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f18a 60 rows, 80 columns mode showing Stevie


retroclouds
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Here's a thing I've been playing with, and thought about putting it in a separate thread.


With the help of @Asmusr I tweaked the f18a emulation in my local clone of js99er, so that it can now run in 60 rows, 80 columns mode.

The idea was to see how I need to setup VDP memory to get stevie running in 60 rows, 80 columns mode and do refactoring for the different video modes (24x80, 30x80, 60x80, ...)


This is still a work-in-progress and will never be officially released, but it does prove that it's doable.

As a starting point I took the stevie build I made for classic99 where I use a character cursor instead of a sprite cursor.

(Sprite cursor is possible, but will only get halfway the screen, due to 1-byte for Y in the sprite attribute table, so of no real use here)

 

Anyway, the build for classic99 was also a hack, because I refresh the frame buffer each time the cursor blinks.

That clearly shows here, because I'm dumping quite a bit of data to the VDP and it gets a bit slow.

So, next thing to do for me is to get that cursor routine a bit smarter.

 

You never know, maybe the f18a mk2 will support a 60x80 mode.

I'm still wondering if it'd be doable on the f18a mk1 with a firmware update, but I think Matthew said it won't work because of VHDL already being chuck-full.

16K of VDP memory is enough though, as my demo shows.

 

Enjoy the demo (VDP corruption at the end when turning on the ruler., but that's part of the fun. I still need to fix some things in stevie).

 

 

 

 

 

 

 

 

 

 

Edited by retroclouds
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