diff --git a/yarn-project/noir-protocol-circuits/src/crates/types/src/utils/uint256.nr b/yarn-project/noir-protocol-circuits/src/crates/types/src/utils/uint256.nr index 82d581796bf..7731218c9eb 100644 --- a/yarn-project/noir-protocol-circuits/src/crates/types/src/utils/uint256.nr +++ b/yarn-project/noir-protocol-circuits/src/crates/types/src/utils/uint256.nr @@ -14,41 +14,42 @@ struct U256 { impl U256 { pub fn from_bytes32(bytes : [u8;32]) -> U256 { + // We use addition rather than a bitwise OR as the bitshifts ensure that none of the bytes overlap each other. let high_0 = ((bytes[0] as u64) << 56) - | ((bytes[1] as u64) << 48) - | ((bytes[2] as u64) << 40) - | ((bytes[3] as u64) << 32) - | ((bytes[4] as u64) << 24) - | ((bytes[5] as u64) << 16) - | ((bytes[6] as u64) << 8) - | (bytes[7] as u64); + + ((bytes[1] as u64) << 48) + + ((bytes[2] as u64) << 40) + + ((bytes[3] as u64) << 32) + + ((bytes[4] as u64) << 24) + + ((bytes[5] as u64) << 16) + + ((bytes[6] as u64) << 8) + + (bytes[7] as u64); let high_1 = ((bytes[8] as u64) << 56) - | ((bytes[9] as u64) << 48) - | ((bytes[10] as u64) << 40) - | ((bytes[11] as u64) << 32) - | ((bytes[12] as u64) << 24) - | ((bytes[13] as u64) << 16) - | ((bytes[14] as u64) << 8) - | (bytes[15] as u64); + + ((bytes[9] as u64) << 48) + + ((bytes[10] as u64) << 40) + + ((bytes[11] as u64) << 32) + + ((bytes[12] as u64) << 24) + + ((bytes[13] as u64) << 16) + + ((bytes[14] as u64) << 8) + + (bytes[15] as u64); let low_0 = ((bytes[16] as u64) << 56) - | ((bytes[17] as u64) << 48) - | ((bytes[18] as u64) << 40) - | ((bytes[19] as u64) << 32) - | ((bytes[20] as u64) << 24) - | ((bytes[21] as u64) << 16) - | ((bytes[22] as u64) << 8) - | (bytes[23] as u64); + + ((bytes[17] as u64) << 48) + + ((bytes[18] as u64) << 40) + + ((bytes[19] as u64) << 32) + + ((bytes[20] as u64) << 24) + + ((bytes[21] as u64) << 16) + + ((bytes[22] as u64) << 8) + + (bytes[23] as u64); let low_1 = ((bytes[24] as u64) << 56) - | ((bytes[25] as u64) << 48) - | ((bytes[26] as u64) << 40) - | ((bytes[27] as u64) << 32) - | ((bytes[28] as u64) << 24) - | ((bytes[29] as u64) << 16) - | ((bytes[30] as u64) << 8) - | (bytes[31] as u64); + + ((bytes[25] as u64) << 48) + + ((bytes[26] as u64) << 40) + + ((bytes[27] as u64) << 32) + + ((bytes[28] as u64) << 24) + + ((bytes[29] as u64) << 16) + + ((bytes[30] as u64) << 8) + + (bytes[31] as u64); U256{inner : [high_0, high_1, low_0, low_1]} }