[fpc-devel]Re: Latest status

patrick mergan patrick.mergan at village.uunet.be
Fri Nov 30 00:25:39 CET 2001

No, no!
It simply means :  Host Computer Failure
( ... however, the abbreviation is sometimes used for 'Hexadecimal Code
Fragment' )

Patrick Mergan
email : patrick.mergan at village.uunet.be
-----Original Message-----
From: Anton Tichawa <anton.tichawa at chello.at>
To: fpc-devel at deadlock.et.tudelft.nl <fpc-devel at deadlock.et.tudelft.nl>
Date: Thursday, November 29, 2001 10:57 PM
Subject: Re: [fpc-devel]Re: Latest status

>Let me contribute a totally different version of the HCF thing .. I
>programmed 8-bit microprocessors in the early 1980s, and I remember of
>one -undocumented- instruction, that caused the processor (I think, 6502,
>6800 or somthing like that) to increment it's address lines forever. I don't
>remember if it really was CF, but if someone is interested in this I can
>look for it.
>We actually used this instruction, because a processor simply incrementing
>it's address lines is very helpful in finding hardware errors, because
>nearly every pin in the whole system then shows a certain 'signature' (that
>is, low - high - transitions over all 65536 addresses). After executing this
>HCF instruction, we could compare the signal on each pin with a printout of
>an error-free hardware.
>I don't know about a fire, but I agree that the power consumption may rise
>in this mode.
>I don't know either, if this instruction was really a flaw or if it was
>intentionally designed for hardware testing.
>Hope I could add some confusion to this myth.
>----- Original Message -----
>From: Alan Grimes <alangrimes at starpower.net>
>To: <fpc-devel at deadlock.et.tudelft.nl>
>Sent: Thursday, November 29, 2001 7:28 PM
>Subject: Re: [fpc-devel]Re: Latest status
>> Florian Klaempfl wrote:
>> > >The worst thing about current IA64 is the carry-over of legacy
>> > support. A dual instruction set chip is the most disgusting thing I've
>> > ever heard of... Okay its not as bad as HCF but it's close. =P DAMN!!!
>> > Sorry, but what is HCF?
>> An old computer myth.
>> There was once a machine with a serious hardware flaw such that entering
>> a certain bad opcode, lets call it "HCF", caused the machine to go into
>> a strange halt state in which the address lines coming out of the
>> processor are toggled in a rapid-feedback loop. As you know, changing
>> the state of a line requires an expense of energy which causes the
>> release of heat. The ultra-rapid toggling of these lines would lead to
>> an immense heat buildup eventually causing a fire. So HCF has the effect
>> of causing the machine to Halt and Catch Fire. =P
>> Google should be very helpful in giving more inf0z...
>> --
>> Waiting for a typical DOS application to crash is like waiting for hell
>> to freeze over.
>> http://users.erols.com/alangrimes/  <my website.
>> _______________________________________________
>> fpc-devel maillist  -  fpc-devel at lists.freepascal.org
>> http://lists.freepascal.org/mailman/listinfo/fpc-devel
>fpc-devel maillist  -  fpc-devel at lists.freepascal.org

More information about the fpc-devel mailing list