Is there a Spectrum emulator for the C128? - Sinclair

This is a discussion on Is there a Spectrum emulator for the C128? - Sinclair ; >>>>> "VV" == Varga Viktor writes: VV> Maybe the hardest thing the different graphical memory structure VV> and/ or the speed. The C128 runs the Z80 at roughly half the speed of a spectrum, and the bitmap addressing is completely ...

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Thread: Is there a Spectrum emulator for the C128?

  1. Re: Is there a Spectrum emulator for the C128?

    >>>>> "VV" == Varga Viktor writes:

    VV> Maybe the hardest thing the different graphical memory structure
    VV> and/ or the speed.

    The C128 runs the Z80 at roughly half the speed of a spectrum, and the
    bitmap addressing is completely different, pretty much insuring that
    games won't run. The ROM is a non-issue, as you can just load a copy
    of it into RAM.

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  2. Re: Is there a Spectrum emulator for the C128?

    Hi, if it's possible to run the (128 emulated) C64 at 2Mhz i think
    that the emulated speccy will have the same speed of the original one !

  3. Re: Is there a Spectrum emulator for the C128?

    Old Speccyman did eloquently scribble:
    > Hi, if it's possible to run the (128 emulated) C64 at 2Mhz i think
    > that the emulated speccy will have the same speed of the original one !


    Errrrr... no
    The z80 in the spectrum doesn't run at 2Mhz.
    It runs at 3.5 Mhz.
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  4. Re: Is there a Spectrum emulator for the C128?

    spike1@freenet.co.uk wrote:
    > Old Speccyman did eloquently scribble:
    >> Hi, if it's possible to run the (128 emulated) C64 at 2Mhz i think
    >> that the emulated speccy will have the same speed of the original one !

    >
    > Errrrr... no
    > The z80 in the spectrum doesn't run at 2Mhz.
    > It runs at 3.5 Mhz.


    It would probably be easier to emulate a Vic 20 on the Spectrum. We've
    already got a working 6502 core (as used in the Apple I emulator).

  5. Re: Is there a Spectrum emulator for the C128?

    >>>>> "AO" == Andrew Owen writes:

    AO> It would probably be easier to emulate a Vic 20 on the Spectrum.
    AO> We've already got a working 6502 core (as used in the Apple I
    AO> emulator).

    CPU emulation is trivial, it's video emulation that's hard (aka slow).

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  6. Re: Is there a Spectrum emulator for the C128?

    On Jan 24, 9:42 pm, Jim Brain wrote:
    > I'd invite you to go read the postings by Bil Herd on USENET. The C128
    > was very much designed with a lot of thought. If Bil and his team
    > hadn't thought it through, well, who knows what we would have gotten.


    As a next stage to the Commodore 64, it was indeed well thought
    through. However, as a CP/M-Plus machine, the clock speed of the Z80
    left it almost fatally flawed. Given that running the Z80 at 8MHz with
    liberal use of wait states to synchronize to the 8502 bus was not
    possible with the Z80 as tightly integrated as it was in the system,
    then the commercial solution of that piece of the puzzle required less
    tight integration of the Z80.


  7. Re: Is there a Spectrum emulator for the C128?

    BruceMcF wrote:
    > On Jan 24, 9:42 pm, Jim Brain wrote:
    >> I'd invite you to go read the postings by Bil Herd on USENET. The C128
    >> was very much designed with a lot of thought. If Bil and his team
    >> hadn't thought it through, well, who knows what we would have gotten.

    >
    > As a next stage to the Commodore 64, it was indeed well thought
    > through. However, as a CP/M-Plus machine, the clock speed of the Z80
    > left it almost fatally flawed. Given that running the Z80 at 8MHz with
    > liberal use of wait states to synchronize to the 8502 bus was not
    > possible with the Z80 as tightly integrated as it was in the system,
    > then the commercial solution of that piece of the puzzle required less
    > tight integration of the Z80.


    That assumes it was designed as a CP/M PLus machine. It was not. Bil
    was against the idea of adding Z80 support, but Marketing had already
    touted the business uses, assuming people would buy the C64 CP/M cart to
    use it in that fashion. They were not aware (or chose to ignore) that
    the CP/M cart did not work on later models of C64, and barely worked on
    the older models. Bil was then faced with the insurmountable task of
    making a cart that didn;t even work on the C64 work with the C128.

    As Bil tells it, one night, he just "accidentally" designed the cart
    into the mainboard, to address the issue.

    Later on, the existance of the Z80 came to save the C128, as some
    cartridges abused the cartridge port signals to such an extent that they
    would not work right on the C128. Thus, on the C128, the Z80 starts up
    first, checks the cartridge port signals, sets the MMU, and then passes
    control to the 8502.

