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> As it would turn out, the Game Boy Advance has quite a bit of “weird memory” that you have to work around in weird ways. I know that this is a long shot, but

• NobodyNada 2y ago
  I'm not a compiler dev and I don't know Zig, but I can think of a couple of things that make this tricky: - The compiler doesn't typically know anything about memory address ranges; that's the linker's business. - Even if you taught the compiler about memory address ranges, the compiler often won't know what address ranges a pointer could point to at runtime. For instance, suppose you declare a function that takes a pointer as its parameter; and then maybe elsewhere in your code you call it with pointers to various address ranges. What's the compiler supposed to do, check the pointer value at runtime and branch based on its address range? That's certainly not good for performance or code size. So we clearly need some way to "color" the pointer type itself as belonging to a specific address range -- a function needs to be able to declare what color of memory it wants to operate on, and it should be an error to pass a wrong-colored pointer to a function. Except you can already do this in programming languages today! Create a wrapper type representing a pointer to a specific type of memory (something like 'struct VramPtr(*mut u32)' in Rust), and define read and write functions that issue volatile writes of the correct type (or even inline assembly if you need some specific instruction that volatile doesn't guarantee).