Shop OBEX P1 Docs P2 Docs Learn Events
PASM Quick Refresh, and ZiCog? — Parallax Forums

PASM Quick Refresh, and ZiCog?

davidsaundersdavidsaunders Posts: 1,559
edited 2017-02-27 20:03 in Propeller 1
I have not been doing very much with the Propeller lately, so looking for a quick refresh in PASM. Just something quicker than the v1.2 Propeller manual, a quick ref of some form that includes the registers, timers, and instruction quick ref.

Also looking for ZiCog, Heaters single core Z80 emulator. Does anyone know where it dissapeared to?

I am getting back to the propeller for the dual reasons of using it as a periprerial for the Raspberry Pi, and doing a good emulation of the Game Boy Color.

On the Raspberry Pi attachment, it will be used to control steppers, and provide a few other extras.

The Game Boy Color emulation is to provide an alternative to a real Game Boy Color, in a near identical case with a reflective LCD color screen.

Comments

  • Also looking for ZiCog, Heaters single core Z80 emulator. Does anyone know where it dissapeared to?
    ZiCog a Zilog Z80 emulator in 1 Cog
  • Heater.Heater. Posts: 21,230
    Hi David,

    I don't know. The Propeller manual is all I ever used. Apart from lot's of good advice on this forum of course :)

    ZiCog is still here: http://forums.parallax.com/discussion/110804/zicog-a-zilog-z80-emulator-in-1-cog/p1

    Sorry I have not worked on that for a long time. It was stalled by life going on and the expectation of moving it to the P2, which is still not possible.

    You may also be interested in forum member PullMoll's Z80 emulator, qz80. Google can find it for you.

    You should perhaps ask about Raspberry Pi attachment problems and Game Boy emulation problems in separate threads to avoid confusion.

  • Heater. wrote: »
    You may also be interested in forum member PullMoll's Z80 emulator, qz80. Google can find it for you.
    qZ80 - the third shot
  • Heater. wrote: »
    Hi David,

    I don't know. The Propeller manual is all I ever used. Apart from lot's of good advice on this forum of course :)

    ZiCog is still here: http://forums.parallax.com/discussion/110804/zicog-a-zilog-z80-emulator-in-1-cog/p1

    Sorry I have not worked on that for a long time. It was stalled by life going on and the expectation of moving it to the P2, which is still not possible.

    You may also be interested in forum member PullMoll's Z80 emulator, qz80. Google can find it for you.

    You should perhaps ask about Raspberry Pi attachment problems and Game Boy emulation problems in separate threads to avoid confusion.

    Yes I probably should seperate these questions. As most of the answers have been related to Game Boy Emulation, lets run with that in this thread for now.

  • The most difficult part of Game Boy Color emulation is going to be the PPU, do to the limited time to sort the list of "Objects" (sprites), , do up to 10 compares per pixel (if that many overlap with the same X position, and only the last one is non-transparent at that pixel).

    Thanks to Heater the CPU should be fairly easy, as the Game Boy CPU is a subset of the Z80, with a different Flags layout, and a few minor extras.
  • Heater.Heater. Posts: 21,230
    There is one major outstanding problem with the ZiCog emulator. It does not support the register bank switching instructions, EX, EXX or whatever they are called.

    Turns out they were not used by the CP/M operating system or any applications for it so I did not have any incentive to implement them.

    Also some bit manipulation operations that such software never used.

    I believe qz80 does it all.

    I know know nothing of the Game Boy, but I have heard it has some extra instructions and differences from the Z80. So it sounds like you have some work to do no matter what.
  • Well the Game Boy CPU is a Z80 without the extra registers (only has the 8080 registers), a different layout of the Flags register, and having only some of the CB bank instructions, also missing a few things from the 8080, and with a couple extra instructions.

    As such the ZiCore is a near perfect starting point.
  • Heater.Heater. Posts: 21,230
    Sounds promising.

    I worry that any little change in the status register, means changing every opcode handler to accommodate that.

    Adding a few instructions or removing some is easy enough I guess.
  • Cluso99Cluso99 Posts: 18,069
    Some links are in my signature below.
  • Many thanks. I would say that gives me a starting point.
Sign In or Register to comment.