ANN: open82 - Sinclair

This is a discussion on ANN: open82 - Sinclair ; open82 is a fully open source replacement for the ZX Spectrum firmware. It is currently about 50% complete, but you can use a copy of the original ROM during assembly to produce a fully functional ROM. The project is hosted ...

+ Reply to Thread
Results 1 to 16 of 16

Thread: ANN: open82

  1. ANN: open82

    open82 is a fully open source replacement for the ZX Spectrum
    firmware.

    It is currently about 50% complete, but you can use a copy of the
    original ROM during assembly to produce a fully functional ROM. The
    project is hosted in a subversion repository on sourceforge. Email me
    if you want to get involved.

    Before anyone starts screaming blue murder again:

    open82 is copyright (c) 1981 Nine Tiles Networks Ltd.

    I have reorganized John Grant, Steve Vickers and Andrew Wright's code
    around the framework provided by Ian Logan and Frank O'Hara's
    'Complete Spectrum ROM Disassembly'. The assembly file is based on the
    'uncommented spectrum rom assembly' which I put into the public domain
    earlier this month. All code is used with permission and distributed
    under the GPL.

  2. Re: open82

    Well thanks, I did not understand a word of it, but thanks anyway!

    Brian

    --
    Brian Gaff....Note, this account does not accept Bcc: email.
    graphics are great, but the blind can't hear them
    Email: briang1@blueyonder.co.uk
    __________________________________________________ __________________________________________________ __________


    "OwenBot" wrote in message
    news:20f53c6c-d719-461f-b6c6-55b9833e0a87@d1g2000hsg.googlegroups.com...
    > open82 is a fully open source replacement for the ZX Spectrum
    > firmware.
    >
    > It is currently about 50% complete, but you can use a copy of the
    > original ROM during assembly to produce a fully functional ROM. The
    > project is hosted in a subversion repository on sourceforge. Email me
    > if you want to get involved.
    >
    > Before anyone starts screaming blue murder again:
    >
    > open82 is copyright (c) 1981 Nine Tiles Networks Ltd.
    >
    > I have reorganized John Grant, Steve Vickers and Andrew Wright's code
    > around the framework provided by Ian Logan and Frank O'Hara's
    > 'Complete Spectrum ROM Disassembly'. The assembly file is based on the
    > 'uncommented spectrum rom assembly' which I put into the public domain
    > earlier this month. All code is used with permission and distributed
    > under the GPL.




  3. Re: open82

    Does this help? Because Amstrad imposes restrictions on the use of the
    Spectrum ROM there is a need for a replacement that is unencumbered by
    those restrictions. This is the second attempt at such a ROM, the
    first being Matt Westcott's OpenZXRom project. The practical upshot of
    either project being finished (and it really doesn't matter which is
    first to be completed) is that you will be able to sell home-brew
    Spectrum clones with a built-in Sinclair BASIC compatible ROM.

  4. Re: open82

    > The practical upshot of either project being finished [..]
    > is that you will be able to sell home-brew Spectrum clones


    Sell? It would amaze me if you could give them away.


  5. Re: open82

    Simon Brattel wrote:
    >> The practical upshot of either project being finished [..]
    >> is that you will be able to sell home-brew Spectrum clones

    >
    > Sell? It would amaze me if you could give them away.


    Sorry, didn't mean to rain on anyone's parade. Don't even know what made
    me write that, let alone post it... [dozes off again]


  6. Re: open82

    On Sep 3, 10:35*pm, Simon Brattel wrote:
    > Simon Brattel wrote:
    > >> The practical upshot of either project being finished [..]
    > >> is that you will be able to sell home-brew Spectrum clones

    >
    > > Sell? It would amaze me if you could give them away.

    >
    > Sorry, didn't mean to rain on anyone's parade. Don't even know what made
    > * me write that, let alone post it... [dozes off again]


    Not at all. It's a fair comment. However, I've investigated the market
    and while there is no margin in manufacturing Spectrum clones, there
    is a very tiny market for selling kit based retro-computers to
    electronics enthusiasts (although it would be hard to do much more
    than break even). It helps if the computer you build is able to draw
    on a large software base. One advantage of the clone that is the
    reason behind me starting this project is that it in addition to
    running the majority of Spectrum software, it can also emulate a large
    number of other 8-bit systems.

