From 608d3355d50500ff6b04b6d995fc49e966cceced Mon Sep 17 00:00:00 2001
From: Mason Fischer <mason@kissr.co>
Date: Wed, 22 Jan 2020 14:55:39 -0500
Subject: [PATCH] Add mstoreBytes

---
 core/vm/instructions.go | 10 +++++-----
 tests/ovm_test.go       | 33 +++++++++++++++++++--------------
 2 files changed, 24 insertions(+), 19 deletions(-)

diff --git a/core/vm/instructions.go b/core/vm/instructions.go
index 5935a5cd5d..61c719f617 100644
--- a/core/vm/instructions.go
+++ b/core/vm/instructions.go
@@ -32,9 +32,9 @@ import (
 var (
 	bigZero                  = new(big.Int)
 	tt255                    = math.BigPow(2, 255)
-	ovmSLOADMethodId         = hashSha3([]byte("ovmSLOAD()"))[0:4]
-	ovmSSTOREMethodId        = hashSha3([]byte("ovmSStore()"))[0:4]
-	ovmContractAddress       = []byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1}
+	OvmSLOADMethodId         = hashSha3([]byte("ovmSLOAD()"))[0:4]
+	OvmSSTOREMethodId        = hashSha3([]byte("ovmSStore()"))[0:4]
+	OvmContractAddress       = []byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1}
 	errWriteProtection       = errors.New("evm: write protection")
 	errReturnDataOutOfBounds = errors.New("evm: return data out of bounds")
 	errExecutionReverted     = errors.New("evm: execution reverted")
@@ -778,10 +778,10 @@ func opCall(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory
 	args := memory.GetPtr(inOffset.Int64(), inSize.Int64())
 	fmt.Printf("args 0%x\n", args)
 
-	if bytes.Equal(toAddr.Bytes(), ovmContractAddress) && bytes.Equal(args, ovmSLOADMethodId) {
+	if bytes.Equal(toAddr.Bytes(), OvmContractAddress) && bytes.Equal(args, OvmSLOADMethodId) {
 		fmt.Println("SLOAD")
 	}
-	if bytes.Equal(toAddr.Bytes(), ovmContractAddress) && bytes.Equal(args, ovmSSTOREMethodId) {
+	if bytes.Equal(toAddr.Bytes(), OvmContractAddress) && bytes.Equal(args, OvmSSTOREMethodId) {
 		fmt.Println("SSTORE")
 	}
 	if value.Sign() != 0 {
diff --git a/tests/ovm_test.go b/tests/ovm_test.go
index e1e90e7015..9b7d9e8576 100644
--- a/tests/ovm_test.go
+++ b/tests/ovm_test.go
@@ -1,6 +1,7 @@
 package tests
 
 import (
+	"fmt"
 	"testing"
 
 	"github.com/ethereum/go-ethereum/common"
@@ -10,23 +11,25 @@ import (
 	"github.com/ethereum/go-ethereum/core/vm/runtime"
 )
 
+func mstoreBytes(bytes []byte) []byte {
+	output := make([]byte, len(bytes)*5)
+	for i, b := range bytes {
+		output[i*5] = byte(vm.PUSH1)
+		output[i*5+1] = b
+		output[i*5+2] = byte(vm.PUSH1)
+		output[i*5+3] = byte(i)
+		output[i*5+4] = byte(vm.MSTORE8)
+	}
+	return output
+}
+
 func TestOvm(t *testing.T) {
 	db := state.NewDatabase(rawdb.NewMemoryDatabase())
 	state, _ := state.New(common.Hash{}, db)
 	address := common.HexToAddress("0x0a")
-	code := []byte{
-		byte(vm.PUSH1), 0x20,
-		byte(vm.PUSH1), 0,
-		byte(vm.MSTORE8),
-		byte(vm.PUSH1), 0x96,
-		byte(vm.PUSH1), 1,
-		byte(vm.MSTORE8),
-		byte(vm.PUSH1), 0x62,
-		byte(vm.PUSH1), 2,
-		byte(vm.MSTORE8),
-		byte(vm.PUSH1), 0x08,
-		byte(vm.PUSH1), 3,
-		byte(vm.MSTORE8),
+	fmt.Printf("%x\n", mstoreBytes(vm.OvmSLOADMethodId))
+	code := mstoreBytes(vm.OvmSLOADMethodId)
+	code = append(code, []byte{
 		byte(vm.PUSH1), 0,
 		byte(vm.PUSH1), 0,
 		byte(vm.PUSH1), 0,
@@ -38,7 +41,9 @@ func TestOvm(t *testing.T) {
 		byte(vm.PUSH20), 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1,
 		byte(vm.GAS),
 		byte(vm.CALL),
-	}
+	}...)
+
+	fmt.Printf("%x", code)
 	state.SetCode(address, code)
 
 	_, _, err := runtime.Call(address, nil, &runtime.Config{State: state, Debug: true})