From 1f16cbc8d1bae19d628d423afe865c33e3957aaa Mon Sep 17 00:00:00 2001
From: Roman Behma <13855864+begmaroman@users.noreply.github.com>
Date: Wed, 24 May 2023 18:12:00 +0100
Subject: [PATCH] Introduce BASEFEE opcode (#1469)

---
 .../test-contracts/TestWriteBlockMetadata.sol          |  2 +-
 state/runtime/evm/dispatch_table.go                    |  1 +
 state/runtime/evm/instructions.go                      | 10 ++++++++++
 state/runtime/evm/opcodes.go                           |  4 ++++
 4 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/consensus/polybft/contractsapi/test-contracts/TestWriteBlockMetadata.sol b/consensus/polybft/contractsapi/test-contracts/TestWriteBlockMetadata.sol
index 90fe2a2ee3..c24384b34b 100644
--- a/consensus/polybft/contractsapi/test-contracts/TestWriteBlockMetadata.sol
+++ b/consensus/polybft/contractsapi/test-contracts/TestWriteBlockMetadata.sol
@@ -13,7 +13,7 @@ contract TestWriteBlockMetadata {
         data.push(block.gaslimit);
         data.push(block.chainid);
         coinbase = block.coinbase;
-        // data.push(block.basefee);
+        data.push(block.basefee);
         // hash = blockhash(block.number);
     }
 }
\ No newline at end of file
diff --git a/state/runtime/evm/dispatch_table.go b/state/runtime/evm/dispatch_table.go
index 7214a18dcd..e8afeae0f5 100644
--- a/state/runtime/evm/dispatch_table.go
+++ b/state/runtime/evm/dispatch_table.go
@@ -123,6 +123,7 @@ func init() {
 	register(NUMBER, handler{opNumber, 0, 2})
 	register(DIFFICULTY, handler{opDifficulty, 0, 2})
 	register(GASLIMIT, handler{opGasLimit, 0, 2})
+	register(BASEFEE, handler{opBaseFee, 0, 2})
 
 	register(SELFDESTRUCT, handler{opSelfDestruct, 1, 0})
 
diff --git a/state/runtime/evm/instructions.go b/state/runtime/evm/instructions.go
index 9ef721115e..5c1bccf489 100644
--- a/state/runtime/evm/instructions.go
+++ b/state/runtime/evm/instructions.go
@@ -907,6 +907,16 @@ func opGasLimit(c *state) {
 	c.push1().SetInt64(c.host.GetTxContext().GasLimit)
 }
 
+func opBaseFee(c *state) {
+	if !c.config.London {
+		c.exit(errOpCodeNotFound)
+
+		return
+	}
+
+	c.push(c.host.GetTxContext().BaseFee)
+}
+
 func opSelfDestruct(c *state) {
 	if c.inStaticCall() {
 		c.exit(errWriteProtection)
diff --git a/state/runtime/evm/opcodes.go b/state/runtime/evm/opcodes.go
index 85bd02d1c5..409180d4dc 100644
--- a/state/runtime/evm/opcodes.go
+++ b/state/runtime/evm/opcodes.go
@@ -161,6 +161,9 @@ const (
 	// SELFBALANCE returns the balance of the current account
 	SELFBALANCE = 0x47
 
+	// BASEFEE returns the current base fee value
+	BASEFEE = 0x48
+
 	// POP pops a (u)int256 off the stack and discards it
 	POP = 0x50
 
@@ -308,6 +311,7 @@ var opCodeToString = map[OpCode]string{
 	NUMBER:         "NUMBER",
 	DIFFICULTY:     "DIFFICULTY",
 	GASLIMIT:       "GASLIMIT",
+	BASEFEE:        "BASEFEE",
 	POP:            "POP",
 	MLOAD:          "MLOAD",
 	MSTORE:         "MSTORE",