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From: john@x.UUCP (John Woods)
Newsgroups: net.micro.apple
Subject: Re: Re: Undocumented 6502 Opcodes
Message-ID: <421@x.UUCP>
Date: Fri, 8-Mar-85 15:25:50 EST
Article-I.D.: x.421
Posted: Fri Mar  8 15:25:50 1985
Date-Received: Mon, 11-Mar-85 06:57:39 EST
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Organization: Charles River Data Systems, Framingham MA
Lines: 14

> $12.  I think that there must be some truth in the HCF instruction for the

As I have heard it, the "HCF" instruction which is often found in 6800s and
6502s is intended for QA at the factory:  the intent is that you feed the chip
the magic instruction, and watch what happens:  it is supposed to count on the
address lines, from 0 to 65535, forever.  This [roughly] validates the address
drivers as well as much of the internal logic.  Those who have been looking
for the HCF instruction on their favorite micros might watch the address
lines to see if this is true.
-- 
John Woods, Charles River Data Systems, Framingham MA, (617) 626-1101
...!decvax!frog!john, ...!mit-eddie!jfw, jfw%mit-ccc@MIT-XX.ARPA

Sorry, I don't feel deep right now.