Merge pull request #6941 from gabor-mezei-arm/6375_quasi-reduction_function

Add function to fix quasi-reduction

scripts/mbedtls_dev/bignum_mod_raw.py

@@ -51,6 +51,37 @@ class BignumModRawSub(bignum_common.ModOperationCommon,
         result = (self.int_a - self.int_b) % self.int_n
         return [self.format_result(result)]
 
+class BignumModRawFixQuasiReduction(bignum_common.ModOperationCommon,
+                                    BignumModRawTarget):
+    """Test cases for ecp quasi_reduction()."""
+    symbol = "-"
+    test_function = "mpi_mod_raw_fix_quasi_reduction"
+    test_name = "fix_quasi_reduction"
+    input_style = "fixed"
+    arity = 1
+
+    # Extend the default values with n < x < 2n
+    input_values = bignum_common.ModOperationCommon.input_values + [
+        "73",
+
+        # First number generated by random.getrandbits(1024) - seed(3,2)
+        "ea7b5bf55eb561a4216363698b529b4a97b750923ceb3ffd",
+
+        # First number generated by random.getrandbits(1024) - seed(1,2)
+        ("cd447e35b8b6d8fe442e3d437204e52db2221a58008a05a6c4647159c324c985"
+         "9b810e766ec9d28663ca828dd5f4b3b2e4b06ce60741c7a87ce42c8218072e8c"
+         "35bf992dc9e9c616612e7696a6cecc1b78e510617311d8a3c2ce6f447ed4d57b"
+         "1e2feb89414c343c1027c4d1c386bbc4cd613e30d8f16adf91b7584a2265b1f5")
+    ] # type: List[str]
+
+    def result(self) -> List[str]:
+        result = self.int_a % self.int_n
+        return [self.format_result(result)]
+
+    @property
+    def is_valid(self) -> bool:
+        return bool(self.int_a < 2 * self.int_n)
+
 class BignumModRawMul(bignum_common.ModOperationCommon,
                       BignumModRawTarget):
     """Test cases for bignum mpi_mod_raw_mul()."""