the same machine. I'm pretty sure that's the only PDP-11 CPU that does that.
I have a clear memory of playing with this, and I don't recall ever playing much on an 11/10 or 11/05. I'm pretty sure it was on the 11/70...
Ah, yes. Checking the processor handbook, both the 11/44 and 11/70 have the general registers at memory addresses for manipulating from the front panel/console. Other do as well, but I'm not going to read through all documentation right now.
(The 1979 processor handbook, page 329 shows it for the 11/70 anyway.)
Johnny
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