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No More Secrets v0.91   [2016]

Released by :

Release Date :
24 December 2016

Type :
C64 Papermag

NMOS 6510 Unintended Opcodes

User rating:**********  10/10 (16 votes)   See votestatistics

Credits :
Text .... Groepaz of Dienstagstreff, Hitmen, VICE Team

Download :
http://csdb.dk/getinternalfile.php/153783/NoMoreSecrets-NMOS6510UnintendedOpcodes-20162412.pdf (downloads: 1538)

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User Comment
Submitted by tlr on 19 November 2017
Re: "and may even not exist at all" - seems to me it's an issue of contradiction rather than a case of missing proof. :)
You're just making the mistake of thinking digital when it's an analog behaviour.

I guess that's the source of Visual6502's discrepancies as well. I might be wrong here but AFAIK it doesn't try to model the analog behaviour at all. Does ANE give any of the $ee stuff in it?
User Comment
Submitted by Groepaz on 19 November 2017
BTW - everyone please try if the ANE opcode works as advertised on their C64s. i am looking for ppl with machines where it does not :) (you can eg use aneb.prg from lorenz suite to check, when it fails - speak up!)
User Comment
Submitted by Groepaz on 19 November 2017
not really. visual6502 is _not_ a proof. a bunch of details give different results there as they give on the real thing. i couldnt verify it on any of my C64s at least.

edit: now you say it... the first comment refers to all opcodes in that group. i could not prove one of them (i forgot which). will have to check again, i guess (i have a few more working C64s now too...).
User Comment
Submitted by Krill on 19 November 2017
p. 38 (44):
For this reason you should generally keep your index in a range that page boundaries are not crossed. This anomaly seems to exist on some chips only, and may even not exist at all.

p. 41 (47):
page boundary crossing may not work as expected (the page where the value is stored may be equal to the value stored).
page boundaries: CPU/shxy/shxy1.prg
page boundary crossing anomaly: http://visual6502.org/JSSim/expert.html?graphics=f&a=0&steps=18..

Re: "and may even not exist at all" - seems to me it's an issue of contradiction rather than a case of missing proof. :)
User Comment
Submitted by Groepaz on 17 November 2017
please provide a test program - nothing in this document will change unless backed up by test code :)
User Comment
Submitted by Cruzer on 17 November 2017
Just tested page crossing with SHX/SHY on a real machine, and the page indeed changes to the value stored. So you can drop the "and may even not exist at all" on page 38.
User Comment
Submitted by ChristopherJam on 21 September 2017
This is excellent, thank you.
User Comment
Submitted by Kylearan on 16 June 2017
Awesome, thanks a lot! Especially the appendix about opcode naming is exactly what I need right now for finishing my custom assembler/linker. :)
User Comment
Submitted by JAC on 3 January 2017
Even tough you update only once a year, you are still faster than the updates of my IDE. Let's see if I can change that in 2017 finally ;-)
User Comment
Submitted by Conjuror on 28 December 2016
Thanks for your great work here Groepaz. This is now the standard reference for this information.
User Comment
Submitted by Viktor on 26 December 2016
Nice work.
Where can I find the FLI-Sudoku?
User Comment
Submitted by Trap on 25 December 2016
Great work, Groepaz. Sharing is caring. Thanks a lot!!!
User Comment
Submitted by CRT on 24 December 2016
User Comment
Submitted by Dr.j on 24 December 2016
wow... a lot of efforts put on this one. many thanks for the "no more secrets" document. good job for uncover the secrets of the 6510 opcodes
User Comment
Submitted by soci on 24 December 2016
There are indeed no more secrets ;(

Btw. it's interesting to see monospaced program listings using "fi" (fi) and "fl" (fl) ligatures ;)
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