tehKaiN
commented
1 year ago Well, up to this point noone tested ACE on CDTV, so it's kinda expected that something went wrong.
I'd approach it differently - figure out how to disable/enable CD drive DMA (?) and turn it off when OS gets disabled.
Polling keyboard is kinda risky - keyboard controller queues keypresses to be sent to CIA via serial interface and it sends another keypress only if previous one is successfully read, as signalized by specific handshake. If you won't read them in time, the queue will overflow, in which case the keyboard controller will reset the Amiga. IIRC the queue is 8-keypess long, should be very difficult to trigger overflow at the span of a single frame, but I think not impossible on keyboard-heavy multiplayer game.
Re leaving OS functional - yes, this should be an option, but only as a choice, because OS tends to eat away random amount of frame time while it's alive.
I'll try to dig up some docs on how CDTV works and how to handle its hardware properly.
rveilleux
While working on my game prototype, I might have discovered that when testing on a CDTV (in winUAE), the ACE engine doesn't work: I've tested using germz ADF from the game's website to make sure it wasn't something specific (since I modified the engine on a few places). I discovered that int2Handler, which handles the INTF_PORTS interrupts, for CIA A (CIAICRF_SERIAL for keyboard, CIAICRB_TIMER_A for timers), that apparently the CDTV hardware also uses that interrupt for the CD. (When debugging it, it appears as if the int2Handler is triggered continuously, which freezes the ACE engine/game.).
I was able to 'fix' it on my customized ACE engine by disabling INTF_PORTS interrupts and using VERTB to "poll" keyboard. Probably not an ideal solution since perhaps I could miss some keypresses.
I just wanted to at least inform you about the situation. The real proper way to handle it is probably to have an IntServer and let OS handle the CD interrupt instead of masking them.