Subject: Re: [stella] Undocumented opcodes From: "Thomas Jentzsch" <tjentzsch@xxxxxx> Date: Mon, 20 Oct 2003 09:38:43 +0200 |
C. Bond wrote: > There are a few 6502 articles on the net which give the function and > timing of miscellaneous undocumented opcodes. Unfortunately, the timings > given for some opcodes, with indexing, do not seem to account for page > crossing. According to the CPU model in the hardware manual, an extra > cycle is almost certainly required in certain cases and some these do > not agree with the numbers in the articles. Has anyone verified the > cycle count for undocumented opcodes? No, I haven't verified these, but I would be very surprised if the general rules wouldn't be valid for those too. If an index crosses a page boundary there *must* be an additional cycles added. And you can check e.g. the z26 source code for the implementation of all illegal opcodes. Have?fun! Thomas _______________________________________________________ Thomas?Jentzsch?????????|?***?Every?bit?is?sacred?!?*** tjentzsch?at?web?dot?de?| ______________________________________________________________________________ Horoskop, Comics, VIPs, Wetter, Sport und Lotto im WEB.DE Screensaver1.2 Kostenlos downloaden: http://screensaver.web.de/?mc=021110 ---------------------------------------------------------------------------------------------- Archives (includes files) at http://www.biglist.com/lists/stella/archives/ Unsub & more at http://www.biglist.com/lists/stella/
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