Add address deref, syntax, and deref sizes

Signed-off-by: Alek Ratzloff <alekratz@gmail.com>

examples/deadbeef.asm

@@ -1,31 +1,32 @@
-code $0x0 {
+.section data $0x1000 {
+    beef: .u16 $0xBEEF
+    ; TODO(syntax)
+    ; bytes: .u8 [
+    ;     $0xEF,
+    ;     $0xBE,
+    ;     $0xAD,
+    ;     $0xDE,
+    ; ]
+    .export beef
+}
+
+.section code $0x0 {
     main:
-        storeimm32 %r00, $0xDEAD
-        storeimm64 %r01, $16
-
-        shl %r00, %r01
-
-        storeimm32 %r01, $0xBEEF
-        or %r00, %r01
-
-        storeimm64 %r01, $0xDEADBEEF
-
-        cmpeq %r00, %r01
-        storeimm32 %r00, failure
-        storeimm64 %r01, ok
-
-        jz %r00
-
-        jmp %r01
-
-    failure:
-        storeimm32 %status, $1
-
-    ok: halt
-
+        mov %r0, $0xDEAD
+        shl %r0, $16
+        ; move 32 bits at 'beef' to %r01
+        ; TODO(syntax)
+        mov %r1, (beef)u32
+        or %r0, %r01
+        cmpeq %r0, $0xDEADBEEF
+        ; jump to the address 'end'
+        jz end
+        mov %status, $1
+    end:
+        halt
     .export main
 }
 
-meta {
+.meta {
     entry: main
 }