Re: Proposed Assembler Commands

On Sat, 30 Apr 2005 18:11:23 -0700, John Larkin wrote:

> On Sat, 30 Apr 2005 22:45:45 +0100, Pooh Bear
> <rabbitsfriendsandrelations@xxxxxxxxxxx> wrote:
>
>>Mike Monett wrote:
>>
>>> To All,
>>>
>>> Microprocessors have become so simple that it seems anyone can program
>>> them nowadays. But think of what it was like when the first processors
>>> came out and you had to program around noisy circuits and unreliable
>>> memory.
>>
>>Rumour has it that the 6800 had an undocumented instruction.
>>
>>HCF - Halt and Catch Fire
>>
>
>
> It probably didn't work. The 6800 was an n-channel depletion-load
> chip. You need CMOS to start a decent blaze.

Hmm, I thought Moto and Intel were all p-channel at that time.

> I think it did have an opcode that would put it into a test mode that
> only a reset would fix.

The original IBM PC monochrome adapter allowed software to halt the
horixontal sweep, causing the monitor to let its magic smoke out. Oops.

--
Keith
.