Sinclair ZX80 / ZX81 / Z88 Forums

Hello Antonio, I have released recently something similar, ... I read about it in your "Unkatris" topic , thank you for sharing of your great work. Also thank you for sharing your work. Using your excellent loader and these optimisations above, there are 164 :!: bytes free space to make it smarter....

Hello zsolt I have released recently something similar, source code is here: http://sourceforge.net/p/emuscriptoria/code/HEAD/tree/chess/ An exact disassembly is in chess.asm, and a 148 bytes optimization in nchess.asm. Use it in your code if you see it interesting, probably you can cross the optimi...

I did not know that somebody is reading my blog;-) In your schematic is lot bugs. 1.) Bad regulator (must use 3.3V version) I copy this from your schematics. 2.) Bad RC circuit (Resistor to Power Capacitor to Ground) 3.) Diode is reversed. Not a bug. I've inverted the signal, so I need interchange ...

Hello The problem is the .P format, it's not concatenable. For example in Spectrum there is equivalent .TAP file for standard loading, that format has the filename included and you can join without problems two .TAP files. But I have released .TZX and .WAV files that should work on real hardware. Th...

You explained perfectly the loader. The "99" display number is because there is the FRAMES variable and is decremented, but now I think that a simple "9" also works. The last $28 belongs to the 9 bytes of the game. And the most important, the SP at $43FE will point 2 bytes below the top of the memor...

Cool, congrats! Is it possible to take a look to your loader part? (the 1st block) - it is very interesting . :o Regards, Zsolt PS: The 1kchess? It was my project for this summer :D , and finally I got similar results The first block is very simple. I have deleted the source that generates the arra...

I am trying to replicate the Pokemon ZX8-CCB board with throw hole components. There is another board also based in Pokemon ZX8-CCB http://www.oldcomp.cz/viewtopic.php?f=88&t=1809 But it has not color inversor. My idea is something like this: backporch.png But I don't know if this circuit would work...

A gameplay:

https://www.youtube.com/watch?v=Ex91OwHMVog

Wow. It's awesome. Good optimization. You can eliminate the unknowed B by changing the first instruction with "defb 1, N" and with A!=13. That loads B with $10 (opcode of djnz).

Your calculations are wrong in this case. DJNZ uses only register B. So maximum execution for inner loop is 256*256 = 65536. If you count clock cylces then DJNZ has 13 clock cycles if jumping, 8 if not. So the inner loop is 3323 clock cycles plus 21 cycles for PUSH/POP = 3344 cycles = 1ms for 308ns...