From 4ed9a49e9da6e39b8672ec8d235829bb21e71224 Mon Sep 17 00:00:00 2001
From: Sina Mahmoodi <itz.s1na@gmail.com>
Date: Mon, 18 Mar 2024 17:04:29 +0100
Subject: [PATCH] core/vm: PAY opcode EIP-5920

---
 core/vm/eips.go        | 26 ++++++++++++++++++++++++++
 core/vm/gas_table.go   | 18 ++++++++++++++++++
 core/vm/interpreter.go |  2 +-
 core/vm/opcodes.go     |  3 +++
 4 files changed, 48 insertions(+), 1 deletion(-)

diff --git a/core/vm/eips.go b/core/vm/eips.go
index 9f06b2818f..19bd5b79ee 100644
--- a/core/vm/eips.go
+++ b/core/vm/eips.go
@@ -37,6 +37,7 @@ var activators = map[int]func(*JumpTable){
 	1884: enable1884,
 	1344: enable1344,
 	1153: enable1153,
+	5920: enable5920,
 }
 
 // EnableEIP enables the given EIP on the config.
@@ -55,6 +56,7 @@ func ValidEip(eipNum int) bool {
 	_, ok := activators[eipNum]
 	return ok
 }
+
 func ActivateableEips() []string {
 	var nums []string
 	for k := range activators {
@@ -319,3 +321,27 @@ func enable6780(jt *JumpTable) {
 		maxStack:    maxStack(1, 0),
 	}
 }
+
+func enable5920(jt *JumpTable) {
+	jt[PAY] = &operation{
+		execute:     opPay,
+		constantGas: params.WarmStorageReadCostEIP2929,
+		dynamicGas:  gasPay,
+		minStack:    minStack(2, 0),
+		maxStack:    maxStack(2, 0),
+	}
+}
+
+func opPay(pc *uint64, interpreter *EVMInterpreter, scope *ScopeContext) ([]byte, error) {
+	if interpreter.readOnly {
+		return nil, ErrWriteProtection
+	}
+	var (
+		addr   = scope.Stack.pop()
+		amount = scope.Stack.pop()
+	)
+	if interpreter.evm.Context.CanTransfer(interpreter.evm.StateDB, scope.Contract.Address(), &amount) {
+		interpreter.evm.Context.Transfer(interpreter.evm.StateDB, scope.Contract.Address(), addr.Bytes20(), &amount)
+	}
+	return nil, nil
+}
diff --git a/core/vm/gas_table.go b/core/vm/gas_table.go
index 4b141d8f9a..fe253beec8 100644
--- a/core/vm/gas_table.go
+++ b/core/vm/gas_table.go
@@ -477,3 +477,21 @@ func gasSelfdestruct(evm *EVM, contract *Contract, stack *Stack, mem *Memory, me
 	}
 	return gas, nil
 }
+
+func gasPay(evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) {
+	var (
+		addr           = stack.peek().Bytes20()
+		transfersValue = !stack.Back(1).IsZero()
+	)
+	gas, err := gasEip2929AccountCheck(evm, contract, stack, mem, memorySize)
+	if err != nil {
+		return 0, err
+	}
+	if transfersValue {
+		gas += params.CallValueTransferGas
+		if evm.StateDB.Empty(addr) {
+			gas += params.CallNewAccountGas
+		}
+	}
+	return gas, nil
+}
diff --git a/core/vm/interpreter.go b/core/vm/interpreter.go
index 1968289f4e..4989f2fde6 100644
--- a/core/vm/interpreter.go
+++ b/core/vm/interpreter.go
@@ -189,7 +189,7 @@ func (in *EVMInterpreter) Run(contract *Contract, input []byte, readOnly bool) (
 			return nil, ErrOutOfGas
 		}
 		if operation.dynamicGas != nil {
-			// All ops with a dynamic memory usage also has a dynamic gas cost.
+			// All ops with a dynamic memory usage also have a dynamic gas cost.
 			var memorySize uint64
 			// calculate the new memory size and expand the memory to fit
 			// the operation
diff --git a/core/vm/opcodes.go b/core/vm/opcodes.go
index 2b9231fe1a..7c1f54705f 100644
--- a/core/vm/opcodes.go
+++ b/core/vm/opcodes.go
@@ -218,6 +218,7 @@ const (
 	DELEGATECALL OpCode = 0xf4
 	CREATE2      OpCode = 0xf5
 
+	PAY          OpCode = 0xf9
 	STATICCALL   OpCode = 0xfa
 	REVERT       OpCode = 0xfd
 	INVALID      OpCode = 0xfe
@@ -391,6 +392,7 @@ var opCodeToString = [256]string{
 	CALLCODE:     "CALLCODE",
 	DELEGATECALL: "DELEGATECALL",
 	CREATE2:      "CREATE2",
+	PAY:          "PAY",
 	STATICCALL:   "STATICCALL",
 	REVERT:       "REVERT",
 	INVALID:      "INVALID",
@@ -554,6 +556,7 @@ var stringToOp = map[string]OpCode{
 	"REVERT":         REVERT,
 	"INVALID":        INVALID,
 	"SELFDESTRUCT":   SELFDESTRUCT,
+	"PAY":            PAY,
 }
 
 // StringToOp finds the opcode whose name is stored in `str`.