SP-2-ZX81, the new ZX81-emulator for the 48K ZX Spectrum

[dr beep]

The only game I couldn't get to run though (neither with previous versions) is 81-tris and I can't see an obvious reason, seems like a "normal" 16k game to me...

81-tris, like my 1K hires games, has a special defined displaymethod.
It looks like an intrupt controlled game but the method is different from my CALCULUS MAZXIMUS.

We need to ask SALVACAM

I don't know how I can help you, I use z88dk to program, to paint the blocks of the pieces I use the SetBlock function (in ASM), for the rest, instructions, markers,... I use the printf function (from z88dk).

All my games have the code available on my website, it is in my signature

I suspected something like this.
I need to alter too much and at the cost of speed to add support for your game.
The compiler you use is using IY and that could give problems when an intrupt occurs and IY would have a different value than #4000
since during intrupt a systenvariable is checked with the value of IY.

[redgatemodels]

Hi,

very much a newbie here, but am I right in thinking that this can be made into a tape program that can be loaded into a Spectrum and then load ZX81 games into it?

I've got a couple of ZX81 titles from when I was a kid that I'd love to play again.

If this is the case, how is the tape made?

[dr beep]

Hi,

very much a newbie here, but am I right in thinking that this can be made into a tape program that can be loaded into a Spectrum and then load ZX81 games into it?

I've got a couple of ZX81 titles from when I was a kid that I'd love to play again.

If this is the case, how is the tape made?

You can download a TAP-file here
https://www.mediafire.com/file/8ppnz7lp ... 6.tap/file
and convert it to WAV with this
https://www.sinclairzxworld.com/viewtopic.php?t=3145

[dr beep]

Hi,

very much a newbie here, but am I right in thinking that this can be made into a tape program that can be loaded into a Spectrum and then load ZX81 games into it?

I've got a couple of ZX81 titles from when I was a kid that I'd love to play again.

If this is the case, how is the tape made?

When you can find the games on the net you can convert them too into a tap and then load them.
When your games are on tape you can best convert them to PC first and then do step above again.

[redgatemodels]

Hi,

very much a newbie here, but am I right in thinking that this can be made into a tape program that can be loaded into a Spectrum and then load ZX81 games into it?

I've got a couple of ZX81 titles from when I was a kid that I'd love to play again.

If this is the case, how is the tape made?

You can download a TAP-file here
https://www.mediafire.com/file/8ppnz7lp ... 6.tap/file
and convert it to WAV with this
https://www.sinclairzxworld.com/viewtopic.php?t=3145

Many thanks, I'll have a go once I get my Speccy fixed, it died last night

[chernandezba]

This is the official release of my NEW ZX81 EMULATOR for the 48K ZX Spectrum.
Fully software and much faster than my emulator from 1997.
The old emulator is also included.
https://www.mediafire.com/file/oiejfzmj ... X.zip/file

Awesome! I've just discovered this emulator, you did an amazing work! It's incredible how , according to your documentation, you have an emulation speed of 12.5% but I've tried Mazogs and it's playable! I'd say it's a bit less of half of the speed than on a real ZX81, I assume you get more speed by emulating the
display routines and avoiding all the NMI stuff from the ZX81.

Also I've debugged a bit your emulator and saw your mainprogram routine and look at how you emulate some opcodes, very interesting!

Just a question:

- Where can I find the last release? The mediafire zip has a tap file "2020 SP-2-ZX81.tap" but there's also another mediafire download, just the tap file "sp2zx81v216.tap" (which I assume this is the last one) . Where is the last release, with all files: emulator, source code, pdf, etc... ?

Maybe you could consider putting all this files on github...

Regards,
César

[dr beep]

This is the official release of my NEW ZX81 EMULATOR for the 48K ZX Spectrum.
Fully software and much faster than my emulator from 1997.
The old emulator is also included.
https://www.mediafire.com/file/oiejfzmj ... X.zip/file

Awesome! I've just discovered this emulator, you did an amazing work! It's incredible how , according to your documentation, you have an emulation speed of 12.5% but I've tried Mazogs and it's playable! I'd say it's a bit less of half of the speed than on a real ZX81, I assume you get more speed by emulating the
display routines and avoiding all the NMI stuff from the ZX81.

Also I've debugged a bit your emulator and saw your mainprogram routine and look at how you emulate some opcodes, very interesting!

Just a question:

- Where can I find the last release? The mediafire zip has a tap file "2020 SP-2-ZX81.tap" but there's also another mediafire download, just the tap file "sp2zx81v216.tap" (which I assume this is the last one) . Where is the last release, with all files: emulator, source code, pdf, etc... ?

Maybe you could consider putting all this files on github...

Regards,
César

I will make a version of sources manual etc for 2.16, which is the latest version.

speed is gained by skipping screenupdates which you can set in the menu.
Another method to win speed was by "translating" frequent used ROM routines into routines that can run without checking relocated code. These routines are triggered by non existing ED code or IX code.

Another trick that works on game that don't use full screen is that empty lines are skipped when a check in the menu is done.

[dr beep]

Awesome! I've just discovered this emulator, you did an amazing work! It's incredible how , according to your documentation, you have an emulation speed of 12.5% but I've tried Mazogs and it's playable! I'd say it's a bit less of half of the speed than on a real ZX81, I assume you get more speed by emulating the
display routines and avoiding all the NMI stuff from the ZX81.

MAZOGS plays even better on SP-2-ZX80

Also I've debugged a bit your emulator and saw your mainprogram routine and look at how you emulate some opcodes, very interesting!

The mainroutine is also used in an emulator on the SAM-coupe.

Maybe you could consider putting all this files on github...

Regards,
César

https://github.com/zx81coder
but sofar only the smallest model to code games on the ZX81.

[chernandezba]

Another method to win speed was by "translating" frequent used ROM routines into routines that can run without checking relocated code. These routines are triggered by non existing ED code or IX code.

That's very clever!

[dr beep]

After finding out the QUARACTERDISPLAY-method on the ZX81 I was thinking to add this to my emulator.

PROBLEMS:
1) Memory to add this option is really tight.
2) How to simulate this behaviour?
3) The emulation will slow down.

So I have started to add this option. First thing I did was to increase emulation speed.
Second step was to create room.

This version is some percent faster than 2.16 and room is created.
So even when I won't succeed in adding QUARACTERDISPLAY the emulator has sped up a bit.

I REMOVED V217. There is a bug when returning from the menu.
I will add a new version later.....