I'm trying to extract the memory/bus interface, and pass it in at
the start of each cycle instead of having the BusPort permanently
embedded, which will allow migrating to emulator-hal.
The functional way would be argument drilling; passing an extra argument
to each function in the entire execution core. The problem is that it's
messy, so a solution that is still functional is to implement all of the
execution logic on a newtype that contains a reference to the mutable
state and the owned cycle data, and at the end of the cycle, decompose
the M68kCycleGuard that holds the reference, and keep the cycle data for
debugging purposes.
The debug loop that reads a command and does something is part of the
frontend's main loop, so that it can potentially update, even though
it doesn't actually work for minifb because the command input is a
blocking call. It's also not implemented in the pixels frontend.
At some point I'll make a web frontend.
AddressRepeater now takes the range it should repeat over, which only
really affects its reported size.
AddressAdapter is now AddressRightShifter, which is literally the operation
it performs, where the input is still the bits to shift the address right by
I wanted to make this a bit more modular, so it's easier in theory to
write external crates that can reuse bits, and selectively compile in
bits, such as adding new systems or new cpu implementations
