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MEGA65 Manual - typos / errors / suggestions

  • Yes, there has been quite a lot added to the MEGA65 Book in the last week or two. There are likely to be some errors hiding in there to be chased out, so we would very much appreciate some fresh eyes on it.


    LG

    Paul.

    I dl'd it and will read it in the next week, but as I said elsewhere: english ist NOT my native language.

    Anyway: if I find typos, I will tell report them here.

    :-D

  • Reports from proof readers are welcome.

    What I have found so far:


    Virtually every instance of implied addressing (1-byte instruction) is described as immediate addressing (2-byte instruction) instead.


    In the 4502 chapter, LDA is described as "undocumented instruction that loads a and x", possibly a copy-and-paste mistake.

    SBC is described as being affected by the status of the D flag. Does this mean the known bug in the 65CE02 is fixed? Then it would no longer be compatible to a real C65.


    In the 6502 section, DEC is said to be able to decrement the accumulator (correct for 4502, wrong for 6502).

  • The section about the unintended opcode SAX seems to confuse two different things:

    The text describes the opcode $cb (which does X = A&X minus arg), but the table holds information about opcodes $83/87/8f/97 (these just store A&X to target address).


    I guess the reason for this mistake is the fact that different sources of information use different mnemonics for the same opcodes, or (as in this case) the same mnemonic for different opcodes.


    As the information on unintended opcodes in this manual is incomplete anyway (and partially out of date), I strongly suggest to remove it completely and just add a link to "No More Secrets" instead.

    The only thing that is then really needed in the manual is a statement like

    "In 6502 mode, the 45GS10 supports the unintended opcodes $0b, $2b, [complete list here].

    It does not yet support the unintended opcodes $02, $12, [complete list here]."

  • As the information on unintended opcodes in this manual is incomplete anyway (and partially out of date), I strongly suggest to remove it completely and just add a link to "No More Secrets" instead.

    I think that a link in a printed manual (as intended by the Mega65 team) a not so good idea.


    First, if I have a printed book, I want to read exactly in this book. No need to use internet for content understanding.


    And second, no one knows how long the link guides to the right content. Internet is changing every second. The Mega65 is build to live more than 100 years as it is! ;)

  • First, if I have a printed book, I want to read exactly in this book. No need to use internet for content understanding.


    And second, no one knows how long the link guides to the right content. Internet is changing every second.

    Then print out the "No More Secrets" PDF. As long as there is no final spec for the native mode, duplicating already existing information about undocumented opcodes is just a waste of precious time.

  • First, thanks heaps for spotting the errors. Bonus points if you can file issues for them on github.com/mega65/mega65-user-guide/issues. Please just one point per issue, so that we can more easily work through them.


    Second, thanks for the pointer to No More Secrets. I had a nagging suspicion that there was a better resource than the one I could remember, but I couldn't remember what it was. We will go through and check for discrepencies against it.


    Meanwhile, the 65CE02 SBC bug: I had forgotten about it, but we did look at it back in 2014: http://cbm-hackers.2304266.n4.…ev-2B-C65s-td4659427.html

    That's a lot of sleeps ago, so I have to reload into my brain what the problem is, and what we did about it.

    Ok, digging through, it looks like we took the sensible path and fixed the bug.


    In terms of C65 compatibility, I am not particularly worried, as decimal SBC was so broken on the 4510, and there is so little C65 software, that I think we can safely say that there is no negative impact of fixing it. It's a bit like how DEC $D019 doesn't work to clear VIC-III IRQs, because the dummy write was optimised out of the RMW instructions. We added it back in, if and only if the argument is $D019. Negative impact on C65 software is theoretical, while the compatibility improvement for C64 software is tremendous.


    As for including a link in the printable book, we may well point users to that source, but we will ensure that the documentation of all unintended opcodes is complete in the book itself, even if this means a bit more work for us. We want the book to be complete and a delight and trustworthy to use.


    LG
    Paul.

  • Manual Page 28:


    If your MEGA65’s System Partition has become corrupt, you may be prompted to press

    F14 to correct this, i.e., hold SHIFT and tap the F13 key, with a display like the

    following:


    Here I miss the Screensot.


    If you do, you will need to use F7 to save the reset configuration, as otherwise the reset

    data will not have been written back to the MEGA65 System Partition.

    Once you have dismissed that display, or if your MEGA65 System Partition was not corrupted,

    you can now begin exploring and adjusting various settings. The programme allows

    the use of the keyboard, or optionally, an Amiga(tm) or C1351 mouse to control the

    programme.


    This last word, should it not be -> program (without 'me' @ the end) ?


    Manual Page 29:


    • Restore Factory Defaults allows to you reset the MEGA65 configuration settings to

    the factory defaults. It also randomly selects a new MAC address for models that

    include an internal Ethernet adaptor. If you wish to commit these changes, you must

    still save them.


    Either 'you' is to much OR it sould be 'you to' instead of ''to you'.


    As always: I guess so, coz anglo-saxxon ist not my native tongue ;-)


  • Manual Page 45:


    This section summarises how the MEGA65 selects which core to start when it is poweredon. The process is as shown in the following figure: When the MEGA65 is powered on,

    it always starts the bitstream stores in slot 0 of the flash.


    Should this not be -> stored??


    On Page 46 several times you wrote -> programme instead of program.

    I checked with Google Translate. in Box 'Häufigkeit' there are 3 bullets for program and only one bullet for programme, so I guess both are right, but the first one (program) 'feels' more common.

    Maybe/Perhaps programme is ausie-anglo-saxxon? ;-)

  • Hello,


    Thanks for the corrections! For the guide we have (for now at least) opted for "programme" instead of "program" to give it a more 1980s feel to the language.

    In the C64 Programmer's Reference Guide from 1982 they used "program".




    The use of "programme" is very uncommon in a description of a computer (the C64 was an US machine), even in the 1980s. And nowadays it feels utterly "wrong" - outside some very "exclusive" British clubs. ;)

  • I've read the Book. Very large, many sites :-)


    First thing I noticed, it's unstructured. I mean, it's supposed to invite programming, right?


    This is the structure like it is:


    1. Introduction

    2. Setup

    3. Getting Started

    4. Configuring (false place)

    5. Cores and Flashing (false place)

    6. How Computers work

    7. C64. C65 and Mega 65 Modes

    Hardware

    8. Using a Nexys 4DDR (false place)

    V APPENDICES (false place)

    A ACCESSORIES (false place)

    B BASIC 10 (false place)

    .

    .

    Element Catalogue (false place)

    Graphics Symbols (false place)

    .

    .

    Sprite Grids (false place)

    Balloon Sprite (false place)


    -------------------------------------------


    4 and 5 should be placed inside APPENDICES

    Because A MEGA65 should be delivered complete ready to use. Configuration is a tuning, APPENDICES thing.


    B Basic 10 is a programming thing and should be at 7

    7 Modes should be at 8

    Graphics Symbols , Sprite Grids and Balloon Sprite should be at 9


    The only question you have to ask yourself is, what are the first steps towards your own program. In the end, the hardware is discussed for the "extended" understanding: APPENDICES


    The MEGA65 needs programmers, first, not technicians ;-)


    Take a look into the C64 Handbook... this is nearly perfect. Programming first.


    And it should be bigger... it would be nice, if it also included the start of assembler programming with examples. I would program for the Mega65, but only with extensive documentation and many examples. You have to make it "palatable" to people :-)


    Try to make a C65 Bible with 1500 pages (Hardware/Software examples with Userport, Expansionsport, ...) ... think big ;-)