Chibi Akumas Episode 1: Invasion... For MSX2 and MSX2+V9990!

Hi keith56,

A very nice and very colourful game! I hope you don't mind I added it to my site: https://www.file-hunter.com/MSX/index.php?id=chibiakumas

For anyone interested, Amstrad CPC regular reviewer "NovaBug" did a short play-through with commentary of the Turbo-R +V9K version of this game

https://youtu.be/WFfwD1rvudU

Check it out!

On the regular MSX2 the Bullets and the gradient are done my accessing the VDP memory and writing the bytes straight to it,
the VDP's fill rate is the bottleneck on the MSX2 (hence why the MSX2+V9K is faster)

I also have a 'fastfill' for clearing areas of the screen - it will use the memory access to write blank bytes until the vdp is ready, then send the VDP FILL command to fill the rest while the CPU gets on with other things.

The V9K without the Turbo-R IS slower, but as the Turbo-R limits the OUT commands, I don't think that's the cause either - I think the Turbo-R version is faster just because the logic code can run more quickly

For the 'sprite bullets' of the V9K version on the MSX2, I'm not aware I'm doing anything that clever, the code is almost the same as the one in this tutorial...
https://www.youtube.com/edit?o=U&video_id=GNqLOg9jtmc
... the only difference is I use a custom interrupt handler, and I assume the Status reg S#2 is selected (so I can quickly check if the VDP is busy) wheras the firmware requires S#1 to be selected

Of course, the CPC was using the Z80's power to do all the sprite work (moving each byte of the sprites to screen memory), so on the MSX2 where the VDP is taking over that load, there is a lot of CPU power left over, so maybe it's just because the game core was built around having no CPU power to spare?

Even that i'm not speaking Japanese, this still sounds great!