From 30b157a126a27bda91c915c9541c3b50141ec60a Mon Sep 17 00:00:00 2001
From: Mason Fischer <mason@kissr.co>
Date: Wed, 22 Jan 2020 16:30:47 -0500
Subject: [PATCH] Complete an ovmSSTORE and ovmSLOAD roundtrip test

---
 core/vm/instructions.go | 50 ++++++++++++++++++-----------------------
 tests/ovm_test.go       | 27 ++++++++++++++++++++--
 2 files changed, 47 insertions(+), 30 deletions(-)

diff --git a/core/vm/instructions.go b/core/vm/instructions.go
index 243ff9a484..956ecbd89c 100644
--- a/core/vm/instructions.go
+++ b/core/vm/instructions.go
@@ -19,7 +19,6 @@ package vm
 import (
 	"bytes"
 	"errors"
-	"fmt"
 	"math/big"
 
 	"github.com/ethereum/go-ethereum/common"
@@ -768,43 +767,38 @@ func opCall(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory
 	toAddr := common.BigToAddress(addr)
 	value = math.U256(value)
 
-	fmt.Printf("value %s\n", value)
-	fmt.Printf("inOffset %s\n", inOffset)
-	fmt.Printf("inSize %s\n", inSize)
-	fmt.Printf("retOffset %s\n", retOffset)
-	fmt.Printf("retSize %s\n", retSize)
-	fmt.Printf("address 0x%020x\n", addr)
 	// Get the arguments from the memory.
 	args := memory.GetPtr(inOffset.Int64(), inSize.Int64())
-	fmt.Printf("args 0%x\n", args)
 
 	if bytes.Equal(toAddr.Bytes(), OvmContractAddress) && bytes.Equal(args[0:4], OvmSLOADMethodId) {
-		fmt.Println("SLOAD")
-	}
-	if bytes.Equal(toAddr.Bytes(), OvmContractAddress) && bytes.Equal(args[0:4], OvmSSTOREMethodId) {
-		fmt.Printf("SSTORE %v %v\n", args[4:35], args[36:68])
+		loc := common.BytesToHash(args[4:35])
+		val := interpreter.evm.StateDB.GetState(contract.Address(), loc)
+		stack.push(val.Big())
+		return val.Bytes(), nil
+	} else if bytes.Equal(toAddr.Bytes(), OvmContractAddress) && bytes.Equal(args[0:4], OvmSSTOREMethodId) {
 		loc := common.BytesToHash(args[4:35])
 		val := common.BytesToHash(args[36:68])
 		interpreter.evm.StateDB.SetState(contract.Address(), loc, val)
-
 		interpreter.intPool.put(val.Big())
-	}
-	if value.Sign() != 0 {
-		gas += params.CallStipend
-	}
-	ret, returnGas, err := interpreter.evm.Call(contract, toAddr, args, gas, value)
-	if err != nil {
-		stack.push(interpreter.intPool.getZero())
+		return nil, nil
 	} else {
-		stack.push(interpreter.intPool.get().SetUint64(1))
-	}
-	if err == nil || err == errExecutionReverted {
-		memory.Set(retOffset.Uint64(), retSize.Uint64(), ret)
-	}
-	contract.Gas += returnGas
+		if value.Sign() != 0 {
+			gas += params.CallStipend
+		}
+		ret, returnGas, err := interpreter.evm.Call(contract, toAddr, args, gas, value)
+		if err != nil {
+			stack.push(interpreter.intPool.getZero())
+		} else {
+			stack.push(interpreter.intPool.get().SetUint64(1))
+		}
+		if err == nil || err == errExecutionReverted {
+			memory.Set(retOffset.Uint64(), retSize.Uint64(), ret)
+		}
+		contract.Gas += returnGas
 
-	interpreter.intPool.put(addr, value, inOffset, inSize, retOffset, retSize)
-	return ret, nil
+		interpreter.intPool.put(addr, value, inOffset, inSize, retOffset, retSize)
+		return ret, nil
+	}
 }
 
 func opCallCode(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
diff --git a/tests/ovm_test.go b/tests/ovm_test.go
index 1d8ec9ebbe..df3bdfde37 100644
--- a/tests/ovm_test.go
+++ b/tests/ovm_test.go
@@ -1,6 +1,7 @@
 package tests
 
 import (
+	"bytes"
 	"testing"
 
 	"github.com/ethereum/go-ethereum/common"
@@ -11,7 +12,7 @@ import (
 )
 
 var KEY = common.FromHex("0102030000000000000000000000000000000000000000000000000000000000")
-var VALUE = common.FromHex("0405060000000000000000000000000000000000000000000000000000000001")
+var VALUE = common.FromHex("0405060000000000000000000000000000000000000000000000000000000000")
 
 func mstoreBytes(bytes []byte, offset int) []byte {
 	output := make([]byte, len(bytes)*5)
@@ -60,11 +61,33 @@ func TestOvm(t *testing.T) {
 			68,
 			0,
 			0)...)
+	code = append(code, mstoreBytes(vm.OvmSLOADMethodId, 0)...)
+	code = append(code, mstoreBytes(KEY, 4)...)
+	code = append(code,
+		call(
+			vm.OvmContractAddress,
+			0,
+			0,
+			36,
+			0,
+			0)...)
+	code = append(code, []byte{
+		byte(vm.PUSH1), 0,
+		byte(vm.MSTORE),
+		byte(vm.PUSH1), 32,
+		byte(vm.PUSH1), 0,
+		byte(vm.RETURN),
+	}...)
 
 	state.SetCode(address, code)
 
-	_, _, err := runtime.Call(address, nil, &runtime.Config{State: state, Debug: true})
+	returnValue, _, err := runtime.Call(address, nil, &runtime.Config{State: state, Debug: true})
 	if err != nil {
 		t.Fatal("didn't expect error", err)
 	}
+
+	if !bytes.Equal(returnValue, VALUE) {
+		t.Errorf("Expected %020x; got %020x", returnValue, VALUE)
+	}
+
 }