utoddl@uncecs.edu (Todd M. Lewis) (11/03/89)
Since I put an A590 on my A1000, I've been getting regular visits from the Guru. Specifically, 0000000B.00C0279A. It's always 00C0279A. I know that the B means "Line F (1111) Emulation", but just what is line F emulation? All the books I've found on the 68000 say something like "line A and line F emulation are beyond the scope of this book, and you won't ever need to know about it anyway." Humph! Do I have faulty memory at 00C0279A? If I allocated this RAM (somehow?) and didn't free it, would that keep other programs from using it and thereby avoid the Guru? Would grounding my PALs help? (I plan to do this anyway--Thanks Bill Dirks!) The "C0.." memory is 1.5Mb on a Spirit Tech. board which pluggs into the processor socket. Is this unit Ok to use with the A590? It's worked fine for a couple of years without the disk. I can live with the occasional Guru, but my wife needs a reliable system and I would really like to keep the hard disk. Comments and suggestions are welcome. _____ | Todd M. Lewis Disclaimer: If you want my employer's ||\/| utoddl@ecsvax.uncecs.edu ideas, you'll have to || || utoddl@ecsvax.bitnet _buy_ them. |___ ("Prgrms wtht cmmnts r lk sntncs wtht vwls." --TML)
mph@behemoth.phx.mcd.mot.com (Mark Huth) (11/08/89)
F line emulation is a technique which allows instruction set extension on the 68xxx family. An F-line exception occurs when an instruction with the first nybble of the opcode is F (1111 binary). The exception handler is entered, which may then examine the rest of the instruction and emulate just about anything you'd like. Getting an F-line exception in normal code is usually the result of jumping to a word which isn't actually an instruction boundary. It may also be caused by faulty memory, which returns Fxxx instead of the correct value. Additionally, the FPU opcodes reside in the Fline space, so if you have inline FPU operations, they will trap, allowing software emulation. Hope that helps. Mark Huth
utoddl@uncecs.edu (Todd M. Lewis) (11/09/89)
[I was getting Line F emulation gurus on an A1000 after adding an A590 hard disk.] In article <11965@behemoth.phx.mcd.mot.com>, mph@behemoth.phx.mcd.mot.com (Mark Huth) writes: > F line emulation is a technique which allows instruction set extension > on the 68xxx family. An F-line exception occurs when an instruction > with the first nybble of the opcode is F (1111 binary). The exception [...] > Hope that helps. > > Mark Huth Thanks, Mark. That does help. It explains that problem and several others I was having, all of which have cleared up just fine after grounding my PALs. The A590 is a sweet little unit. I may even pick up a few RAM chips for it soon. Thanks for the explanation, Todd M. Lewis