Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!watmath!clyde!bonnie!akgua!sdcsvax!dcdwest!ittvax!decvax!genrad!mit-eddie!godot!ima!zurton!devoz From: devoz@zurton.UUCP Newsgroups: net.micro.apple Subject: Re: Undocumented 6502 Opcodes Message-ID: <9@zurton.UUCP> Date: Wed, 27-Feb-85 03:38:46 EST Article-I.D.: zurton.9 Posted: Wed Feb 27 03:38:46 1985 Date-Received: Sun, 3-Mar-85 05:33:03 EST Lines: 31 Nf-ID: #R:aicchi:-37600:zurton:5800001:000:1021 Nf-From: zurton!devoz Feb 24 13:05:00 1985 I wouldn't put much stock in a HCF instruction, considering the VAST number of 6502 based machines. Think about it. With the amount of "hacking" done on these, surely large numbers would have accidently executed HCF instructions and burst into flames. (hee hee hee). I do support the theory that there may be an instruction, or types of instructions, that, when executed, causes a Degradation of the Instruction Set, killing off many instructions, and maiming others. If you program in 6502 you know exactly what I mean. A sample of Destructive Op Codes: DHXI - Destroy Half of the X Index register DHYI - Destroy Half of the Y Index register AWID - Always Wander Into Decimal mode There are more. Supposedly during chip testing of the first few million devices, the original manufacturer wrongly executed these instructions, limiting the power of the 6502 forever, or until the 65816 arrives. (Ahhhh, the price of compatibility). ddddddddeeeeeeeevvvvvvvvvoooooooozzzzzzzzzz