Lilly's Saga - The Stones of Evergreen

To be honest, I do not understand a word!

@Bengalack

Sorry for the delay to reply. RealLife (TM) is consuming all my free time lately.

It seems that the problem is solved. (or never really happened)

Would you anyway still be interested in the explanation? (maybe for future projects, joyMega support or to ignore other devices, like the touchpad or paddles)?

Is this issue still present with the latest openMSX development build?

Seems like the overview from https://www.msx.org/wiki/MSX-HID#Fingerprints_of_MSX_devices is what is happening when using openmsx. A mouse connected will, according to the page, and when no movement is happening, send 0000 as the four lowest bits from PSG reg #14. This means that Right, Left, Down and Up, is pressed.

My code flips these bits, and a bit that is set means pressed.

My code checks the bits in this order: JOY_BIT_TRG_A, JOY_BIT_TRG_B, JOY_BIT_UP, JOY_BIT_DOWN, JOY_BIT_LEFT, JOY_BIT_RIGHT

Furthermore, in my code when the bits are checked, will returns as soon as one set bit is found, and in our case, the first found is: JOY_BIT_UP. No other keypresses are "getting through" because of this return.

Run the game without mouse plugged and you will get the exact same behaviour if you just hold the UP key while on the title screen. Pressing down will not help or pressing space will not do anything at this point.

If you enter "plug joystickporta mouse", when in the game, you will see Lilly go left (and no cursor keys or space will work). When inside the game, the code is a bit different, and I check for vertical keypresses first and THEN horisontal, as keys can be combined. If Lilly is placed on normal ground you will not see her move up nor down (but UP will get "marked as pressed i the code"), but horisontally LEFT is check before RIGHT, so Lilly is moving left.

Not sure why openmsx sends the signals (ie. value of PSG reg #14) as described on the aforementioned page when a real MSX does not.

Well, one can mask the shaky borders with sprites, but that'll cost you two sprites per row - and probably a number of sprite-splts. And in a game like Chuka Taisen you'd rather want some extra sprite-bullets or sprite-enemies on screen.