  7. Re: open82

    OwenBot wrote:
    > On Sep 3, 10:35*pm, Simon Brattel wrote:
    >> Simon Brattel wrote:
    >> >> The practical upshot of either project being finished [..]
    >> >> is that you will be able to sell home-brew Spectrum clones

    >>
    >> > Sell? It would amaze me if you could give them away.

    >>
    >> Sorry, didn't mean to rain on anyone's parade. Don't even know what made
    >> * me write that, let alone post it... [dozes off again]

    >
    > Not at all. It's a fair comment. However, I've investigated the market
    > and while there is no margin in manufacturing Spectrum clones, there
    > is a very tiny market for selling kit based retro-computers to
    > electronics enthusiasts (although it would be hard to do much more
    > than break even). It helps if the computer you build is able to draw
    > on a large software base. One advantage of the clone that is the
    > reason behind me starting this project is that it in addition to
    > running the majority of Spectrum software, it can also emulate a large
    > number of other 8-bit systems.


    With the new ROM... there is one major problem with rewriting routines...
    How about compatibility? Lots of games make calls to very odd places in the
    rom where hidden code (maybe even code not meant to be access from the
    outside) can reduce the size of a program.
    --
    | spike1@freenet.co.uk | |
    | Andrew Halliwell BSc | "The day Microsoft makes something that doesn't |
    | in | suck is probably the day they start making |
    | Computer science | vacuum cleaners" - Ernst Jan Plugge |

  8. Re: open82

    Andrew Halliwell wrote:
    > With the new ROM... there is one major problem with rewriting routines...
    > How about compatibility? Lots of games make calls to very odd places in the
    > rom where hidden code (maybe even code not meant to be access from the
    > outside) can reduce the size of a program.


    Ah, that's where OpenZXRom comes in: http://matt.west.co.tt/openzxrom/
    Aiming to match every entry point likely to be used by games (on the
    basis that there probably aren't that many: what sort of game is going
    to hook into the ROM code for syntax checking, or shuffling the Gosub
    stack around, or...?), but unlike open82, not particularly oriented
    towards building a nice Basic programming environment.

    I imagine the OwenBot also has some ideas about loading/paging in the
    original ROM from software, to get around the sticking points in the
    licence.

  9. Re: open82

    > Not at all. It's a fair comment. However, I've investigated the market
    > and while there is no margin in manufacturing Spectrum clones, there
    > is a very tiny market for selling kit based retro-computers to
    > electronics enthusiasts (although it would be hard to do much more
    > than break even).


    Well, good luck with it (not meant sarcastically)...

    I share Andrew's misgivings about compatibility, there were some really
    dodgy programmers out there (when are there not) and it wouldn't
    surprise me at all to find some of 'em had relied on the ROM contents
    being fixed. Mind you, I don't suppose it really matters too much if the
    odd few neolithic applications fail

  10. Re: open82

    On Tue, 09 Sep 2008 01:25:20 +0100 da kidz on comp.sys.sinclair were rappin'
    to MC Simon Brattel:

    > I share Andrew's misgivings about compatibility, there were some really
    > dodgy programmers out there (when are there not) and it wouldn't
    > surprise me at all to find some of 'em had relied on the ROM contents
    > being fixed.


    When I was helping Andrew (OwenBot) test his SE Basic ROM, we
    discovered that Theme Park used a sequence of bytes from the ROM for
    one of the graphics.

    Chris


    --
    +-------------------------------------------+
    | Unsatisfactory Software - "because it is" |
    | http://www.unsatisfactorysoftware.co.uk |
    | Your Sinclair: A Celebration |
    +- http://www.yoursinclair.co.uk -----------+

    DISCLAIMER: I may be making all this stuff up again.

  11. Re: open82

    One I remember is the game "The Penetrator" (not "Penetrator").

