Posted By
SVS
on 2016-02-20
13:52:56
 |  6502 code $x2
Since ever I wondered why all the executing codes, of 6502 family, with "2" as second nibble are jamming the processor. For example: $02, $12, ... $82, $92 etc.
The only exception to this rule is $A2 (LDX).
Who know the mystery?
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Posted By
Doug
on 2016-02-21
18:55:49
| Re: 6502 code $x2
Hi,
Best article I've read on it: http://www.pagetable.com/?p=39
I used a lot of unlisted op codes in the past to obfuscate code. Some were like multibyte NOPs, which confused disassemblers! Others did 'odd' but useful stuff. This article gives a really good explanation of why.
Doug
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Posted By
gerliczer
on 2016-02-22
02:49:49
| Re: 6502 code $x2
Thanks a lot, Doug. I wanted to recommend this article to SVS but I couldn't find it.
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Posted By
SVS
on 2016-02-22
06:49:09
| Re: 6502 code $x2
Thus they are so called KIL opcodes! Very interesting, thank you.
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