* The ps2tek documentation states the memory map clearly [1].
It seems to have a similar architecture with the PSX, where
the main memory map (KUSEG0) is mirrored in multiple regions
(KUSEG1/KUSEG2) with different access patterns for each region.
For now we don't have to emulate all of them, just the main
memory map.

* Allocate the entire 512MB memory into an array and make a convenient
struct to abstract memory range operations.

[1] https://psi-rockin.github.io/ps2tek/#memorymap