[Unitary Hack] Qint integer division #27

qlasskit/ast2logic/t_expression.py

@@ -290,6 +290,8 @@ def unfold(v_exps, op):
             return tright[0].bitwise_and(tleft, tright)  # type: ignore
         elif isinstance(expr.op, ast.BitOr) and hasattr(tleft[0], "bitwise_or"):
             return tleft[0].bitwise_or(tleft, tright)
+        elif isinstance(expr.op, ast.FloorDiv) and hasattr(tleft[0], "floor_div"):
+            return tleft[0].floor_div(tleft, tright)
         elif (
             isinstance(expr.op, ast.LShift)
             and hasattr(tleft[0], "shift_left")

qlasskit/types/qint.py

@@ -317,6 +317,33 @@ def bitwise_and(cls, tleft: TExp, tright: TExp) -> TExp:
     def bitwise_or(cls, tleft: TExp, tright: TExp) -> TExp:
         return cls.bitwise_generic(Or, tleft, tright)
 
+    @classmethod
+    def floor_div(cls, tleft: TExp, tright: TExp) -> TExp:
+        """Perform floor division on two Qint"""
+        if not issubclass(tleft[0], Qtype):
+            raise TypeErrorException(tleft[0], Qtype)
+        if not issubclass(tright[0], Qtype):
+            raise TypeErrorException(tright[0], Qtype)
+
+        tright_e = cast(Qtype, tright)
+        tleft_e = cast(Qtype, tleft)
+
+        if len(tleft_e[1]) != len(tright_e[1]):
+            raise ValueError("Operands must be of the same bit length")
+
+        n = len(tleft_e[1])
+        Q = 0
+        R = 0
+
+        for i in range(n):
+            R <<= 1
+            R |= tleft_e[1][i]
+            if R >= tright_e[1]:
+                R ^= tright_e[1]
+                Q |= (1 << (n - 1 - i))
+
+        return (cls, Q)
+
 
 class Qint2(QintImp):
     BIT_SIZE = 2

qlasskit/types/qtype.py

@@ -227,3 +227,7 @@ def bitwise_and(tleft: TExp, tright: TExp) -> TExp:
     @staticmethod
     def bitwise_or(tleft: TExp, tright: TExp) -> TExp:
         raise Exception("abstract bitwise_or")
+
+    @staticmethod
+    def floor_div(tleft: TExp, tright: TExp) -> TExp:
+        raise Exception("abstract floor_div")

test/qlassf/test_int.py

@@ -59,6 +59,13 @@ def test_qint2_to_bin(self):
         self.assertEqual(c, "10")
         self.assertEqual(c, Qint2(1).export("binary"))
 
+    def test_floor_div(self):
+        self.assertEqual(Qint2.floor_div(Qint2(10), Qint2(3)), Qint2(3))
+        self.assertEqual(Qint2.floor_div(Qint2(20), Qint2(4)), Qint2(5))
+        self.assertEqual(Qint2.floor_div(Qint2(5), Qint2(2)), Qint2(2))
+        with self.assertRaises(ZeroDivisionError):
+            Qint2.floor_div(Qint2(10), Qint2(0))
+
 
 @parameterized_class(
     ("ttype_str", "ttype_size", "compiler"),