feat(loader, kernel): impl part of loader and initialize kernel structure

arch/x86_64/processor.zig

@@ -0,0 +1,44 @@
+pub fn readCr2() u64 {
+    return asm volatile (
+        \\ mov %cr2, %rax
+        : [ret] "={rax}" (-> u64),
+        :
+        : .{});
+}
+
+pub fn readCr3() u64 {
+    return asm volatile (
+        \\ mov %cr3, %rax
+        : [ret] "={rax}" (-> u64),
+        :
+        : .{});
+}
+
+pub const PrivilegeLevel = enum(u4) {
+    Kernel = 0,
+    User = 3,
+};
+
+pub const PtRegs = struct {
+    r15: usize,
+    r14: usize,
+    r13: usize,
+    r12: usize,
+    bp: usize,
+    bx: usize,
+    r11: usize,
+    r10: usize,
+    r9: usize,
+    r8: usize,
+    ax: usize,
+    cx: usize,
+    dx: usize,
+    si: usize,
+    di: usize,
+    code: usize,
+    ip: usize,
+    cs: usize,
+    flags: usize,
+    sp: usize,
+    ss: usize,
+};