    But, I will submit that the Z80 was not a design goal at all. CBM would
    have been happy to pawn off the old Z80 CP/M cart on C128 buyers for
    CP/M usage had it worked.

    Jim

  8. Re: Is there a Spectrum emulator for the C128?

    There is a Sinclair Spectrum BASIC emulator for the Commodore 64 which
    runs at about 70% + speed when compared to running the same BASIC
    program on a Sinclair (depending on what it is doing, of course), will
    LOAD and SAVE programs from cassette tape and might even do LOAD ""
    SCREEN$ - but it won't do machine code, of course. It works really
    well considering the limitations. Now, I wonder if I can find it?

    Regards,

    Shaun.

  9. Re: Is there a Spectrum emulator for the C128?

    C256 wrote:
    > X-No-Archive: yes
    >
    > The Sinclair Spectrum, had many unique games that were
    > either never ported to the C64 or that were simply bad,
    > extremly slow and unplayable.
    >
    > I wonder if there's a Sinclair Spectrum emulator for the C128
    > which has a Z80 and 128K RAM and stuff to play the 48K
    > Spectrum games.
    >
    > Does such an emulator exist? Is there a way to emulate the
    > AY sound chip in a C128? Or is there a way to build-in
    > such a chip?


    You might well ask. The thing is, it's very difficult to emulate a
    machine that uses considerably different supplemental hardware, even if
    the CPU is the same.

    The problem is not in the CPU-intensive parts of the code; that would of
    course run identically. The problem is that for every hardware access,
    execution would have to be suspended in order to translate the necessary
    address, register, and/or flag from the original to the appropriate host
    value.

    Neither the VIC nor the VDC on the 128 is similar enough to the display
    hardware on the Spectrum to not require a rather extensive translation
    before what a Spectrum would display would be displayed on a 128. And
    the SID is similarly different from the AY.

    Those are the biggest examples, but even things like the VIA on the 128
    don't work the same as the equivalent hardware on the Spectrum. That
    affects things like storage devices and communications programs and
    joystick and mouse input.

    It's certainly possible to interface an AY sound chip to a 128. Would
    that be the secret to making a Spectrum emulator? No.

  10. Re: Is there a Spectrum emulator for the C128?

    Not sure about the c128 computer, but has anyone seen the Spectrum
    emulation on the Atari 8-bit? Even though it's monochrome, it's still
    impressive.

  11. Re: Is there a Spectrum emulator for the C128?

    MagerValp wrote:

    > CPU emulation is trivial, it's video emulation that's hard (aka slow).


    Hi!


    Yeah. They do no even run satisfying with fast PC's (fast enough well,
    but firstly crappy and dazzling and secondely not 100% emulated, e.g.
    Atari 400/800 Emulator, etc.), impossible to do with a 8bit GfX card...



    Best regards,

    Daniel Mandic

  12. Re: Is there a Spectrum emulator for the C128?

    Kelli Halliburton wrote:

    > It's certainly possible to interface an AY sound chip to a 128. Would
    > that be the secret to making a Spectrum emulator? No.


    An AY in a C-128 ;-).... he must be joking...

    That's the same if I would favor the C-128 Hardware Side for Games.

  13. Re: Is there a Spectrum emulator for the C128?

    retrocomtoday@aol.com wrote:
    > There is a Sinclair Spectrum BASIC emulator for the Commodore 64 which
    > runs at about 70% + speed when compared to running the same BASIC
    > program on a Sinclair (depending on what it is doing, of course), will
    > LOAD and SAVE programs from cassette tape and might even do LOAD ""
    > SCREEN$ - but it won't do machine code, of course. It works really
    > well considering the limitations. Now, I wonder if I can find it?
    >
    > Regards,
    >
    > Shaun.


    You can download it here:

    http://www.worldofspectrum.org/sincl.../versions.html

  14. Re: Is there a Spectrum emulator for the C128?

    MagerValp wrote:
    >>>>>> "AO" == Andrew Owen writes:

    >
    > AO> It would probably be easier to emulate a Vic 20 on the Spectrum.
    > AO> We've already got a working 6502 core (as used in the Apple I
    > AO> emulator).
    >
    > CPU emulation is trivial, it's video emulation that's hard (aka slow).


    True, but it should be possible to set up an interrupt driven display
    routine to convert the VIC information. Granted it's not going to run at
    100% speed, but it should be doable.

  15. Re: Is there a Spectrum emulator for the C128?

    On Feb 1, 7:36 pm, Andrew Owen wrote:
    > You can download it here:
    >
    > http://www.worldofspectrum.org/sincl.../versions.html


    Or indeed here:

    ftp://ftp.worldofspectrum.org/pub/si...4/c642spec.zip

    Which I posted a weel ago. ;-)

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