ZX81 emulator for iOS

[kpalser]

Hi all,

Apple approved my ZX81 emulator for iOS today: http://zx81-ios.weebly.com

Consider it just the first step of an app that I hope to extend with more functionality, software titles and eventually an interview section. Currently I'm working on a more game friendly version of the virtual keyboard in the form of a game pad. Currently game play is frustrated on smaller iOS devices due to the simulated key size.

There are only a few programs bundled with the first version of this app. Apple is quite strict regarding running software through its apps. Hence, I shall never be allowed to add functionality to load your favourite external P files or via recordings through the microphone etc. All the ZX81 software needs to be embedded in the app package submitted to Apple. If you have rights to ZX81 software and would like to see it included in future versions of the app then let me know.

Enjoy,
Kevin

[Lardo Boffin]

Hi all,

Apple approved my ZX81 emulator for iOS today: http://zx81-ios.weebly.com

Consider it just the first step of an app that I hope to extend with more functionality, software titles and eventually an interview section. Currently I'm working on a more game friendly version of the virtual keyboard in the form of a game pad. Currently game play is frustrated on smaller iOS devices due to the simulated key size.

There are only a few programs bundled with the first version of this app. Apple is quite strict regarding running software through its apps. Hence, I shall never be allowed to add functionality to load your favourite external P files or via recordings through the microphone etc. All the ZX81 software needs to be embedded in the app package submitted to Apple. If you have rights to ZX81 software and would like to see it included in future versions of the app then let me know.

Enjoy,
Kevin

I downloaded that before I finished reading past the first sentence! Awesome stuff!

I was about to ask about loading external files but you beat me to it. Knowing Apple as I do I'm not surprised they block additional files.

[Lardo Boffin]

Actually how about the ability to save programs you type in?

I'm not sure if there is a limit on the size of local storage data but ZX81 progs are not that large.

Also you could save data in SQLite, one file per record in a fairly simple table. We use SQLite extensively at work in our iOS app. It's pretty good.

Lardo

[kpalser]

Actually how about the ability to save programs you type in?

I'll give it some thought. There's certainly nothing in the Apple developer guide prohibiting saving your own programs. Probably more along the lines of a complete memory capture of the 16k of address space plus the registers rather than adding conditional traps to detect the ROM save routine. I spent so long trying to optimise the code that I'm loathed to add anything that might slow down even slightly the Z80 execution loop. Hence the raw memory dump route... Could also work on the save functionality to create audio output to be saved for loading on a real ZX81.

[kpalser]

I've just had to resubmit again to Apple because the Software Farm game in-app purchases were not correctly linked in the first submission request even though the files and app logic are correct... It will take about 4 days to get this straightened out with Apple. In the meantime I hope there aren't any negative reviews. Tempted to take it temporarily off the store.

[chernandezba]

Great job!

Tried on iPad and works perfect

[Paul]

Tried on iPhone 5 and couldn't install.
It's not compatible.

[kpalser]

Tried on iPhone 5 and couldn't install. It's not compatible

Consider this the stock answer ( also see the FAQ in http://zx81-ios.weebly.com ):

The irony of not supporting older devices for an emulator of an old computer is not lost on the developer.

The short answer: No plans to support anything below the 64bit processor of an iPhone 5S on the app store.

The longer answer: Apple does not provide many developer options to specify which devices are not supported. So before iOS 10 the only way to stop iPhone 4S and below users downloading the app was to add the minimum requirement of a 64bit processor. When iOS 10 came out this was less of a problem, i.e. iPhone 5/5c and above. However, emulators tend to be heavy on the processor and drain the battery very quickly on slower devices. It would be technically possible to compile a version for the iPhone 5 but it saves a lot of headaches to just look to the future.

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@Paul, if you're really keen to see it on your iPhone 5 send me your UDID and I'll build you an adhoc version to test and send feed back.

[1024MAK]

Have just downloaded it to an iPad mini. Great work

Where's the like button when you need it...

Mark

[1024MAK]

One small question, I know a real ZX81 does not have a reset button, but is there a reset available in your emulator?

Mark