Sinclair ZX80 / ZX81 / Z88 Forums

Isn't patching an option? First check if used ROM is altered. From documentation this should be done only for the DAA instruction. Is replacement of the ROM not enough? Just load that ROM instead of ZX81ROM. Does Dragon Lair use a specific hires method? WRX with 6K buffer and setting of IX only sho...

BTW, SAM2ZX81 supports also hires from WRX and even some more.
Display kicks in when uppermemory is called and displayed on screen, although slower than real ZX81.

Don't know about the speed of Xtricator and hires together.
Lowres can come close to real speed with some tricks, but hires??

Isn't patching an option? First check if used ROM is altered. From documentation this should be done only for the DAA instruction. Is replacement of the ROM not enough? Just load that ROM instead of ZX81ROM. Does Dragon Lair use a specific hires method? WRX with 6K buffer and setting of IX only shou...

Finetuning the last steps.

Shot left and right working, but calculation of Y-height is a problem to figure out.
It will be a small adjustment, will find it out.
Memory left: 0 bytes!!!!!

Thanks a lot for your time dr.beep explaining all these, the info so far is quite illuminating! :) I just thought that it would be much simpler for a pure software cycle-exact emulation between the two machines... :roll: The interfaces from Paul Farrow do not emulate, but run the original code on o...

Loaded cannon was shown and fired after input from angle and speed. Now shown before input, indicating who's turn it is. Just a few things to do, set correct start, read next value in shooting loop, test out of screen, test hit restart game. All can be done in max 10 bytes, I think. 28 bytes left (a...

Basic movement added.
Next to do is following the sinusloop.
Cannon is moving on the screen.

I even shortened the routine from 27 to 26, a dx movement is always needed so testing reached coordinates could be done later.

Still 33 bytes free and possible 20 in altered display.
Almost....

Wow, thank you for the answers!! I already know about the existing emulators, but none of them seems to be a "complete solution", at least WITHOUT the addition of extra hardware and on a plain 48k machine... of course I am not a coder and I can't know all the difficulties that occur during programm...

Hope this will do. Emulation on a ZX Spectrum Let me first state 3 base rules for an emulator: 1) memory must be enough for emulated machine and emulatorcode. 2) screenresolution must be higher or equal to emulated machine 3) CPU-speed must be about 10x the emulated machine The first 2 rules apply t...

Manual about the ZX81 emulator:

Press 1 and 0 for menu.
Possible old version on WoS

Edit: WoS version is final published version.
(Unpublished altered version with some hires emulation never released, nor will be)