initial cpu structure :thonk:

Signed-off-by: Amneesh Singh <natto@weirdnatto.in>

src/cpu/utility.hh

@@ -0,0 +1,17 @@
+#pragma once
+
+enum class Mode {
+    /* M[4:0] in PSR */
+    User       = 0b10000,
+    Fiq        = 0b10001,
+    Irq        = 0b10010,
+    Supervisor = 0b10011,
+    Abort      = 0b10111,
+    Undefined  = 0b11011,
+    System     = 0b11111,
+};
+
+enum class State {
+    Arm   = 0,
+    Thumb = 1
+};