Conditional return instructions

vm/opcode.go

@@ -3,10 +3,8 @@ package vm
 type OpCodeType uint32
 
 const (
-	OpNoOp   OpCodeType = 0x00000000
-	OpNop               = OpNoOp
-	OpReturn            = 0x00000002
-	OpRet               = OpReturn
+	OpNoOp OpCodeType = 0x00000000
+	OpNop             = OpNoOp
 
 	OpMove = 0x00000100
 	OpMov  = OpMove
@@ -53,4 +51,11 @@ const (
 	OpCalT        = OpCallIfTrue
 	OpCallIfFalse = 0x00000502
 	OpCalF        = OpCallIfFalse
+
+	OpReturn        = 0x00000600
+	OpRet           = OpReturn
+	OpReturnIfTrue  = 0x00000601
+	OpRetT          = OpReturnIfTrue
+	OpReturnIfFalse = 0x00000602
+	OpRetF          = OpReturnIfFalse
 )

vm/ophandler.go

@@ -3,8 +3,7 @@ package vm
 type opHandler func(*State, *Instruction)
 
 var opHandlers = map[OpCodeType]opHandler{
-	OpNoOp:   (*State).handleNoOp,
-	OpReturn: (*State).handleReturn,
+	OpNoOp: (*State).handleNoOp,
 
 	OpMove: (*State).handleMove,
 
@@ -31,15 +30,15 @@ var opHandlers = map[OpCodeType]opHandler{
 	OpCall:        (*State).handleCall,
 	OpCallIfTrue:  (*State).handleCallIfTrue,
 	OpCallIfFalse: (*State).handleCallIfFalse,
+
+	OpReturn:        (*State).handleReturn,
+	OpReturnIfTrue:  (*State).handleReturnIfTrue,
+	OpReturnIfFalse: (*State).handleReturnIfFalse,
 }
 
 func (state *State) handleNoOp(instr *Instruction) {
 }
 
-func (state *State) handleReturn(instr *Instruction) {
-	state.ret()
-}
-
 func (state *State) handleMove(instr *Instruction) {
 	in := state.readUnsigned(&instr.Operand2)
 	state.writeUnsigned(&instr.Operand1, in)
@@ -162,3 +161,19 @@ func (state *State) handleCallIfFalse(instr *Instruction) {
 		state.handleCall(instr)
 	}
 }
+
+func (state *State) handleReturn(instr *Instruction) {
+	state.ret()
+}
+
+func (state *State) handleReturnIfTrue(instr *Instruction) {
+	if state.comparisonResult == true {
+		state.handleReturn(instr)
+	}
+}
+
+func (state *State) handleReturnIfFalse(instr *Instruction) {
+	if state.comparisonResult == false {
+		state.handleReturn(instr)
+	}
+}