Spectrum Computing

I just noticed I made a small mistake in my previous post. Here it is, just in case somebody stumbles on this in the future:

LDI() should be

ALSO, while I'm here: I know I've seen some kind of test program, with a huge matrix of characters on screen, designed to test every possible input. Blue text, cyan screen, with a keyboard layout on top, and at least three joystick protocols below (IN 31, IN 55 and Fuller) - maybe more, such as the...

I think that's a result of the floating bus. Reading from an unattached port will return whatever data happens to be on the bus at that time.
You can find more info about it here: https://sinclair.wiki.zxnet.co.uk/wiki/Floating_bus

Cheers!

Yes, it does require a 128k machine. More details can be found here: http://www.svgalib.org/rus/1k4kgames.html. From the scrolly-stack\scrolly.txt , inside the zip available on that page: Scrolly Stack - 4k entry for 2003 Minigame Compo Public domain by Russell Marks [...] for 128k Spectrum (only) N...

XoRRoX wrote: ↑Sat Mar 04, 2023 6:06 pm Where did you get this info?

That info was provided by Woody himself, on the ZX Spectrum discord.

Cheers!

1024MAK wrote: ↑Thu Mar 02, 2023 1:45 am Stole my thunder…

Sorry about that @1024MAK .

Cheers!

Hi catmeows , SkoolKid I'm curious, what exactly Issue 2 emulation means ? What is the difference from other issues ? Now to find out what the "Issue 2 keyboard" option in Fuse actually does... From the Spectrum FAQ, here or here : The ULA chip uses the same pin (28) for all of the MIC soc...

Madhatter seems to require an Issue 2 machine. Try enabling Issue 2 emulation and it should work .

Cheers!

Slider wrote: ↑Thu Feb 16, 2023 9:14 pm Yes, 128k only, because AY music and interlevel screens are located in 128k pages

thanks for the update @Slider!

the 2023 edition doesn't seem to be working on the 48k . it just resets after loading completes.

Hello SkoolKid , I'm not sure if this is what you are looking for but here are a couple of links that might shed some more light on how flags are affected in block instructions: https://github.com/hoglet67/Z80Decoder/wiki/Undocumented-Flags https://github.com/MrKWatkins/ZXSpectrumNextTests/tree/deve...

Hello @Zoran ,

I played a bit with Swan. I like it . +1 for Pascal .
The sound lagging, mentioned by @TheMartian, reproduced during my testing too.

I had a similar issue at some point. In my case it was caused by an audio buffer being saturated too quickly. Maybe it helps.

Great work!

Thanks AndyC :D . This little project turned out to be more addictive than I would have thought. It is, however, also very satisfying :) . Right now I am enjoying the "freshly baked" border stripes. I decided that I'll always paint the borders on the fly / cycle based , no matter which one...

Hi everybody, I'm back with a small update on this matter. Maybe it will be useful to some other beginner emulator developer, like myself :) . Halfway through the implementation I realized that even though I am now doing cycle based / on the fly screen reading / decoding , there will be games that w...

spider wrote: ↑Wed Aug 10, 2022 8:31 pm Ah I had no idea it was your own emulator!

Much respect as said for "writing your own"

Much appreciated!

Cheers

Hi @geecab , @Einar Saukas , @AndyC

Thanks for pointing me to the right direction .
I did some quick tests and I can confirm that you are indeed correct!


@geecab

geecab wrote: ↑Tue Aug 09, 2022 10:01 pm Respect to you writing your own emulator

Thank you for your kind words. I appreciate it

Cheers!

Hi spider I don't think it would be an emulator issue. Which emulator are you using ? And have you tried it in another one ? :) I've actually developed my own ZX Spectrum 48k emulator. I should have mentioned that in my first post. So, in this case there are some chances that I might have implemente...

Hi everybody, I finally had some time to play a bit more with my emulator (ZX Spectrum 48k) and I am back with yet another question :) . There's no surprise that Arkanoid is not wkoring on it, since I do not have any floating bus support. However, I thought I should give a try to Arkanoid - The hit ...

Small unsolicited feedback :
I noticed that the missiles won't cause any damage to the ground buildings and the bombs won't damage the planes.
I think it would be a bit more realistic if they would cause some damage .

What do you think?

Cheers!

This is all great info! Thanks for sharing!

Maybe we could have a sticky page in the Emulators section, where more experienced emulator developers could share info with newbies like myself.
Stuff like: tips and tricks, common pitfalls, different approaches, etc .

Hi TheMartian , This is exactly what I was looking for. Thank you! Your information is priceless! If only I would have seen it sooner. It would have saved me long hours of browsing through very old forum posts :D. I realize now just how important timing is :P. Here's what happened: Yesterday I told ...

@the.beginner Really like this thread. :) Please keep us updated with your emulator development. I can't help with sound emulation, but I can tell you that almost all authors of the most accurate Spectrum emulators are members of this forum. They may not all be active right now, but if you're looki...

scoppack I was looking at that code and wondering WTF, I didn't recognise it at all!! I tracked it down from the cpl command and it is from the Music Box Player Engine. It was a straight 'save as asm' from the program Beepola. It may help, or not. Mystery solved :D. Btw: that tune is very catchy. I...

Back with some updates on this. Maybe it will be useful to somebody in the future :) I'm still not sure what exactly the previously presented 8bitTris routine does, other than apparently acting as some sort of counter. However, using the debugger, I managed to understand what causes the ROM write at...

I'm not yet sure if there is something else, but for starters, there is definitely something wrong on my side with my "debugger". Even though the emulator executes that loop, at some point, somewhere, somehow the debugger fails to record the proper instruction being executed and it records...