    This relies on a table of bytes at offset 59 into the standard ROM to
    check against as a kind of primitive copy protection. It asks the user
    to enter a selected byte from that area before the game will start.

    The game would still start on a modified ROM, but the list of copy-
    protection numbers would be different. (or this scheme could be simply
    bypassed).

  12. Re: open82

    Sorry for the lateness of the reply.

    As far as compatibility is concerned, open82 is only aiming for
    compatibility with BASIC, i.e. a program written using the original
    ROM should run, unmodified, under open82.

    Matthew is quite correct, my solution for games compatibility is -
    load OpenZX, or the original ROM in software. Certain games, e.g.
    Travel With Trashman, will not load with anything other than the
    original ROM because they checksum it as a copy-prevention measure.
    Digital Prawn mentions "The Penetrator" and I'm sure there are other
    games that do this as well.

    I think Chris is actually thinking of "Roller Coaster" which naughtily
    uses a series of #FFs near the end of the ROM for one of its sprites.
    There are also games that use a sequence of 257 #FFs as IM2 tables,
    however only the first two bytes are really necessary providing you
    don't have floating-bus issues (as demonstrated by GW03).

  13. Re: open82

    On 12 Sep, 09:40, OwenBot wrote:

    > There are also games that use a sequence of 257 #FFs as IM2 tables,
    > however only the first two bytes are really necessary providing you
    > don't have floating-bus issues (as demonstrated by GW03).


    It was Matthew Westcott that first mentioned on css that the Sinclair
    machines did this. In fact I have checked online ROMs and it seems
    that all 128K 48K Basic ROMs including the Spanish one, have two $FF
    bytes at $38FF, $39FF, $3AFF, and $3BFF.
    The two ROMs for the Amstrad +3 (also used by the Plus2b) only have
    $FF bytes at $3BFF.

    I haven't checked real hardware but all pukka 128K Spectrums should
    return 255 with PRINT PEEK 15359 and PRINT PEEK 15360.

    Printing the contents of the memory locations 14591, 14592, 14847,
    14848, 15103 and 15104 should return 255 on all machines except the
    Plus 3 derivatives.

    Amstrad of course got it only part right some of the time.


  14. Re: open82

    On Fri, 12 Sep 2008 08:24:00 -0700 (PDT) da kidz on comp.sys.sinclair were rappin'
    to MC Geoff Wearmouth:

    > Amstrad of course got it only part right some of the time.


    Hence the oddness in things like Lemmings, where you get 128K sound
    only under certain models/ROMs.

    Chris


    --
    +-------------------------------------------+
    | Unsatisfactory Software - "because it is" |
    | http://www.unsatisfactorysoftware.co.uk |
    | Your Sinclair: A Celebration |
    +- http://www.yoursinclair.co.uk -----------+

    DISCLAIMER: I may be making all this stuff up again.

  15. Re: open82

    On Fri, 12 Sep 2008 01:40:49 -0700 (PDT) da kidz on comp.sys.sinclair were rappin'
    to MC OwenBot:

    > I think Chris is actually thinking of "Roller Coaster"


    Oops, that's what I meant. Theme Park of course wasn't released for
    the Spectrum.

    Chris


    --
    +-------------------------------------------+
    | Unsatisfactory Software - "because it is" |
    | http://www.unsatisfactorysoftware.co.uk |
    | Your Sinclair: A Celebration |
    +- http://www.yoursinclair.co.uk -----------+

    DISCLAIMER: I may be making all this stuff up again.

  16. Re: open82

    On 12 Sep 2008 19:38:16 +0100, "Chris Young"
    wrote:

    >On Fri, 12 Sep 2008 01:40:49 -0700 (PDT) da kidz on comp.sys.sinclair were rappin'
    >to MC OwenBot:
    >
    >> I think Chris is actually thinking of "Roller Coaster"

    >
    >Oops, that's what I meant. Theme Park of course wasn't released for
    >the Spectrum.
    >
    >Chris



    Rolo coaster?

+ Reply to Thread