[cctalk] Re: System 360 question

On 1 Nov 2024, at 23:00, Peter Coghlan via cctalk <cctalk(a)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(a)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 > barto(a)kdbarto.org > >