cr1901 wrote:
Does anyone familiar with disassembling commercial games know whether any commercial games implemented a small heap manager in the VB RAM for maintaining data structures like event queues and possibly alternative stacks for interrupt processing and the like?
I don’t know, but I guess Red Alarm uses one because of its complexity (huge levels with moving parts and tons of enemies). Maybe Golf does too, although I’m not sure whether a renderer like that requires dynamic memory allocation.
As a follow up, does anyone have any experience writing a small heap manager for VB RAM?
Yes.
(Edit: you’re probably better off writing your own for your specific requirements, e.g. whether you need one that uses handles and can defragment the heap, like the classic Mac OS, or you want one that’s really fast but uses pointers directly, like DOS.)
If anyone has alternative ways of handling hardware events that don’t just resort to polling each time a hardware request is made, and are a bit more controlled than “worrying if a received interrupt will interfere with speed-critical game-logic processing or other fun race conditions” I’d love to hear your feedback.
Can you give some examples? You can often get away with polling, but yes, the code might be more elegant with interrupts.
And one last q: Is VB music typically controlled by the timer interrupt (i.e. wait until timer interrupt to change the playing sample)?
Yes, I think that’s how all commercial games do it. As usual, you can get away with calling a “do sounds” function in a VIP-synchronized loop, but if you want more precise timing, interrupts are the way to go, and you usually don’t have to worry about race conditions.