1 files changed, 22 insertions, 1 deletions
diff --git a/survey.py b/survey.py
index 69f6120..7dd32c9 100755
--- a/survey.py
+++ b/survey.py
@@ -128,7 +128,28 @@ def observe(word, pc, map):
     ValueError: label reference out of range (8 bit): 'label' (0x1234)
     """
     if not subv.is_reference(word):
-        return word
+        if len(word) != 2:
+            return word
+
+        ref = subv.parse_immediate(word[1])
+        if not ref or "split" not in ref:
+            return word
+
+        value = word[0]
+
+        sgn = -1 if value < 0 else 1
+        value *= sgn
+
+        if ref["split"] == "hi" and ref["size"] == 20:
+            value = value >> 12
+        elif ref["split"] == "lo" and ref["size"] == 12:
+            value = value & 0xFFF
+        else:
+            raise ValueError(
+                "unknown label split mode {mode}{size}{split}".format(**ref)
+            )
+
+        return (value, "imm{size}".format(**ref))
 
     ref = subv.parse_reference(word)