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Re: 6502 illegal opcodes questions

Subject: Re: 6502 illegal opcodes questions
From: Jim Brain <brain@jbrain.com>
Date: Fri, 19 May 2006 05:28:31 GMT
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Michael J. Mahon wrote:

What do you know!  The decoding *is* done with a PLA after all!

I don't think a PLA allows X (don't care) states. The large logicmatrix at the bottom of the diagram is a wired-or matrix, which is whythe illops exist.

Jim

Follow-Ups:
- Re: 6502 illegal opcodes questions
  - From: "Michael J. Mahon" <mjmahon@aol.com>
- Re: 6502 illegal opcodes questions
  - From: Eric Smith <eric@brouhaha.com>

References:
- 6502 illegal opcodes questions
  - From: Linards Ticmanis <ticmanis@gmx.de>
- Re: 6502 illegal opcodes questions
  - From: "mdj" <mdj.mdj@gmail.com>
- Re: 6502 illegal opcodes questions
  - From: Bruce Tomlin <bruce#fanboy.net@127.0.0.1>
- Re: 6502 illegal opcodes questions
  - From: "Michael J. Mahon" <mjmahon@aol.com>
- Re: 6502 illegal opcodes questions
  - From: heuser.marcus@freenet.de
- Re: 6502 illegal opcodes questions
  - From: "Michael J. Mahon" <mjmahon@aol.com>
- Re: 6502 illegal opcodes questions
  - From: heuser.marcus@freenet.de
- Re: 6502 illegal opcodes questions
  - From: "Sam Gillett" <samgillettnospam@diespammermsn.com>
- Re: 6502 illegal opcodes questions
  - From: "Michael J. Mahon" <mjmahon@aol.com>
- Re: 6502 illegal opcodes questions
  - From: usenet@spuddy.org (Stephen Harris)
- Re: 6502 illegal opcodes questions
  - From: "Michael J. Mahon" <mjmahon@aol.com>
- Re: 6502 illegal opcodes questions
  - From: Bruce Tomlin <bruce#fanboy.net@127.0.0.1>
- Re: 6502 illegal opcodes questions
  - From: "Michael J. Mahon" <mjmahon@aol.com>
- Re: 6502 illegal opcodes questions
  - From: Bruce Tomlin <bruce#fanboy.net@127.0.0.1>
- Re: 6502 illegal opcodes questions
  - From: "Michael J. Mahon" <mjmahon@aol.com>
- Re: 6502 illegal opcodes questions
  - From: John Selck <selck_j@informatik.hgv-hamburg.de>
- Re: 6502 illegal opcodes questions
  - From: "Michael J. Mahon" <mjmahon@aol.com>

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