The 6800 had an "HCF" instruction. The 6502 had several KIL instructions that had similar behaviour. I don't think either of these made any permanent damage.
https://en.wikipedia.org/wiki/Halt_and_Catch_Fire_(computing) https://www.pagetable.com/?p=39 https://en.wikipedia.org/wiki/Killer_poke > On 1 Nov 2024, at 23:00, Peter Coghlan via cctalk <cctalk@classiccmp.org> > wrote: > > > Nope. If you believe this mythical instruction exists, you are the > person that gets to spend the time digging up the references to it. > > I've been writing assembly on the 6502 since the early 1980s and I have > never managed to damage one when my programs went off the rails, which > they did on many occasions. > > I have never heard from any other 6502 users about issues like this either. > > Regards, > Peter Coghlan. > > David Barto wrote: >> >> Nope. Read the documentation for the chip. Turns out that the HCF >> instruction basically sent the chip into an internal loop which would render >> parts of it unusable after about 30-45 seconds. >> >> Tried it once and the chip got hot. Very very hot and then just stopped >> working. >> >> David >> >>> On Nov 1, 2024, at 9:55 AM, Peter Coghlan via cctalk >>> <cctalk@classiccmp.org> wrote: >>> >>> David Barto wrote: >>>> >>>> The 6502 had a HCF (halt and catch fire) undocumented instruction. >>>> I forget the opcode and if you knew what you were doing you could get the >>>> instruction executed on the chip using any assembler. >>>> >>>> Security through obscurity back in the 70s. >>>> The chip was advanced enough that the DOD wanted to avoid it falling into >>>> the “wrong” hands. >>>> >>>> David >>>> >>>> Sent from iPhone Hotblack Desiato >>>> >>> >>> Did someone tell you this on April 1st? >>> >>> Regards, >>> Peter Coghlan >>> >>> Sent from my DEC Alphaserver 800 >> >> There is nothing more difficult to carry out, nor more doubtful of success, >> nor more dangerous to handle, than to initiate a new order of things. >> For the reformer has enemies in all those who profit by the old order, >> and only lukewarm defenders in all those who would profit by the new... >> --Niccolo Macchiavelli, The Prince >> David Barto >> ba...@kdbarto.org >> >>
