MEGA65 wants you!

Es gibt 47 Antworten in diesem Thema, welches 9.302 mal aufgerufen wurde. Der letzte Beitrag (24. Januar 2022 um 15:19) ist von deft.

  • Bitte melde dich an, um diesen Link zu sehen.: It has nothing to do with the C128.

    In the C65, the 4510 was designed to handle a 1MB address space via bank switching: although it can access only 64K directly, but its two 32K segments can be mapped to anywhere within the 1MB individually (by the processor itself). The space contains both RAM and ROM which is 256K in the prototype machines (128K RAM + 128K ROM) and above which an optional 512K RAM expansion was planned.

    The DMAgic is more capable than the REU and its address space also involves the system RAM (so the first 1MB is common). It can handle up to 8MB by design. (So thus it is more similar to the DMA controller in the C64DTV which has got 2MB built in that contains the first 64K, too.)

    In the MEGA65, both the mapper and the DMAgic are further expanded by Paul to work even up to a 32-bit address space.

  • Hi Paul,

    Thank you for your answer.
    After reading some documents I thought the C65 contains:
    - several bitplanes (like Amiga has). like 4 bitplanes combine 16 colours from a palette.
    I understand you put in the Mega65 a different mode: 1 byte per pixel?

    For me the old one is okay, using tables and fast code give magic :smile:
    Perhaps your additions gives new possibilities.

    - Did you add a multiply routine ?
    Can be useful for 16 bit. However I coded a multiplier, 7 x 7 bit / 256 on 6502
    that take same or less clock ticks than Amiga/68000 does with MULU/MULS function.
    It's 14 lines of code and a short 8 bit sine table. I don't know if this trick/method already is used, but it just came up in mind and I made it.

    - The DMAgic is very useful I think for cleaning and copying bitplanes, etc.
    The addition of proportions and a counter for scaling (I understand?) is also nice!

    - Also the addition of 16 bit DA converters is welcome I think!

    - But how do you see all the additions considering the original c65 ?
    Mega 65 programs will not be compatible anymore on c65 ?
    Or is there an original c65 mode :wink:

    - I was thinking of several things. Perhaps making and sharing some fast open-source routines, like division, sin, arcsin, sqrt, etc. (who contributes?)
    And simple routines for drawing lines, filled planes by coordinates,etc.

    For now I want to finish programming some small 3d objects on the C64 (sorry I use Vice with original speed). It will be 50 fps or at least 25 fps I guess, rendering small +/- 6-10 plane objects in real time. If it's ready I can show you. Nice work for the lazy sundays at the moment.

    Sure the objects can be a lot bigger and complicated on the Mega65

    Love 8 bit,

    Urias (Holland)

  • Hello Urias,

    Thanks for your reply (and also for your email). A few answers below:

    1. The MEGA65 supports almost all C65 modes and features, including the bitplanes, although in my view, the C65's bitplanes are too limited to be really useful for anything, primarily because scrolling them requires moving a lot of memory around.

    2. The MEGA65 supports new enhanced text modes, that includes both 16 colour 16x8 and 256 colour 8x8 character tiles. For both of those which require 64 bytes per character, you can have up to 2,048 characters, so it is quite easy to make large scrolling playfields this way. This will be great for platformers and similar games, and also helps save a LOT of RAM, when you tend to have large empty or repetitive parts of the screen. You can even use the hardware character kerning feature to allow characters to not be forced to the 8 pixel horizontal columns, giving some extra flexibility.

    3. There is a hardware 25x18 bit multiplier that gives a 48 bit output. This takes only a few cycles. Basically you don't have to wait at 40MHz, because it is finished before you can read the first result byte. There will also be a "hardware spreadsheet" that can be used to implement simple equations, without having to copy operands around the place, making things potentially much faster -- faster even than many 32 bit processors can calculate such equations, due to the removal of the need to shuffle values around the place.

    4. There is a C64 mode, and a C65 mode, as well as the new MEGA65 features.

    5. Yes, a library of routines for doing interesting things on the MEGA65 and/or C65 would be very interesting and useful. Bonus points if you make the routines with CC65 wrappers, so that the library can also be used from C.

    6. The 3D renderer sounds very nice, and I would certainly like to see it when you are ready to share it. Yes, it will be able to perform MUCH faster on the MEGA65 for various reasons. I would be very happy to help you optimise it for the MEGA65, so that we can show off what the MEGA65 is capable of in this area.

    Keep up the good work!

    Paul.

  • Thank you for your Answer. I admire your ability to (re)make a whole computer & more.
    Incredible & amazing job!

    1) 2) A new graphic mode is a Nice addition! However, in Some cases bitplane mode ‘ll be useful, I think. For example; one bitplane is less data. (where only using main CPU). Scrolling memory scrolls 8 bits at a time, one instruction. Tricks can be Made. But I agree, when using a coprocessor and more memory; more possibilities!
    3) Very Nice addition! I am getting tired of programming multiply routines, take lots of code & time.
    4) beautiful, multiple modes!
    5) 6)
    Still programming. Now polygon algorithm almost finished. Took me days to optimise.
    It draws a simple 4 point polygon, filled, single selectable colour.
    Very small polygon of 40 pixels high takes approxemetly 100 rasterlines of time.
    Next step is 3D calculating an object. So f.e. a very small cube (about 1 sprite) ‘ll be possible at 50 fps. (C64, vice normal speed)

  • Our group can't wait to program games for the mega65 in 800x600, 256 color, up to 1 meg, in 64k banks. It will be a real pleasure transfering our games, and utility software into this renewed system, if its 6502 it will be easy, and if the cartridge port works the same as a 1750 or 1764, were in business.

    President JAH, Excalibur 64/Amiga user group wisconsin, via Compute! Magazine

    looking for an Amiga PAWS if any one knows of its existance

    Bitte melde dich an, um diesen Link zu sehen.

  • Hi Jody,

    This sounds great.

    The cartridge port works very similarly as for a C64, and most C64 cartridges will work. For expansion memory, the MEGA65 will have 8MB of ~10MHz expansion RAM in the final version, but in the meantime, there is 384KB of main memory, that the VIC-IV and CPU can both access, as well as being able to access the SD card at between 700KB/sec and 1.3MB/sec already.

    The CPU is an enhanced 6502, with memory banking commands, and also some instructions for directly accessing any byte of memory without having to change the memory bank layout, which helps keep code small and fast.

    Basically if you have questions, or need information, then poke us, and we will do our best to support you, as we are also excited about the prospect of MEGA65 games.

    Paul.

  • Hi all,

    I am currently looking for someone with Blender or similar rendering experience who might be able to render the MEGA65 box more beautifully than I can do it myself :)

    Anyone up for the challenge to support us (and have his images all over the web)?

    "VHDL schreiben ist wie in Mordor zu arbeiten. Es gibt viel Streben und viel Rauch, aber nur wenig Erfolg. Und Erfolg sieht meist schlimmer aus als Misserfolg" PGS 2019