Make memory an object

state.go

@@ -15,13 +15,14 @@ type State struct {
 	instructionIndex int64
 
 	comparisonResult bool
-	globalMemory     [globalMemoryEntries]uint64
+	globalMemory     *memory
 	stack            []*stackFrame
 }
 
 func NewState(functions [][]*Instruction) (*State, error) {
 	return &State{
-		functions: functions,
+		functions:    functions,
+		globalMemory: newMemory(globalMemoryEntries),
 	}, nil
 }
 
@@ -97,11 +98,11 @@ func (state *State) readUnsigned(op *Operand) uint64 {
 		return state.stackFrame().functionMemory[op.Value]
 
 	case GlobalMemoryIndex:
-		if op.Value >= globalMemoryEntries {
-			state.setError(fmt.Errorf("Invalid global memory index: %016x", op.Value))
-			return 0
+		value, err := state.globalMemory.readUnsigned(op.Value)
+		if err != nil {
+			state.setError(err)
 		}
-		return state.globalMemory[op.Value]
+		return value
 
 	default:
 		state.setError(fmt.Errorf("Unknown operand type: 0x%02x", op.Type))
@@ -126,11 +127,10 @@ func (state *State) writeUnsigned(op *Operand, value uint64) {
 		state.stackFrame().functionMemory[op.Value] = value
 
 	case GlobalMemoryIndex:
-		if op.Value >= globalMemoryEntries {
-			state.setError(fmt.Errorf("Invalid global memory index: %016x", op.Value))
-			return
+		err := state.globalMemory.writeUnsigned(op.Value, value)
+		if err != nil {
+			state.setError(err)
 		}
-		state.globalMemory[op.Value] = value
 
 	default:
 		state.setError(fmt.Errorf("Unknown operand type: 0x%02x", op.Type))