Add cond CC flag simplification

3 files changed, 46 insertions, 0 deletions

diff --git a/miasm/expression/simplifications.py b/miasm/expression/simplifications.py
index 3f54b158..c65b2b7b 100644
--- a/miasm/expression/simplifications.py
+++ b/miasm/expression/simplifications.py
@@ -86,6 +86,7 @@ class ExpressionSimplifier(ExprVisitorCallbackBottomToTop):
             simplifications_common.simp_cond_logic_ext,
             simplifications_common.simp_cond_sign_bit,
             simplifications_common.simp_cond_eq_1_0,
+            simplifications_common.simp_cond_cc_flag,
         ],
         m2_expr.ExprMem: [simplifications_common.simp_mem],
 
diff --git a/miasm/expression/simplifications_common.py b/miasm/expression/simplifications_common.py
index 932db49a..dc9fadea 100644
--- a/miasm/expression/simplifications_common.py
+++ b/miasm/expression/simplifications_common.py
@@ -919,6 +919,26 @@ def simp_sub_cf_zero(_, expr):
         return expr
     return ExprCond(expr.args[1], ExprInt(1, 1), ExprInt(0, 1))
 
+def simp_cond_cc_flag(expr_simp, expr):
+    """
+    ExprCond(CC_><(bit), X, Y) => ExprCond(bit, X, Y)
+    ExprCond(CC_U>=(bit), X, Y) => ExprCond(bit, Y, X)
+    """
+    if not expr.is_cond():
+        return expr
+    if not expr.cond.is_op():
+        return expr
+    expr_op = expr.cond
+    if expr_op.op not in ["CC_U<", "CC_U>="]:
+        return expr
+    arg = expr_op.args[0]
+    if arg.size != 1:
+        return expr
+    if expr_op.op == "CC_U<":
+        return ExprCond(arg, expr.src1, expr.src2)
+    if expr_op.op == "CC_U>=":
+        return ExprCond(arg, expr.src2, expr.src1)
+    return expr
 
 def simp_cmp_int(expr_simp, expr):
     """
diff --git a/test/expression/simplifications.py b/test/expression/simplifications.py
index 1f243425..c75dc0d3 100644
--- a/test/expression/simplifications.py
+++ b/test/expression/simplifications.py
@@ -784,6 +784,31 @@ to_test = [
         ExprOp(TOK_EQUAL, a, i0)
     ),
 
+
+    (
+        ExprCond(
+            ExprOp("CC_U<", a[0:1]),
+            b, c
+        ),
+        ExprCond(
+            a[0:1],
+            b, c
+        ),
+    ),
+
+    (
+        ExprCond(
+            ExprOp("CC_U>=", a[0:1]),
+            b, c
+        ),
+        ExprCond(
+            a[0:1],
+            c, b
+        ),
+    ),
+
+
+
 ]
 
 for e_input, e_check in to_test: