A port from spectrum to arcade :-). Since its a arcade board, a credit function could been fun to add.... Hehe.
Of course its seen Taito L System was not random choiced, which is pretty much similar to Spectrum, so im thinks its was easier to code for (even the graphics of course is a bit different).
I've forgotten to write it in the documentation, but the "insert credit" function is
actually used as "quit and return to menu".
Yes, this system wasn't chosen completely randomly. One
of the reasons is that it's using the Z80 processor - and that's what I can code.
But with hardware sprites and scrolling it is used very differently from a Spectrum. One very different thing - you don't have direct access to the screen area...you can't just draw random dots or a line or whatever. Only sprites and tiles can be drawn - nothing else, so you have to do things differently.
And the hardware has some weird peculiarities, like you can't use indexed adressing in banked RAM...and you can't write 16-bit values to banked RAM either, so if you want to draw a sprite you have
to write the Xcoord as two separate 8-bit values. Weird.