readme and cleanup

1 files changed, 20 insertions, 8 deletions

diff --git a/vm/vm.go b/vm/vm.go
index 209ab71..7a6178f 100644
--- a/vm/vm.go
+++ b/vm/vm.go
@@ -11,6 +11,7 @@ type Evm struct {
 	memory Memory
 	pc uint64
 	stopped bool
+	returndata []byte
 }
 
 func NewEvm(_code []byte) *Evm {
@@ -19,25 +20,36 @@ func NewEvm(_code []byte) *Evm {
 		stopped: true,
 		stack : Stack{},
 		code: _code,
+		returndata: nil,
 	}
 }
 
-func (vm *Evm) Start() {
+func (vm *Evm) Run() []byte {
 	vm.stopped = false
+	fmt.Printf("code: ", vm.code)
 	for !(vm.stopped) {
-		op := vm.code.Fetch(&(vm.pc), 1)[0] 
-		fmt.Printf("pc: %d | opcode: %x -> string: %s\n", vm.pc, op, Instructions[op].name)
-		if op >= PUSH1 && op <= PUSH32 {
-			nb := op - PUSH1 + 1
-			fmt.Printf("pushing %d byte value to the stack!\n", vm.pc, nb)
-			b := vm.code.Fetch(&(vm.pc), uint64(nb))
+		s := vm.code.Fetch(&(vm.pc), 1)
+		op := Opcode(STOP)
+		if (s != nil) {
+			op = Opcode(s[0])
+		}
+
+		fmt.Printf("pc: %d | opcode: 0x%x -> string: %s\n", vm.pc, op, Instructions[op].name)
+		push := (&op).IsPush()
+		if (push != 0) {
+			b := vm.code.Fetch(&(vm.pc), uint64(push))
 		        x := uint256.NewInt(0)
 			x = x.SetBytes(b)
 			vm.stack.Push(x)
 		} else {
-			vm.Execute(op)
+			vm.Execute(byte(op))
 		}
+
+		if (op == RETURN) {
+			return vm.returndata
+		} 
 	}
+	return nil
 }
 
 func (vm *Evm) Execute(op byte) {