Can someone explain how the Intel 8008 (yes, the 8008, NOT the 8080!)
handled saving and restoring the flags during an interrupt?
The 8008 has four flag bits - CZS&P - but there doesn't seem to be any
explicit equivalent to the PSW register nor any "PUSH PSW" or "POP PSW" type
instructions. Other than testing the flag bits with the JUMP/CALL/RET
instructions there doesn't seem to be any way to access them.
Interrupts work pretty much like the 8080 - during the interrupt response
the peripheral forces an instruction onto the bus, typically an RST opcode
but in theory it could be anything. RST and CALL however only appear to
save the PC on the internal stack, and RET only restores the PC. So how do
you save and restore the flag bits?
It seems like interrupts would be pretty much useless without this, so I
must be missing something.
Thanks,
Hi there,I recently completed recreations of the Sol Intelligent Terminal and JOLT PCBs and have had a bunch produced if anyone is interested.But the real reason I am writing is I want to tackle a much more difficult project which is the RGS-008, which came out around the time of the Altair and was condemned obsolescence almost immediately following release.I am trying to track down any surviving copies of schematics or documentation. I have already reached out to CHM and a couple other folks but so far actual documentation remains elusive. CHM does have an RGS-008 based on the original wire wrap design, but no schematics.Probably these things are hard to find for a reason, but I thought I might reach out here to see if anyone has any other leads I could possibly follow. I suspect the basic design followed the reference design supplied by Intel, with some modifications. Many thanks and Happy New Year!BradSent from my Galaxy
Hey all -
I came across a big box of 12 of these disks which my dad acquired through
work back in the 70s, and squirreled them away in the attic after they had
copied the data. 4 of them have a broken metal access door. I opened one of
the broken ones (in a clean of an environment as possible) to see what was
going on inside. It looks like the door is held on by plastic divets that
have broken off. They might be able to be repaired with small screws. I
have no idea if these are functional or not. I am offering them up for free
for anyone that can use them. I'm willing to ship or you pick up in San
Diego.
Here is a link to photos of them:
https://drive.google.com/drive/folders/1wnzqjAtiq44MGU-wDJR-AQdzu-Mkyii8?us…
-Kurt
