feat: added bitwise coverage solidity example contract (#519)

contracts/yul/bitwise-coverage/Bitwise.sol

@@ -0,0 +1,65 @@
+// SPDX-License-Identifier: Apache-2.0
+pragma solidity ^0.8.20;
+
+contract Bitwise {
+    /// bitwise “not” of x (every bit of x is negated)
+    /// example x = 2 => not(x) = -3
+    /// explanation: x = 2 => binaryX = 0|0010 => ~binaryX = 1|1101
+    ///              1's complement (flip bit) 1sX = 1|0010
+    ///              2's complement (add 1) 2sX = 1|0010 + 1 = 1|0011 => -3    
+    function not(int256 x) external pure returns (int256 result) {
+        assembly {
+            result := not(x)
+        }
+    }
+
+    /// bitwise “and” of x and y
+    function and(int256 x, int256 y) external pure returns (int256 result) {
+        assembly {
+            result := and(x, y)
+        }
+    }
+
+    /// bitwise or” of x and y
+    function or(int256 x, int256 y) external pure returns (int256 result) {
+        assembly {
+            result := or(x, y)
+        }
+    }
+
+    /// bitwise “xor” of x and y
+    function xor(int256 x, int256 y) external pure returns (int256 result) {
+        assembly {
+            result := xor(x, y)
+        }
+    }
+
+    /// nth byte of x, where the most significant byte is the 0th byte
+    function extractbyteat(uint256 n, uint256 x) external pure returns (uint256 result) {
+        assembly {
+            result := byte(n , x)
+        }
+    }
+
+    /// logical shift left y by x bits
+    function shl(int256 x, int256 y) external pure returns (int256 result) {
+        assembly {
+            result := shl(x, y)
+        }
+    }
+
+    /// logical shift right y by x bits
+    function shr(uint256 x, uint256 y) external pure returns (uint256 result) {
+        assembly {
+            result := shr(x, y)
+        }
+    }
+
+    /// signed arithmetic shift right y by x bits
+    function sar(int256 x, int256 y) external pure returns (int256 result) {
+        assembly {
+            result := sar(x, y)
+        }
+    }
+}
+

test/yul/bitwise-coverage/Bitwise.js

@@ -0,0 +1,80 @@
+/*-
+ *
+ * Hedera Smart Contracts
+ *
+ * Copyright (C) 2023 Hedera Hashgraph, LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+const { expect } = require('chai')
+const { ethers } = require('hardhat')
+
+describe('@solidityequiv5 Bitwise Tests', () => {
+  let bitwiseContract
+  const X = 1
+  const Y = 12
+
+  before(async () => {
+    const bitwiseContractFactory = await ethers.getContractFactory('Bitwise')
+    bitwiseContract = await bitwiseContractFactory.deploy()
+  })
+
+  it('Should execute not(x)', async () => {
+    const result = await bitwiseContract.not(Y)
+    expect(result).to.eq(~Y)
+  })
+
+  it('Should execute and(x, y)', async () => {
+    const result = await bitwiseContract.and(X, Y)
+    expect(result).to.eq(X & Y)
+  })
+
+  it('Should execute or(x, y)', async () => {
+    const result = await bitwiseContract.or(X, Y)
+    expect(result).to.eq(X | Y)
+  })
+
+  it('Should execute xor(x, y)', async () => {
+    const result = await bitwiseContract.xor(X, Y)
+    expect(result).to.eq(X ^ Y)
+  })
+
+  it('Should execute extractbyteat(n, x)', async () => {
+    const DATA = 0x01020304
+    const N = 31 // 32nd byte - since `DATA` is supposed to be a 256-bit (32 bytes) unsigned integer, Solidity will convert the `DATA` to bytes32 by padding 0s in front of the actual data
+    const EXPECTED_RESULT = 4 // last byte
+
+    const result = await bitwiseContract.extractbyteat(N, DATA)
+
+    expect(result).to.eq(EXPECTED_RESULT)
+  })
+
+  it('Should execute shl(x, y)', async () => {
+    const result = await bitwiseContract.shl(X, Y)
+    expect(result).to.eq(Y << X)
+  })
+
+  it('Should execute shr(x, y)', async () => {
+    const result = await bitwiseContract.shr(X, Y)
+    expect(result).to.eq(Y >> X)
+  })
+
+  it('Should execute sar(x, y)', async () => {
+    const SX = -3
+    const SY = -9
+    const result = await bitwiseContract.sar(SX, SY)
+    expect(result).to.eq(SY >> SX)
+  })
+})