Xref: utzoo rec.arts.sf-lovers:49266 alt.cyberpunk:4933 comp.arch:19077 Path: utzoo!utgpu!cs.utexas.edu!usc!julius.cs.uiuc.edu!apple!motcsd!dms!albaugh From: albaugh@dms.UUCP (Mike Albaugh) Newsgroups: rec.arts.sf-lovers,alt.cyberpunk,comp.arch Subject: 6502 interrupts (was Re: Count Zero Interrupt) Message-ID: <1176@dms.UUCP> Date: 8 Nov 90 15:38:54 GMT References: Organization: Atari Games Inc., Milpitas, CA Lines: 33 Followup_to: comp.arch From article , by ap1i+@andrew.cmu.edu (Andrew C. Plotkin): >> I believe this command exists in at least the 6502 microprocessor's >> vocabulary > > Nope. I'll agree with that. No such "command" exists, by that or any other name in any 6502 system with which I am familiar, and that includes a _lot_ of such systems, as I have been mucking with 6502s since I bought a 6501 at Wescon (1975 ?) :-) > I dearly love my old Apple 2; but I have to admit that the 6502 handles > interrupts the way a drunk gorilla handles fine china. The designers of the Apple-2 did a very poor job of handling interrupts, perhaps because the competition at the time (S-100 CPM boxes) typically ignored them totally. But to condemn a CPU architecture for the sins of one "OS" is misguided at best. The 6502 saves _exactly_ what is needed to restore the state of the processor on return, thus providing the minimum interrupt latency. This is one of the main reasons the 6502 was/is so popular in small embedded systems with high interrupt rates (e.g. video games). You may have no taste for such minimalism, but others find it a _feature_ :-) We now return you to your regularly scheduled programming... Mike | Mike Albaugh (albaugh@dms.UUCP || {...decwrl!pyramid!}weitek!dms!albaugh) | Atari Games Corp (Arcade Games, no relation to the makers of the ST) | 675 Sycamore Dr. Milpitas, CA 95035 voice: (408)434-1709 | The opinions expressed are my own (Boy, are they ever)