feat(mm): initial mm work

src/mm/root.zig

@@ -0,0 +1,36 @@
+pub const private = @import("private.zig");
+
+const b = @import("base");
+const std = @import("std");
+
+pub const page_size = 4096;
+
+pub const init = private.init.init;
+
+// 16 TB of maximum physical memory.
+// This should be fine on consumer hardware for at least a decade :^)
+pub const Pfn = u32;
+
+pub const Page = struct {
+    // Fields used when the page is free.
+    next_pfn: Pfn,
+    batch_next: Pfn,
+    batch_count: u8,
+};
+
+pub const MapFlags = packed struct {
+    read: bool = true,
+    write: bool = false,
+    user: bool = false,
+    execute: bool = false,
+    global: bool = false,
+    write_through: bool = false,
+    cache_disable: bool = false,
+};
+
+pub fn page_to_pfn(addr: usize) Pfn {
+    return @intCast(addr >> 12);
+}
+
+pub const p2v = private.impl.phys_to_virt;
+pub const v2p = private.impl.virt_to_phys;