From 3b95e0139062b594045b1541ca70910eb841e10d Mon Sep 17 00:00:00 2001
From: Dmitry Vagner <dmitry.vagner@gmail.com>
Date: Mon, 27 Mar 2023 21:10:23 -0700
Subject: [PATCH] bls method

---
 evm/src/cpu/kernel/tests/bls381.rs | 5 +----
 evm/src/extension_tower.rs         | 7 +++++++
 2 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/evm/src/cpu/kernel/tests/bls381.rs b/evm/src/cpu/kernel/tests/bls381.rs
index afd22a14..b8315b6f 100644
--- a/evm/src/cpu/kernel/tests/bls381.rs
+++ b/evm/src/cpu/kernel/tests/bls381.rs
@@ -1,5 +1,4 @@
 use anyhow::Result;
-use ethereum_types::U512;
 use rand::Rng;
 
 use crate::cpu::kernel::interpreter::{
@@ -19,9 +18,7 @@ fn run_and_return_bls(label: String, x: BLS381, y: BLS381) -> BLS381 {
     };
     let interpreter = run_interpreter_with_memory(setup).unwrap();
     let output = interpreter.stack();
-    BLS381 {
-        val: U512::from(output[1]) + (U512::from(output[0]) << 256),
-    }
+    BLS381::from_limbs(output[0], output[1])
 }
 
 #[test]
diff --git a/evm/src/extension_tower.rs b/evm/src/extension_tower.rs
index ddcfe254..72a1106c 100644
--- a/evm/src/extension_tower.rs
+++ b/evm/src/extension_tower.rs
@@ -144,6 +144,13 @@ impl BLS381 {
     pub fn hi(self) -> U256 {
         U256(self.val.0[4..].try_into().unwrap())
     }
+
+    pub fn from_limbs(hi: U256, lo: U256) -> BLS381 {
+        let mut val = [0u64; 8];
+        val[..4].copy_from_slice(&lo.0);
+        val[4..].copy_from_slice(&hi.0);
+        BLS381 { val: U512(val) }
+    }
 }
 
 impl Distribution<BLS381> for Standard {