Eip 1344 (ChainID opcode) (#19921)

* core/vm: implement EIP 1344 (ChainID opcode)

* core/vm: formatting

core/vm/eips.go

@@ -18,7 +18,7 @@ package vm
 
 import (
 	"fmt"
-	
+
 	"github.com/ethereum/go-ethereum/params"
 )
 
@@ -29,6 +29,8 @@ func EnableEIP(eipNum int, jt *JumpTable) error {
 	switch eipNum {
 	case 1884:
 		enable1884(jt)
+	case 1344:
+		enable1344(jt)
 	default:
 		return fmt.Errorf("undefined eip %d", eipNum)
 	}
@@ -61,3 +63,23 @@ func opSelfBalance(pc *uint64, interpreter *EVMInterpreter, contract *Contract,
 	stack.push(balance)
 	return nil, nil
 }
+
+// enable1344 applies EIP-1344 (ChainID Opcode)
+// - Adds an opcode that returns the current chain’s EIP-155 unique identifier
+func enable1344(jt *JumpTable) {
+	// New opcode
+	jt[CHAINID] = operation{
+		execute:     opChainID,
+		constantGas: GasQuickStep,
+		minStack:    minStack(0, 1),
+		maxStack:    maxStack(0, 1),
+		valid:       true,
+	}
+}
+
+// opChainID implements CHAINID opcode
+func opChainID(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
+	chainId := interpreter.intPool.get().Set(interpreter.evm.chainConfig.ChainID)
+	stack.push(chainId)
+	return nil, nil
+}