primitive-types: add U128 full_mul

primitive-types/CHANGELOG.md

@@ -5,6 +5,9 @@ The format is based on [Keep a Changelog].
 [Keep a Changelog]: http://keepachangelog.com/en/1.0.0/
 
 ## [Unreleased]
+- Added `U128::full_mul` method. [#546](https://github.com/paritytech/parity-common/pull/546)
+### Breaking
+- Updated `scale-info` to 0.6. [#519](https://github.com/paritytech/parity-common/pull/519)
 
 ## [0.9.0] - 2021-01-27
 ### Breaking

primitive-types/src/lib.rs

@@ -125,6 +125,15 @@ mod rlp {
 
 impl_fixed_hash_conversions!(H256, H160);
 
+impl U128 {
+	/// Multiplies two 128-bit integers to produce full 256-bit integer
+	/// No overflow possible
+	#[inline(always)]
+	pub fn full_mul(self, other: U128) -> U256 {
+		U256(uint_full_mul_reg!(U128, 2, self, other))
+	}
+}
+
 impl U256 {
 	/// Multiplies two 256-bit integers to produce full 512-bit integer
 	/// No overflow possible